A Solution to the Inherent List on Nimitz Class Aircraft Carriers
A Solution to the Inherent List on Nimitz Class Aircraft Carriers
A Solution to the Inherent List on Nimitz Class Aircraft Carriers
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A <str<strong>on</strong>g>Soluti<strong>on</strong></str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>Inherent</str<strong>on</strong>g> <str<strong>on</strong>g>List</str<strong>on</strong>g> <strong>on</strong> <strong>Nimitz</strong> <strong>Class</strong> <strong>Aircraft</strong> <strong>Carriers</strong><br />
by<br />
Dianna Wolf s<strong>on</strong><br />
B.S. Marine Engineering Systems, United States Merchant Marine Academy, 1996<br />
Submitted <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Departments of Ocean Engineering and Civil and Envir<strong>on</strong>mental Engineering<br />
in Partial Fulfillment of <str<strong>on</strong>g>the</str<strong>on</strong>g> Requirements for <str<strong>on</strong>g>the</str<strong>on</strong>g> Degrees of<br />
Naval Engineer<br />
and<br />
Master of Science in Civil and Envir<strong>on</strong>mental Engineering<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Massachusetts Institute of Technology<br />
June 2004<br />
© 2004 Dianna Wolfs<strong>on</strong><br />
All rights reserved<br />
The author hereby grants MIT and <str<strong>on</strong>g>the</str<strong>on</strong>g> U.S. Government permissi<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> reproduce and <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
distribute publicly paper and electr<strong>on</strong>ic copies of this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis document in whole or in part.<br />
Author<br />
Certified by<br />
Certified by<br />
Department of Ocean Engineering and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Department of Civil and Envir<strong>on</strong>mental Engineering<br />
May 07, 2004<br />
David V. Burke, Senior Lecturer<br />
Department of Ocean Engineering<br />
Thesis Supervisor<br />
Eduardo Kausel, Professor of Civil and Envir<strong>on</strong>mental Engineering<br />
Department of Civil and Envir<strong>on</strong>mental Engineering<br />
Thesis Reader<br />
Accepted by<br />
Heidi Nepf,<br />
ssociate Professor of Civil and Envir<strong>on</strong>mental Engineering<br />
Chairman, Departmental Committee <strong>on</strong> Graduate Studies<br />
Department of Civil and Envir<strong>on</strong>mental Engineering<br />
Accepted by<br />
DISTRIBUTION STATEMENT A<br />
Approved for Public Release<br />
Distributi<strong>on</strong> Unlimited<br />
Michael S. Triantafyllou, Professor of Ocean Engineering<br />
Chairman, Departmental Committee <strong>on</strong> Graduate Studies<br />
Department of Ocean Engineering<br />
BEST AVAILABLE COPY<br />
20040901 104
PAGE INTENTIONALLY LEFT BLANK
A <str<strong>on</strong>g>Soluti<strong>on</strong></str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>Inherent</str<strong>on</strong>g> <str<strong>on</strong>g>List</str<strong>on</strong>g> <strong>on</strong> <strong>Nimitz</strong> <strong>Class</strong> <strong>Aircraft</strong> <strong>Carriers</strong><br />
by<br />
Dianna Wolfs<strong>on</strong><br />
Abstract<br />
Submitted <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Departments of Ocean Engineering and<br />
Civil and Envir<strong>on</strong>mental Engineering<br />
<strong>on</strong> May 07, 2004, in partial fulfillment of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Requirements for <str<strong>on</strong>g>the</str<strong>on</strong>g> degrees of<br />
Naval Engineer<br />
and<br />
Master of Science in Civil and Envir<strong>on</strong>mental Engineering<br />
<strong>Nimitz</strong> class aircraft carriers possess an inherent list <str<strong>on</strong>g>to</str<strong>on</strong>g> starboard that <str<strong>on</strong>g>the</str<strong>on</strong>g>ir list c<strong>on</strong>trol<br />
systems (LCS) are typically unable <str<strong>on</strong>g>to</str<strong>on</strong>g> correct while under Combat Load C<strong>on</strong>diti<strong>on</strong>s. As a result,<br />
it has become necessary <str<strong>on</strong>g>to</str<strong>on</strong>g> use fresh water ballast in a number of inner bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m voids and damage<br />
c<strong>on</strong>trol voids <str<strong>on</strong>g>to</str<strong>on</strong>g> augment <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS. Maintaining liquid ballast in damage c<strong>on</strong>trol voids is<br />
unacceptable, as it reduces <str<strong>on</strong>g>the</str<strong>on</strong>g> design counter flooding capability of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship, and thus reduces<br />
ship survivability. In order <str<strong>on</strong>g>to</str<strong>on</strong>g> res<str<strong>on</strong>g>to</str<strong>on</strong>g>re <str<strong>on</strong>g>the</str<strong>on</strong>g> ships operati<strong>on</strong>al flexibility and achieve <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
necessary/desired list correcti<strong>on</strong>, this study determines <str<strong>on</strong>g>the</str<strong>on</strong>g> effect of adding solid ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> a<br />
series of voids/tanks identified <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2""^, 4*, and 8* decks.<br />
Based <strong>on</strong> ballast density, tank locati<strong>on</strong> and capacity, ease of ballast installati<strong>on</strong>, minor<br />
tank structural modificati<strong>on</strong>s, and a decisi<strong>on</strong> making cost analysis, solid ballast was determined<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> be <str<strong>on</strong>g>the</str<strong>on</strong>g> most advantageous for use in correcting <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class aircraft<br />
carriers. Fresh water ballast was also examined as a possible alternative, but not as extensively<br />
due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> large quantity of water required and its limited ability <str<strong>on</strong>g>to</str<strong>on</strong>g> achieve a list correcti<strong>on</strong>.<br />
<strong>Nimitz</strong> class aircraft carriers currently have an average list of L5 degrees and a KG of 47<br />
feet. Since <str<strong>on</strong>g>the</str<strong>on</strong>g>ir allowable KG cannot exceed 48.5 feet, <str<strong>on</strong>g>the</str<strong>on</strong>g> average service life allowance (SLA)<br />
for KG is approximately 1.5 feet. This study shows that by adding approximately 400 I<str<strong>on</strong>g>to</str<strong>on</strong>g>n of<br />
solid ballast, list can be corrected by 1.5 degrees with <strong>on</strong>ly a 0.1 percent increase in KG. Thus,<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> permanently fix <str<strong>on</strong>g>the</str<strong>on</strong>g> average <strong>Nimitz</strong> class aircraft carrier starboard list, <str<strong>on</strong>g>the</str<strong>on</strong>g>re would be a 0.05<br />
foot increase in KG, which in all cases is within <str<strong>on</strong>g>the</str<strong>on</strong>g> SLA. Additi<strong>on</strong>ally, this study shows that<br />
this L5 degree list correcti<strong>on</strong> can be accomplished at a low cost of approximately $1,200 per<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n. C<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> reducti<strong>on</strong> in operati<strong>on</strong>al c<strong>on</strong>straints and <str<strong>on</strong>g>the</str<strong>on</strong>g> benefits <str<strong>on</strong>g>to</str<strong>on</strong>g> ship survivability,<br />
this is truly an inexpensive propositi<strong>on</strong>.<br />
Thesis Supervisor: David V. Burke<br />
Title: Senior Lecturer<br />
Thesis Reader: Eduardo Kausel<br />
Title: Professor of Civil and Envir<strong>on</strong>mental Engineering
Acknowledgements<br />
I would like <str<strong>on</strong>g>to</str<strong>on</strong>g> thank CDR Kevin Terry who c<strong>on</strong>tacted MIT with a project proposal <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
find an advantageous and cost effective soluti<strong>on</strong> for fixing <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class<br />
aircraft carriers. Without his support, this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis would not have been possible.<br />
Throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> course of this project, many individuals from various organizati<strong>on</strong>s<br />
provided invaluable operati<strong>on</strong>al and technical assistance. I would like <str<strong>on</strong>g>to</str<strong>on</strong>g> take this opportunity <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
thank every<strong>on</strong>e for <str<strong>on</strong>g>the</str<strong>on</strong>g>ir c<strong>on</strong>tributi<strong>on</strong>s and advice. I would also like <str<strong>on</strong>g>to</str<strong>on</strong>g> thank my husband for his<br />
friendship, love, and encouragement over <str<strong>on</strong>g>the</str<strong>on</strong>g> past three years and always.<br />
NAVSEA<br />
CDR Kevin Terry<br />
CAPT (ret.) Chuck Bush<br />
CAPT T. Moore<br />
CAPT James Murdoch<br />
Dominick Cimino<br />
Roger M. Nutting<br />
Evelisse Marti r<br />
Wei d<strong>on</strong> Gimbel<br />
LCDR Brian Lawerence<br />
LCDR Rick Thiel<br />
Bath Ir<strong>on</strong> Works<br />
John Grostick<br />
Lew Pratt<br />
Allen Pac<br />
Ray Lacour<br />
LCDR Michael Taylor<br />
CVN Ships<br />
LCDR Chariie Strassle (DCA, CVN 69)<br />
CDR Robert Finely (Cheng, CVN 71)<br />
LCDR Peter Pasquale (DCA, CVN 71)<br />
LCDR John Rickards (DCA, CVN 72)<br />
LCDR Scott Noe (DCA, CVN 76)<br />
CDR Glenn Hofert (Cheng, CVN 76)<br />
Massachusetts Institute of Technology<br />
Dr. David V. Burke<br />
CDR (ret.) John Amy<br />
CDR Timothy McCoy<br />
NGC - Newport News Shipbuilding<br />
Jerry Dudley<br />
Hal McCaskill<br />
NSWC Carderock<br />
John M. Rosborough<br />
Carlos R. Corretjer<br />
Charlie Snelling<br />
Bruce Winterstein<br />
Todd Heidenreich<br />
PCCI. Inc.<br />
John A. 'T<strong>on</strong>y" Kupersmith<br />
Jessica R. Coles<br />
Herbert Engineering Corporati<strong>on</strong><br />
Colin Moore<br />
Norfolk Naval Shipvard<br />
Walt Del<strong>on</strong>g<br />
Larry Back<br />
Ballast Technologies. Inc.<br />
Mark Ensio<br />
N.S. NAPPI Associates<br />
Nat Nappi, Sr.<br />
#<br />
Please accept my apologies if I have left some<strong>on</strong>e off this list.
Table of C<strong>on</strong>tents<br />
Abstract 3<br />
Acknowledgements 4<br />
Table of C<strong>on</strong>tents 5<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Figures 6<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Tables 6<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Appendices 6<br />
1.0 Introducti<strong>on</strong> 7<br />
1.0 Introducti<strong>on</strong> 7<br />
1.1 Motivati<strong>on</strong> 7<br />
1.2 Background 7<br />
1.2.1 Past Research 10<br />
1.2.2 Stability 10<br />
1.2.3 Survivability 13<br />
1.2.4 Displacement Limits 14<br />
1.2.5 KG Limits 14<br />
1.3 Present Opti<strong>on</strong>s 15<br />
1.3.1 C<strong>on</strong>tinue <str<strong>on</strong>g>to</str<strong>on</strong>g> operate using inner bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m and DC voids 15<br />
1.3.2 Add a list c<strong>on</strong>trol tank <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> port side 17<br />
1.3.3 Move or exchange compartment spaces 18<br />
1.3.4 C<strong>on</strong>vert a current DC void(s) <str<strong>on</strong>g>to</str<strong>on</strong>g> a JP-5 tank(s) and pump last 18<br />
1.3.5 Future ship alterati<strong>on</strong>s and modificati<strong>on</strong>s 18<br />
1.3.6 Re-examine current <str<strong>on</strong>g>List</str<strong>on</strong>g> C<strong>on</strong>trol System 19<br />
1.3.7 Ballast Additi<strong>on</strong> 21<br />
1.3.7.1 Water Ballast 21<br />
1.3.7.2 Solid Ballast 21<br />
1.4 Opti<strong>on</strong> Selecti<strong>on</strong> 23<br />
2.0 Preliminary Analysis and Results 23<br />
2.1 Tank Selecti<strong>on</strong> 24<br />
2.2 Modeling Analysis Performed 25<br />
2.3 Preliminary Decisi<strong>on</strong>-Making Cost Estimati<strong>on</strong> 31<br />
2.4 Structural Analysis 35<br />
2.4.1 Structural Modificati<strong>on</strong>s 39<br />
2.4.1.1 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'* Deck 39<br />
2.4.1.2 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4"" Deck 41<br />
2.4.1.3 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 8* Deck 43<br />
3.0 Final Analysis and Results 44<br />
3.1 Final POSSE Results 45<br />
3.2 Final Cost Estimati<strong>on</strong> 46<br />
3.2.1 Ease of Removal 48<br />
3.2.2 Evidence Perma Ballast® is n<strong>on</strong>-corrosive 48<br />
4.0 C<strong>on</strong>clusi<strong>on</strong> 50<br />
5.0 Recommendati<strong>on</strong>s 51<br />
References 53
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Figures<br />
Figure 1: Stresses in rectangular plates under uniform lateral pressure [2] 38<br />
Figure 2: 2"^* Deck Compartment 2-165-8-V 39<br />
Figure 3: 2"'' Deck Compartment 2-165-8-V, transverse secti<strong>on</strong> 41<br />
Figure 4: 4"" Deck Compartment 4-165-4-V 42<br />
Figure 5: S'*" Deck Compartment 8-225-6-V 43<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Tables<br />
Table 1: CVN 68 <strong>Class</strong> Delivery Data and <strong>Class</strong> Predicti<strong>on</strong>s as of 11/17/03 8<br />
Table 2: Deck Locati<strong>on</strong> Cost Comparis<strong>on</strong> 32<br />
Table 3: Required Structural Modificati<strong>on</strong>s for 2-165-8-V 40<br />
Table 4: Required Structural Modificati<strong>on</strong>s for 4-165-4-V 42<br />
Table 5: Required Structural Modificati<strong>on</strong>s for 8-225-6-V 44<br />
Table 6: Final Cost, Weight Additi<strong>on</strong>, and Change in KG Comparis<strong>on</strong> 47<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> of Appendices<br />
Appendix A: Tank Locati<strong>on</strong> Study 54<br />
Appendix B: Preliminary POSSE Modeling Results 58<br />
Appendix C: Preliminary Cost Estimati<strong>on</strong> Data and Worksheets 62<br />
Appendix D: Preliminary Cost Comparis<strong>on</strong> 86<br />
Appendix E: Complete Structural Analysis 88<br />
Appendix F: Final POSSE Modeling Results 148<br />
Appendix G: Final Cost Estimati<strong>on</strong> Data and Worksheets 150
1.0 Introducti<strong>on</strong><br />
1.1 Motivati<strong>on</strong><br />
<strong>Aircraft</strong> carriers are <str<strong>on</strong>g>the</str<strong>on</strong>g> largest combatant ships in <str<strong>on</strong>g>the</str<strong>on</strong>g> world. They are huge floating<br />
cities, carrying thousands of sailors and aircraft, each vessel with more military power than many<br />
nati<strong>on</strong>s. But with such might comes mighty operati<strong>on</strong>al requirements.<br />
In order <str<strong>on</strong>g>to</str<strong>on</strong>g> launch and recover aircraft <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> flight deck, most ships will report any<br />
change in list in excess of V4 degree <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Engineering Officer of <str<strong>on</strong>g>the</str<strong>on</strong>g> Watch (EOOW) for<br />
correcti<strong>on</strong>. The <strong>Nimitz</strong> class aircraft carrier was designed <str<strong>on</strong>g>to</str<strong>on</strong>g> maintain a level deck during flight<br />
operati<strong>on</strong>s through <str<strong>on</strong>g>the</str<strong>on</strong>g> utilizati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS. The LCS is designed <str<strong>on</strong>g>to</str<strong>on</strong>g> compensate for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
operati<strong>on</strong>al effects of aircraft movement <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> flight deck and in <str<strong>on</strong>g>the</str<strong>on</strong>g> hangar bays and not<br />
intended <str<strong>on</strong>g>to</str<strong>on</strong>g> compensate for an inherent list. Any inherent list imposes operati<strong>on</strong>al c<strong>on</strong>straints <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ship, particularly when <str<strong>on</strong>g>the</str<strong>on</strong>g> carrier has embarked a full air-wing and full fuel loading (Combat<br />
Load C<strong>on</strong>diti<strong>on</strong>). <strong>Nimitz</strong> class carriers have a his<str<strong>on</strong>g>to</str<strong>on</strong>g>ry of inherent starboard list, due primarily <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ship's c<strong>on</strong>figurati<strong>on</strong>. His<str<strong>on</strong>g>to</str<strong>on</strong>g>ry shows that modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class are have increased<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> inherent starboard list of each carrier. This <str<strong>on</strong>g>the</str<strong>on</strong>g>sis will explore various opti<strong>on</strong>s for finding a<br />
permanent soluti<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class list c<strong>on</strong>trol issues, particularly, <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong> of solid<br />
ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> counter list.<br />
1.2 Background<br />
There are a number of obstacles in finding a permanent soluti<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list<br />
associated with most <strong>Nimitz</strong> class carriers, as each carrier has a different inherent list associated<br />
with it. This may sound strange, but every ship is slightly different. The ships are so large and<br />
have such a high procurement cost that <strong>on</strong>ly <strong>on</strong>e is built at a time. It takes an average of five<br />
years <str<strong>on</strong>g>to</str<strong>on</strong>g> build <strong>on</strong>e carrier, and in that time, modernizati<strong>on</strong>s, upgrades, and improvements are
introduced in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> design. As such, <str<strong>on</strong>g>the</str<strong>on</strong>g> ships are c<strong>on</strong>stantly changing and evolving, all within<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> same skin designed in <str<strong>on</strong>g>the</str<strong>on</strong>g> late 1960's. A comparative analysis of <str<strong>on</strong>g>the</str<strong>on</strong>g> commissi<strong>on</strong>ed and<br />
predicted current displacement, vertical center of gravity (KG), and list with <str<strong>on</strong>g>the</str<strong>on</strong>g> latest unknown<br />
growth correcti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class aircraft carriers are shown in Table 1.<br />
Table 1: CVN 68 <strong>Class</strong> Delivery Data and <strong>Class</strong> Predicti<strong>on</strong>s as of 11/17/03<br />
Delivery<br />
Displacement<br />
(I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns)<br />
Predicted<br />
Current<br />
Displacement<br />
(I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns)<br />
Predicted<br />
Current<br />
KG (ft)<br />
Delivery<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g><br />
(degrees)<br />
Predicted<br />
Current<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g><br />
(degrees)<br />
Delivery<br />
Ship<br />
KG (ft)<br />
68 93,283 100,064 45.73 47.22 l.Ol(S) 0.10 (S)<br />
69 93,832 100,588 45.94 47.1 0.82 (S) 0.25 (S)<br />
70 94,069 100,599 46.29 47.28 1.22 (S) 0.11 (P)<br />
71 96,865 103,700 46.4 47.27 0.27 (S) 0.41 (S)<br />
72 97,497 103,912 46.61 47.2 0.77 (S) 1.81 (S)<br />
73 97,816 104,095 46.54 47.03 0.85 (S) 1.55 (S)<br />
74 97,490 103,419 46.63 47.23 1.63 (S) 2.54 (S)<br />
75 97,944 103,863 46.4 46.93 0.43 (S) 1.61 (S)<br />
76 97,953 101,187 46.66 46.77 0.08 (S) 0.99 (S)<br />
#<br />
<strong>Nimitz</strong> class carrier c<strong>on</strong>tracts require that an Accepted Weight Estimate (AWE) be<br />
negotiated between <str<strong>on</strong>g>the</str<strong>on</strong>g> C<strong>on</strong>trac<str<strong>on</strong>g>to</str<strong>on</strong>g>r and <str<strong>on</strong>g>the</str<strong>on</strong>g> Government. A starboard inherent list was seen<br />
creeping upwards through CVN 73, such that for <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 74/75 c<strong>on</strong>tract, <str<strong>on</strong>g>the</str<strong>on</strong>g> program office<br />
invoked a list <str<strong>on</strong>g>to</str<strong>on</strong>g>lerance of 0.50 degree (P/S) for <str<strong>on</strong>g>the</str<strong>on</strong>g> combat load c<strong>on</strong>diti<strong>on</strong>. As a result of this<br />
new requirement, and beginning with <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 74/75 c<strong>on</strong>tract, <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy and <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trac<str<strong>on</strong>g>to</str<strong>on</strong>g>r<br />
agreed <str<strong>on</strong>g>to</str<strong>on</strong>g> include 850 l<strong>on</strong>g <str<strong>on</strong>g>to</str<strong>on</strong>g>ns of c<strong>on</strong>trac<str<strong>on</strong>g>to</str<strong>on</strong>g>r-c<strong>on</strong>trolled ballast in <str<strong>on</strong>g>the</str<strong>on</strong>g> AWE <str<strong>on</strong>g>to</str<strong>on</strong>g> offset <str<strong>on</strong>g>the</str<strong>on</strong>g> already<br />
projected design inherent starboard list. Before any real ballast was <str<strong>on</strong>g>to</str<strong>on</strong>g> be added <strong>on</strong> CVN 74,<br />
however, <str<strong>on</strong>g>the</str<strong>on</strong>g> program office wanted <str<strong>on</strong>g>to</str<strong>on</strong>g> see if <str<strong>on</strong>g>the</str<strong>on</strong>g>re was indeed a list problem after <str<strong>on</strong>g>the</str<strong>on</strong>g> ship was<br />
delivered and fully loaded. It is at this time that CVN 74 was found <str<strong>on</strong>g>to</str<strong>on</strong>g> a have real inherent<br />
starboard list problem. The identified list problem was resolved by <str<strong>on</strong>g>the</str<strong>on</strong>g> use of fresh water (FW)<br />
ballast. To date, permanent ballast has not been installed <strong>on</strong> any aircraft carrier of <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong>
class. Changes <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 76 design resulted in a reduced starboard list and c<strong>on</strong>sequently <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
c<strong>on</strong>trac<str<strong>on</strong>g>to</str<strong>on</strong>g>r-c<strong>on</strong>trolled ballast included in <str<strong>on</strong>g>the</str<strong>on</strong>g> AWE was reduced <str<strong>on</strong>g>to</str<strong>on</strong>g> 650 l<strong>on</strong>g <str<strong>on</strong>g>to</str<strong>on</strong>g>ns.<br />
From operati<strong>on</strong>al experience, it would be safe <str<strong>on</strong>g>to</str<strong>on</strong>g> say that <str<strong>on</strong>g>the</str<strong>on</strong>g>re is an inherent starboard<br />
list under full fuel load (or virtually full) with <str<strong>on</strong>g>the</str<strong>on</strong>g> airwing embarked and no flight operati<strong>on</strong>s<br />
being c<strong>on</strong>ducted <strong>on</strong> most <strong>Nimitz</strong> class carriers. When all <str<strong>on</strong>g>the</str<strong>on</strong>g> planes are stacked <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> starboard<br />
side and <str<strong>on</strong>g>the</str<strong>on</strong>g> ship has just been refueled, <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS is unable <str<strong>on</strong>g>to</str<strong>on</strong>g> level <str<strong>on</strong>g>the</str<strong>on</strong>g> deck. This is when it has<br />
become necessary for some carriers <str<strong>on</strong>g>to</str<strong>on</strong>g> use fresh water ballast in a number of inner bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m voids<br />
and damage c<strong>on</strong>trol (DC) voids <str<strong>on</strong>g>to</str<strong>on</strong>g> correct <str<strong>on</strong>g>the</str<strong>on</strong>g> adverse list c<strong>on</strong>diti<strong>on</strong>. But from a ship<br />
survivability standpoint, and as <str<strong>on</strong>g>the</str<strong>on</strong>g>ir name implies, DC voids are not an acceptable list c<strong>on</strong>trol<br />
measure under normal operating c<strong>on</strong>diti<strong>on</strong>s. Maintaining liquid ballast in DC voids reduces <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
design counter flooding capability of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship. N<strong>on</strong>e <str<strong>on</strong>g>the</str<strong>on</strong>g> less, this is how some ships operate in<br />
order <str<strong>on</strong>g>to</str<strong>on</strong>g> keep <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class ships at sea.<br />
In February 1999, PEO <strong>Carriers</strong> issued a Message <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 68 <strong>Class</strong> identifying<br />
several voids (i.e., n<strong>on</strong> DC voids) that could be used for FW ballasting for ships experiencing list<br />
c<strong>on</strong>trol problems. Prior <str<strong>on</strong>g>to</str<strong>on</strong>g> using those voids, however, <str<strong>on</strong>g>the</str<strong>on</strong>g> message requested <str<strong>on</strong>g>the</str<strong>on</strong>g> ships <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
c<strong>on</strong>firm that <str<strong>on</strong>g>the</str<strong>on</strong>g> list c<strong>on</strong>trol difficulties were not <str<strong>on</strong>g>the</str<strong>on</strong>g> result of abnormal LCS operati<strong>on</strong>s or<br />
adverse liquid loading or s<str<strong>on</strong>g>to</str<strong>on</strong>g>res management. <strong>Carriers</strong> experiencing list c<strong>on</strong>trol difficulties were<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> request approval from <str<strong>on</strong>g>the</str<strong>on</strong>g> Type Commander (TYCOM) <str<strong>on</strong>g>to</str<strong>on</strong>g> fill <str<strong>on</strong>g>the</str<strong>on</strong>g> voids listed in <str<strong>on</strong>g>the</str<strong>on</strong>g> message.<br />
The approval would remain in effect for that ship until a permanent soluti<strong>on</strong> was identified and<br />
implemented.<br />
It is obvious that fixing <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list cannot be solved by leaving aircraft behind or by<br />
limiting <str<strong>on</strong>g>the</str<strong>on</strong>g> load of fuel carried. TYCOM directive states that <str<strong>on</strong>g>the</str<strong>on</strong>g> JP-5 system is required <str<strong>on</strong>g>to</str<strong>on</strong>g>
emain at least 60% full at all times. These ships have a very specific warfighting requirement<br />
that must be achieved, and a reducti<strong>on</strong> in capabilities is unacceptable.<br />
There must be a soluti<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list problem bey<strong>on</strong>d limiting ships payload or<br />
using <str<strong>on</strong>g>the</str<strong>on</strong>g> DC voids outside of <str<strong>on</strong>g>the</str<strong>on</strong>g>ir designed intent. This report evaluates o<str<strong>on</strong>g>the</str<strong>on</strong>g>r alternatives <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
finding a soluti<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> fix <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <strong>Nimitz</strong> class aircraft carriers.<br />
1.2.1 Past Research<br />
A <str<strong>on</strong>g>the</str<strong>on</strong>g>sis was performed in 2001 by Michael Mal<strong>on</strong>e, a graduate of MIT. His <str<strong>on</strong>g>the</str<strong>on</strong>g>sis, titled<br />
"An Alternate Method for <str<strong>on</strong>g>the</str<strong>on</strong>g> Determinati<strong>on</strong> of <strong>Aircraft</strong> Carrier Limiting Displacement for<br />
Strength;" determined that although all <strong>Nimitz</strong> class aircraft carriers are approaching <str<strong>on</strong>g>the</str<strong>on</strong>g>ir<br />
limiting displacement for strength, <str<strong>on</strong>g>the</str<strong>on</strong>g> traditi<strong>on</strong>al methods of such calculati<strong>on</strong>s are c<strong>on</strong>servative.<br />
In fact, <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers can accommodate more weight than previously thought.<br />
Because of this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis, <str<strong>on</strong>g>the</str<strong>on</strong>g> U.S. Navy <strong>Aircraft</strong> Carrier Program Office (PMS 312) later directed<br />
N.S. NAPPI Associates <str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>duct a detailed analysis <strong>on</strong> estimating <str<strong>on</strong>g>the</str<strong>on</strong>g> limiting displacement for<br />
strength. Again, it was proven that <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class hull is capable of sustaining additi<strong>on</strong>al<br />
weights which would exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> current established limiting displacement for strength.<br />
1.2.2 Stability<br />
The stability status for USN ships is defined in [4] and is supported by [11]. The Chief of<br />
Naval Operati<strong>on</strong>s has directed that <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy's ships will be kept within naval architectural limits<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> ensure that essential survivability features are maintained. For each ship class, <str<strong>on</strong>g>the</str<strong>on</strong>g> Naval Sea<br />
Systems Command's Weights and Stability Divisi<strong>on</strong> is <str<strong>on</strong>g>to</str<strong>on</strong>g> keep track of <str<strong>on</strong>g>the</str<strong>on</strong>g> weight and stability<br />
status, limiting draft and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r limitati<strong>on</strong>s including being an advocate for weight and moment<br />
status and moment compensati<strong>on</strong> necessary <str<strong>on</strong>g>to</str<strong>on</strong>g> adhere <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> established limits. Surface ships are<br />
10
classified in<str<strong>on</strong>g>to</str<strong>on</strong>g> four status c<strong>on</strong>diti<strong>on</strong>s for vertical center of gravity (KG) and limiting drafts. As<br />
specified in [4], <str<strong>on</strong>g>the</str<strong>on</strong>g> definiti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> status listings are:<br />
• STATUS 1 An increase in weight and a rise of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's center of gravity are<br />
acceptable. Added weight and moment resulting from changes will not require any<br />
compensati<strong>on</strong> unless <str<strong>on</strong>g>the</str<strong>on</strong>g> magnitude of <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong>s is so large as <str<strong>on</strong>g>to</str<strong>on</strong>g> make <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
approach stability limits.<br />
• STATUS 2<br />
accepted.<br />
Nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r an increase in weight nor a rise of a ship's center of gravity can be<br />
• STATUS 3 An increase in <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's weight is acceptable, but a rise of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's center<br />
of gravity must be avoided.<br />
• STATUS 4 A rise of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's center of gravity is acceptable, but increase in weight<br />
must be avoided. Compensati<strong>on</strong> for added weight may be obtained by removal of an<br />
equal or greater weight at any level.<br />
Status 1 is <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly acceptable ship status. The goal is for ships in <str<strong>on</strong>g>the</str<strong>on</strong>g> fleet <str<strong>on</strong>g>to</str<strong>on</strong>g> remain in<br />
Status 1. In <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r three status c<strong>on</strong>diti<strong>on</strong>s, <str<strong>on</strong>g>the</str<strong>on</strong>g> displacement and KG must be closely<br />
m<strong>on</strong>i<str<strong>on</strong>g>to</str<strong>on</strong>g>red <str<strong>on</strong>g>to</str<strong>on</strong>g> ensure <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>diti<strong>on</strong> does not worsen and steps must be taken <str<strong>on</strong>g>to</str<strong>on</strong>g> try <str<strong>on</strong>g>to</str<strong>on</strong>g> bring <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ship back within acceptable design limits. Typically, when an in-service carrier requires a<br />
modificati<strong>on</strong> that will add weight <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship, it is <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>sibility of <str<strong>on</strong>g>the</str<strong>on</strong>g> program office and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
planning yard <str<strong>on</strong>g>to</str<strong>on</strong>g> put <str<strong>on</strong>g>to</str<strong>on</strong>g>ge<str<strong>on</strong>g>the</str<strong>on</strong>g>r a package that includes maintenance and repair items, as well as<br />
modernizati<strong>on</strong> changes. First, a preliminary weight estimate of <str<strong>on</strong>g>the</str<strong>on</strong>g> modernizati<strong>on</strong> changes are<br />
put <str<strong>on</strong>g>to</str<strong>on</strong>g>ge<str<strong>on</strong>g>the</str<strong>on</strong>g>r in <str<strong>on</strong>g>the</str<strong>on</strong>g> package and made ready for installati<strong>on</strong>. Once <str<strong>on</strong>g>the</str<strong>on</strong>g> package is installed, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
planning yard or shipyard keeps track of <str<strong>on</strong>g>the</str<strong>on</strong>g> weights being installed. At <str<strong>on</strong>g>the</str<strong>on</strong>g> end of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
availability, an actual weight report for <str<strong>on</strong>g>the</str<strong>on</strong>g> installed changes is generated. This report is passed<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> shipyard <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> program office where it is incorporated in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> stability baseline of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
pertinent ship.<br />
11
For any c<strong>on</strong>figurati<strong>on</strong> changes, such as adding weight <str<strong>on</strong>g>to</str<strong>on</strong>g> a carrier in Stability Status 2, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
interested party fills out a Justificati<strong>on</strong> Cost Form (JCF) with <str<strong>on</strong>g>the</str<strong>on</strong>g> weight and KG impact as well<br />
as <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's Stability Status. A C<strong>on</strong>figurati<strong>on</strong> C<strong>on</strong>trol Board that includes <str<strong>on</strong>g>the</str<strong>on</strong>g> Program Office,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Ship Design Manager, and <str<strong>on</strong>g>the</str<strong>on</strong>g> necessary Technical Authorities <str<strong>on</strong>g>the</str<strong>on</strong>g>n meet <str<strong>on</strong>g>to</str<strong>on</strong>g> approve or<br />
disapprove <str<strong>on</strong>g>the</str<strong>on</strong>g> modificati<strong>on</strong>. If approved, an Engineering Change Proposal (ECP) for newly<br />
commissi<strong>on</strong>ed ships or a Ship Alterati<strong>on</strong> Request (SAR) for in-service ships is <str<strong>on</strong>g>the</str<strong>on</strong>g>n generated.<br />
The <strong>Nimitz</strong> class was assigned <str<strong>on</strong>g>to</str<strong>on</strong>g> Stability Status 2 by <str<strong>on</strong>g>the</str<strong>on</strong>g> Weight C<strong>on</strong>trol and Stability<br />
Divisi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> Naval Sea Systems Command. This was d<strong>on</strong>e as a result of <str<strong>on</strong>g>the</str<strong>on</strong>g> stability reanalysis<br />
performed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers. The re-analysis revealed <str<strong>on</strong>g>the</str<strong>on</strong>g> following:<br />
• The originally calculated Allowable KG of 48.50 feet was no l<strong>on</strong>ger applicable for this<br />
class of ships. While 48.50 feet is no l<strong>on</strong>ger <str<strong>on</strong>g>the</str<strong>on</strong>g> allowable KG value, it c<strong>on</strong>tinues <str<strong>on</strong>g>to</str<strong>on</strong>g> be<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> KG compara<str<strong>on</strong>g>to</str<strong>on</strong>g>r for CVN 68 - 77 for c<strong>on</strong>tractual reas<strong>on</strong>s.<br />
• The actual damage capability of this class of carriers is not as originally calculated.<br />
• The damage capability of this class decreases as displacement increases.<br />
• It is important for <str<strong>on</strong>g>the</str<strong>on</strong>g> holding bulkhead <str<strong>on</strong>g>to</str<strong>on</strong>g> remain intact.<br />
• The 40'-l 1" limiting draft is based <strong>on</strong> ship geometry limitati<strong>on</strong>s.<br />
As a result of <str<strong>on</strong>g>the</str<strong>on</strong>g> above study, it was determined by that a stability status of 2 should<br />
c<strong>on</strong>tinue <str<strong>on</strong>g>to</str<strong>on</strong>g> be assigned <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class in order <str<strong>on</strong>g>to</str<strong>on</strong>g>:<br />
o C<strong>on</strong>trol <str<strong>on</strong>g>the</str<strong>on</strong>g> displacement growth of <str<strong>on</strong>g>the</str<strong>on</strong>g> class even though some ships are<br />
substantially below <str<strong>on</strong>g>the</str<strong>on</strong>g> displacement associated with <str<strong>on</strong>g>the</str<strong>on</strong>g> limiting draft. This is an<br />
acknowledgement that an increased displacement degrades damage stability<br />
capability.<br />
12
o C<strong>on</strong>trol <str<strong>on</strong>g>the</str<strong>on</strong>g> KG growth of <str<strong>on</strong>g>the</str<strong>on</strong>g> class even though some ships were substantially<br />
below <str<strong>on</strong>g>the</str<strong>on</strong>g> KG compara<str<strong>on</strong>g>to</str<strong>on</strong>g>r of 48.50 feet. This is an acknowledgement that an<br />
increased KG degrades damage stability capability.<br />
1.2.3 Survivability<br />
Survivability is defined in [10] as <str<strong>on</strong>g>the</str<strong>on</strong>g> capacity of a ship <str<strong>on</strong>g>to</str<strong>on</strong>g> absorb damage and maintain<br />
missi<strong>on</strong> integrity. Typically, most decisi<strong>on</strong> making regarding survivability is d<strong>on</strong>e during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
early trade-off stages of ship design. As a result, it is imperative that naval architectural<br />
parameters be c<strong>on</strong>sidered over <str<strong>on</strong>g>the</str<strong>on</strong>g> lifetime of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship in order <str<strong>on</strong>g>to</str<strong>on</strong>g> successfully withstand<br />
designated threat levels. Every attempt must be made <str<strong>on</strong>g>to</str<strong>on</strong>g> prevent any degradati<strong>on</strong> of a warship's<br />
ability <str<strong>on</strong>g>to</str<strong>on</strong>g> perform its offensive missi<strong>on</strong>, sustain battle damage, and survive. <strong>Aircraft</strong> carriers are<br />
fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r defined in [10] as 'capital ships' in that <str<strong>on</strong>g>the</str<strong>on</strong>g>y are expected <str<strong>on</strong>g>to</str<strong>on</strong>g> survive more than <strong>on</strong>e<br />
weap<strong>on</strong>s hit and return <str<strong>on</strong>g>to</str<strong>on</strong>g> some level of missi<strong>on</strong> capability. All o<str<strong>on</strong>g>the</str<strong>on</strong>g>r ships are <strong>on</strong>ly expected <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
survive design level damage from a single design level weap<strong>on</strong> or a single peacetime hazard.<br />
Survivability, weap<strong>on</strong>s effects and operati<strong>on</strong>al envir<strong>on</strong>ments are categorized in terms of<br />
three levels of severity. Level I represents <str<strong>on</strong>g>the</str<strong>on</strong>g> least severe envir<strong>on</strong>ment anticipated for a class of<br />
ship, while Level El represents <str<strong>on</strong>g>the</str<strong>on</strong>g> most severe envir<strong>on</strong>ment projected for a combatant battle<br />
group and includes <str<strong>on</strong>g>the</str<strong>on</strong>g>ir ability <str<strong>on</strong>g>to</str<strong>on</strong>g> deal with <str<strong>on</strong>g>the</str<strong>on</strong>g> broad degrading effects of damage from antiship<br />
cruise missiles (ASCM). <strong>Aircraft</strong> carriers and battle force surface combatants are both<br />
c<strong>on</strong>sidered Level III. Therefore, it is imperative that <str<strong>on</strong>g>the</str<strong>on</strong>g>se ships be operated and maintained as<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>y were designed. Any digressi<strong>on</strong> from operati<strong>on</strong>al restricti<strong>on</strong>s and guidelines makes all<br />
analyses irrelevant.<br />
13
1.2.4 Displacement Limits<br />
Because <str<strong>on</strong>g>the</str<strong>on</strong>g>se aircraft carriers are so important and because any reducti<strong>on</strong> in freeboard<br />
will inherently reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> effectiveness of <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>rpedo side protecti<strong>on</strong> system (TSPS), <str<strong>on</strong>g>the</str<strong>on</strong>g>se ships<br />
are usually displacement critical. The limit is typically expressed in terms of <str<strong>on</strong>g>the</str<strong>on</strong>g> Full Load<br />
C<strong>on</strong>diti<strong>on</strong>. Following is <str<strong>on</strong>g>the</str<strong>on</strong>g> criteria Naval Surface Warfare Center (NSWC) Carderock's Weight<br />
C<strong>on</strong>trol and Stability Divisi<strong>on</strong> uses <str<strong>on</strong>g>to</str<strong>on</strong>g> determine displacement limits for aircraft carriers with a<br />
TSPS:<br />
L2.5 KG Limits<br />
• Strength: The displacement, with an assumed l<strong>on</strong>gitudinal weight distributi<strong>on</strong>, at<br />
which <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>gitudinal bending moments caused by a standardized wave will<br />
produce <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum allowable stress in <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's hull girder.<br />
• Speed: The displacement for surface warships at which <str<strong>on</strong>g>the</str<strong>on</strong>g> ships machinery,<br />
operating at a specified percent of maximum available power, will drive <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> original design speed specified by <str<strong>on</strong>g>the</str<strong>on</strong>g> ships characteristics c<strong>on</strong>sidering<br />
power plant, RPM and <str<strong>on</strong>g>to</str<strong>on</strong>g>rque limits.<br />
• TSPS: The maximum draft for a surface warship which prevents <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>p of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
TSPS from being immersed more than a specified amount.<br />
• Subdivisi<strong>on</strong>: The maximum displacement at which a ship with a TSPS will<br />
satisfac<str<strong>on</strong>g>to</str<strong>on</strong>g>rily resist <str<strong>on</strong>g>the</str<strong>on</strong>g> flooding effects of a specified number of <str<strong>on</strong>g>to</str<strong>on</strong>g>rpedo hits or<br />
similar weap<strong>on</strong>s without submerging <str<strong>on</strong>g>the</str<strong>on</strong>g> margin line at <str<strong>on</strong>g>the</str<strong>on</strong>g> bow or <str<strong>on</strong>g>the</str<strong>on</strong>g> stem.<br />
• Damage Stability: The maximum displacement at which a ship with a TSPS will<br />
satisfac<str<strong>on</strong>g>to</str<strong>on</strong>g>rily resist <str<strong>on</strong>g>the</str<strong>on</strong>g> flooding effects of a specified number of <str<strong>on</strong>g>to</str<strong>on</strong>g>rpedo hits or<br />
similar weap<strong>on</strong>s while providing adequate stability <str<strong>on</strong>g>to</str<strong>on</strong>g> resist high static heel<br />
angles, resist capsizing, and return <str<strong>on</strong>g>to</str<strong>on</strong>g> some level of missi<strong>on</strong> capability.<br />
The KG Limit for a warship is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum height of <str<strong>on</strong>g>the</str<strong>on</strong>g> vertical center of gravity of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ship in <str<strong>on</strong>g>the</str<strong>on</strong>g> Full Load c<strong>on</strong>diti<strong>on</strong>. Any Full Load KG below this limit is expected <str<strong>on</strong>g>to</str<strong>on</strong>g> survive <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
hazards of wind, high speed maneuvering or damage, assuming <str<strong>on</strong>g>the</str<strong>on</strong>g> ship follows its liquid<br />
loading instructi<strong>on</strong>s. The Limiting KG is <str<strong>on</strong>g>the</str<strong>on</strong>g> lowest limit of ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r <str<strong>on</strong>g>the</str<strong>on</strong>g> damage stability limit or<br />
14
<str<strong>on</strong>g>the</str<strong>on</strong>g> intact stability limit. Following is <str<strong>on</strong>g>the</str<strong>on</strong>g> DDS-079-1 criteria NSWC Carderock's Weight<br />
C<strong>on</strong>trol and Stability Divisi<strong>on</strong> uses <str<strong>on</strong>g>to</str<strong>on</strong>g> determine stability limits for surface warships with a SPS:<br />
• Intact: 100 Knot Beam Wind - The Full Load KG which will permit <str<strong>on</strong>g>the</str<strong>on</strong>g> ship <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
operate in any normal loading c<strong>on</strong>diti<strong>on</strong> and survive <str<strong>on</strong>g>the</str<strong>on</strong>g> heeling force of a fully<br />
developed hurricane (assumed as a nominal 100 knots). The ship will retain<br />
sufficient stability <str<strong>on</strong>g>to</str<strong>on</strong>g> absorb higher gusts without being knocked over, and <str<strong>on</strong>g>to</str<strong>on</strong>g> absorb<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dynamic effects of wave acti<strong>on</strong> without being rolled over.<br />
• Damage: The Full Load KG Limit for large surface combatants, such as battleships<br />
and aircraft carriers which have a side protective system, is associated with <str<strong>on</strong>g>the</str<strong>on</strong>g> worst<br />
possible combinati<strong>on</strong> of a specified number of hazards (<str<strong>on</strong>g>to</str<strong>on</strong>g>rpedoes/missiles) which<br />
will:<br />
1) Cause <str<strong>on</strong>g>the</str<strong>on</strong>g> ship <str<strong>on</strong>g>to</str<strong>on</strong>g> heel <str<strong>on</strong>g>to</str<strong>on</strong>g> a large initial angle of 15 - 20 degrees,<br />
2) Cause <str<strong>on</strong>g>the</str<strong>on</strong>g> ship <str<strong>on</strong>g>to</str<strong>on</strong>g> approach a capsize situati<strong>on</strong>, or<br />
3) Exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> counter flooding capability <str<strong>on</strong>g>to</str<strong>on</strong>g> return <str<strong>on</strong>g>to</str<strong>on</strong>g> limited operati<strong>on</strong>. Limited<br />
operati<strong>on</strong> is defined as a heel of less than 5 degrees <str<strong>on</strong>g>to</str<strong>on</strong>g> operate aircraft (should be<br />
3 degrees for current aircraft) or less than 10 degrees <str<strong>on</strong>g>to</str<strong>on</strong>g> operate <str<strong>on</strong>g>the</str<strong>on</strong>g> main turrets.<br />
In any of <str<strong>on</strong>g>the</str<strong>on</strong>g> above damage c<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>the</str<strong>on</strong>g> ship must still possess sufficient dynamic<br />
stability <str<strong>on</strong>g>to</str<strong>on</strong>g> resist capsizing moments induced by wind and waves.<br />
1.3 Present Opti<strong>on</strong>s<br />
1.3.1 C<strong>on</strong>tinue <str<strong>on</strong>g>to</str<strong>on</strong>g> operate using inner bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m and DC voids<br />
Any departure from proper design and operati<strong>on</strong>al criteria degrades any analysis<br />
performed. For example, most stability analyses performed assumes that DC voids are used<br />
correctly, <str<strong>on</strong>g>the</str<strong>on</strong>g> ship is <strong>on</strong> an even keel, and that <str<strong>on</strong>g>the</str<strong>on</strong>g> limiting displacement is not exceeded. In fact,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re is an interrelati<strong>on</strong>ship between increasing displacement and a number of fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs, <str<strong>on</strong>g>to</str<strong>on</strong>g> include<br />
ship strength, survivability, stability and seakeeping. Increasing <str<strong>on</strong>g>the</str<strong>on</strong>g> weight, or displacement, of<br />
carriers is a serious c<strong>on</strong>cern because any weight increase <strong>on</strong>ly serves <str<strong>on</strong>g>to</str<strong>on</strong>g> reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> service life of<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ship. It should be noted again that not all carriers use DC voids <str<strong>on</strong>g>to</str<strong>on</strong>g> augment <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS, but it is<br />
also uncertain as <str<strong>on</strong>g>to</str<strong>on</strong>g> how many actually will use <str<strong>on</strong>g>the</str<strong>on</strong>g>m as a last resort.<br />
DC void usage results in a reducti<strong>on</strong> in TSPS defense. The purpose of <str<strong>on</strong>g>the</str<strong>on</strong>g> TSPS <strong>on</strong> any<br />
capital ship is <str<strong>on</strong>g>to</str<strong>on</strong>g> protect <str<strong>on</strong>g>the</str<strong>on</strong>g> vital spaces of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship against flooding and/or de<str<strong>on</strong>g>to</str<strong>on</strong>g>nati<strong>on</strong> of s<str<strong>on</strong>g>to</str<strong>on</strong>g>wed<br />
15
ordnance. Vital spaces include magazine and propulsi<strong>on</strong> system spaces. The TSPS provides <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
desired protecti<strong>on</strong> by being c<strong>on</strong>structed of a series of l<strong>on</strong>gitudinal bulkheads nested transversely.<br />
These l<strong>on</strong>gitudinal spaces are fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r subdivided by transverse fluid-tight bulkheads creating a<br />
'h<strong>on</strong>eycomb' arrangement outboard of <str<strong>on</strong>g>the</str<strong>on</strong>g> vital magazines and machinery spaces. The spaces<br />
thus created between <str<strong>on</strong>g>the</str<strong>on</strong>g> bulkheads are alternately filled with liquids (fuel oil, JP-5, ballast<br />
water, etc.) or are left empty (damage c<strong>on</strong>trol voids). The passive protecti<strong>on</strong> afforded by this<br />
combinati<strong>on</strong> of bulkheads and 'liquid/air layers" serves <str<strong>on</strong>g>to</str<strong>on</strong>g> absorb, deflect and reject <str<strong>on</strong>g>the</str<strong>on</strong>g> explosive<br />
force generated by weap<strong>on</strong>s such as <str<strong>on</strong>g>to</str<strong>on</strong>g>rpedoes or mines. Placing liquid in <str<strong>on</strong>g>the</str<strong>on</strong>g> void layer<br />
combined with an empty liquid layer will be <str<strong>on</strong>g>the</str<strong>on</strong>g> worst-case scenario, while <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r will<br />
result in less of a reducti<strong>on</strong>.<br />
Similarly, DC voids are supposed <str<strong>on</strong>g>to</str<strong>on</strong>g> be used exactly as <str<strong>on</strong>g>the</str<strong>on</strong>g>ir name implies, <str<strong>on</strong>g>to</str<strong>on</strong>g> combat<br />
flooding with <str<strong>on</strong>g>the</str<strong>on</strong>g> ability <str<strong>on</strong>g>to</str<strong>on</strong>g> adjust for list and trim in order <str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>tinue <str<strong>on</strong>g>to</str<strong>on</strong>g> fulfill missi<strong>on</strong><br />
objectives after sustained damage by being able <str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>tinue <str<strong>on</strong>g>to</str<strong>on</strong>g> launch and recover aircraft. The<br />
specified primary purpose of <str<strong>on</strong>g>the</str<strong>on</strong>g> DC voids is for damage c<strong>on</strong>trol. Sea chests and valves for<br />
flooding underwater side protecti<strong>on</strong> system spaces (DC voids) are required <str<strong>on</strong>g>to</str<strong>on</strong>g> flood within six<br />
minutes <str<strong>on</strong>g>to</str<strong>on</strong>g> fill <str<strong>on</strong>g>the</str<strong>on</strong>g> space <str<strong>on</strong>g>to</str<strong>on</strong>g> within 1 foot of <str<strong>on</strong>g>the</str<strong>on</strong>g> full load waterline per secti<strong>on</strong> 529i of [6]. In fact,<br />
current stability criteria require that <str<strong>on</strong>g>the</str<strong>on</strong>g> ship be able <str<strong>on</strong>g>to</str<strong>on</strong>g> counter flood <str<strong>on</strong>g>to</str<strong>on</strong>g> return <str<strong>on</strong>g>the</str<strong>on</strong>g> flight deck <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
within 5 degrees of upright after damage. When a ship has <str<strong>on</strong>g>to</str<strong>on</strong>g> resort <str<strong>on</strong>g>to</str<strong>on</strong>g> maintaining list by<br />
flooding DC voids, <str<strong>on</strong>g>the</str<strong>on</strong>g> crew becomes encumbered by a task that should be unnecessary. The<br />
Damage C<strong>on</strong>trol Assistant (DCA) and EOOW are drawn away from <str<strong>on</strong>g>the</str<strong>on</strong>g>ir normal tasks and in<str<strong>on</strong>g>to</str<strong>on</strong>g><br />
roles as reacti<strong>on</strong>ary problem-solvers, keeping an eye <strong>on</strong> flight deck aircraft placements, fuel tank<br />
levels, and ship list. This is a poor utilizati<strong>on</strong> of manpower, c<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> primary duties of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
DCA and EOOW, which are <str<strong>on</strong>g>the</str<strong>on</strong>g> coordinati<strong>on</strong> of damage c<strong>on</strong>trol acti<strong>on</strong>s and <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>sibility<br />
16
for ships propulsi<strong>on</strong>, respectively. Also, a ship's crew is c<strong>on</strong>tinuously rotating. As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g>re<br />
is a c<strong>on</strong>tinual learning curve that relies <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> passage of operati<strong>on</strong>al knowledge from generati<strong>on</strong><br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> generati<strong>on</strong>. This is not <str<strong>on</strong>g>the</str<strong>on</strong>g> optimal way <str<strong>on</strong>g>to</str<strong>on</strong>g> operate a multi-billi<strong>on</strong> dollar asset, and it is in our<br />
best interest <str<strong>on</strong>g>to</str<strong>on</strong>g> not put <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>us of correcting an evoluti<strong>on</strong>ary design fault <strong>on</strong> a crew who will<br />
serve at most a three year <str<strong>on</strong>g>to</str<strong>on</strong>g>ur. Additi<strong>on</strong>ally, de-ballasting DC voids is extremely time intensive.<br />
If a real casualty was <str<strong>on</strong>g>to</str<strong>on</strong>g> occur with <str<strong>on</strong>g>the</str<strong>on</strong>g> wr<strong>on</strong>g or <str<strong>on</strong>g>to</str<strong>on</strong>g>o many DC voids flooded, <str<strong>on</strong>g>the</str<strong>on</strong>g>re may not be<br />
sufficient time <str<strong>on</strong>g>to</str<strong>on</strong>g> correct <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>diti<strong>on</strong>. It is not hard <str<strong>on</strong>g>to</str<strong>on</strong>g> imagine <str<strong>on</strong>g>the</str<strong>on</strong>g> disastrous results possible.<br />
1.3.2 Add a list c<strong>on</strong>trol tank <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> port side<br />
The c<strong>on</strong>trol of permanent lists (static heel angles) by adding an additi<strong>on</strong>al list c<strong>on</strong>trol tank<br />
of <str<strong>on</strong>g>the</str<strong>on</strong>g> port side could also be c<strong>on</strong>sidered an opti<strong>on</strong>. The LCS is designed <str<strong>on</strong>g>to</str<strong>on</strong>g> compensate for<br />
variable lists generated by load items that are moved about <str<strong>on</strong>g>the</str<strong>on</strong>g> ship over short periods of time.<br />
Such loads could be liquids, cargo, s<str<strong>on</strong>g>to</str<strong>on</strong>g>res, vehicles or aircraft. The current <strong>Nimitz</strong> class LCS<br />
c<strong>on</strong>sists often list c<strong>on</strong>trol tanks, two centrifugal pumps each rated at 1800 gpm at 30 psi, and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
associated piping and valves required <str<strong>on</strong>g>to</str<strong>on</strong>g> compensate for lists up <str<strong>on</strong>g>to</str<strong>on</strong>g> 1.5 degrees in 20 minutes.<br />
The system is designed <str<strong>on</strong>g>to</str<strong>on</strong>g> be filled with seawater (SW) or firemain <str<strong>on</strong>g>to</str<strong>on</strong>g> 50% of its <str<strong>on</strong>g>to</str<strong>on</strong>g>tal capacity of<br />
278,533 gall<strong>on</strong>s. This allows tanks <str<strong>on</strong>g>to</str<strong>on</strong>g> be filled <str<strong>on</strong>g>to</str<strong>on</strong>g> 100% <strong>on</strong> <strong>on</strong>e side while <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r side is left<br />
empty.<br />
The problems encountered with using SW in tanks may be c<strong>on</strong>mi<strong>on</strong> knowledge <str<strong>on</strong>g>to</str<strong>on</strong>g> most<br />
people; however, potential corrosi<strong>on</strong> from using salt water has encouraged some carriers <str<strong>on</strong>g>to</str<strong>on</strong>g> use<br />
potable water (PW) as a means <str<strong>on</strong>g>to</str<strong>on</strong>g> fill <str<strong>on</strong>g>the</str<strong>on</strong>g>ir list c<strong>on</strong>trol tanks. The LCS is designed with PW as a<br />
back-up <str<strong>on</strong>g>to</str<strong>on</strong>g> using SW or firemain. This is advantageous for corrosi<strong>on</strong> issues, but can be a<br />
problem for PW inven<str<strong>on</strong>g>to</str<strong>on</strong>g>ry. Any leaks in <str<strong>on</strong>g>the</str<strong>on</strong>g> system or maintenance requiring system fill and<br />
17
drain could use a large amount of PW. When underway, potable water c<strong>on</strong>servati<strong>on</strong> is of<br />
primary importance.<br />
1.3.3 Move or exchange compartment spaces<br />
Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r opti<strong>on</strong> is <str<strong>on</strong>g>to</str<strong>on</strong>g> move or exchange compartment spaces, such as relocating heavy<br />
equipment <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> starboard side <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> port side and vice versa. The reducti<strong>on</strong> of starboard<br />
moment by <str<strong>on</strong>g>the</str<strong>on</strong>g> removal or relocati<strong>on</strong> of items of lightship weight would reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> quantity of<br />
ballast required, but would be very small by comparis<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> amount of permanent ballast<br />
required. In order <str<strong>on</strong>g>to</str<strong>on</strong>g> achieve <str<strong>on</strong>g>the</str<strong>on</strong>g> necessary list correcti<strong>on</strong>s, an enormous amount of weight<br />
would have <str<strong>on</strong>g>to</str<strong>on</strong>g> be relocated. The costs involved with such an undertaking would be extremely<br />
high.<br />
1.3.4 C<strong>on</strong>vert a current DC void(s) <str<strong>on</strong>g>to</str<strong>on</strong>g> a JP-5 tank(s) and pump last<br />
C<strong>on</strong>verting portside DC floodable voids in<str<strong>on</strong>g>to</str<strong>on</strong>g> fuel tanks is also an opti<strong>on</strong>. This opti<strong>on</strong> will<br />
add <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> overall weight of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship and again a reducti<strong>on</strong> in TSPS capability becomes a large<br />
c<strong>on</strong>cern as liquid is being placed in <str<strong>on</strong>g>the</str<strong>on</strong>g> air layer and thus opening a window of vulnerability.<br />
1.3.5 Future ship alterati<strong>on</strong>s and modiflcati<strong>on</strong>s<br />
It is also possible that future modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class aircraft carrier will serve <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
provide a port list, <str<strong>on</strong>g>the</str<strong>on</strong>g>reby reducing <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent starboard list. Modificati<strong>on</strong>s such as replacing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> existing <strong>Nimitz</strong> class starboard island with <str<strong>on</strong>g>the</str<strong>on</strong>g> new modified CVN 76 island could serve <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> starboard list. In fact, CVN 76 has had so many design changes that its starboard<br />
inherent list is less than <strong>on</strong>e degree, currently based <strong>on</strong> preliminary results of its inclining<br />
experiment. <str<strong>on</strong>g>List</str<strong>on</strong>g> for CVN 76 has not been an issue thus far, however, at <str<strong>on</strong>g>the</str<strong>on</strong>g> time feedback was<br />
gained, <str<strong>on</strong>g>the</str<strong>on</strong>g> ship had not been fully loaded out. CVN 76 is slightly different from <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
<strong>Nimitz</strong> class ships. The weap<strong>on</strong>s eleva<str<strong>on</strong>g>to</str<strong>on</strong>g>r is combined in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> main structure and <str<strong>on</strong>g>the</str<strong>on</strong>g> aft mast is<br />
18
combined with <str<strong>on</strong>g>the</str<strong>on</strong>g> island which is <strong>on</strong>e level shorter. There is also a more realistic protecti<strong>on</strong><br />
scheme such that a space armor c<strong>on</strong>cept was employed. On <str<strong>on</strong>g>the</str<strong>on</strong>g> older islands, such as CVN 73,<br />
Level III protecti<strong>on</strong> can be seen throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> entire island. This includes 40# (1") plating,<br />
whereas <str<strong>on</strong>g>the</str<strong>on</strong>g> new CVN 76 island has Level II protecti<strong>on</strong> in some areas and is thus lighter.<br />
Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r opti<strong>on</strong> could be <str<strong>on</strong>g>to</str<strong>on</strong>g> extend <str<strong>on</strong>g>the</str<strong>on</strong>g> port side flight deck <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> old <strong>Nimitz</strong> class, as<br />
was d<strong>on</strong>e <strong>on</strong> CVN 76. This allowed for more operati<strong>on</strong>al flexibility as <str<strong>on</strong>g>the</str<strong>on</strong>g> forward port jet blast<br />
deflec<str<strong>on</strong>g>to</str<strong>on</strong>g>r can now be used <str<strong>on</strong>g>to</str<strong>on</strong>g> its full extent. In any case, it is important <str<strong>on</strong>g>to</str<strong>on</strong>g> note that any number<br />
of ship alterati<strong>on</strong>s could be made when time and m<strong>on</strong>ey become available in <str<strong>on</strong>g>the</str<strong>on</strong>g> future.<br />
1.3.6 Re-examine current <str<strong>on</strong>g>List</str<strong>on</strong>g> C<strong>on</strong>trol System<br />
Fleet feedback was taken in<str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>siderati<strong>on</strong> when performing this study. The design of<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> current LCS reportedly requires extensive manpower for operati<strong>on</strong>s, possesses obsolete<br />
comp<strong>on</strong>ents, and is not integrated with o<str<strong>on</strong>g>the</str<strong>on</strong>g>r shipboard liquid-movement functi<strong>on</strong>s. The<br />
installed LCS c<strong>on</strong>sists of 10 tanks, 2 pumps and 14 associated valves <str<strong>on</strong>g>to</str<strong>on</strong>g> distribute seawater<br />
ballast as required compensating for lists up <str<strong>on</strong>g>to</str<strong>on</strong>g> 1.5 degrees. The manually c<strong>on</strong>trolled system<br />
uses verbal communicati<strong>on</strong>s and associated sailor acti<strong>on</strong>s for operati<strong>on</strong>.<br />
Much of <str<strong>on</strong>g>the</str<strong>on</strong>g> fleet feedback received noted that <str<strong>on</strong>g>the</str<strong>on</strong>g> current LCS provides sufficient<br />
c<strong>on</strong>trol when <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent starboard list has been corrected. The fleet also noted, however, that if<br />
correcti<strong>on</strong> has not been provided, <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS al<strong>on</strong>e does not provide ample list correcti<strong>on</strong> while at<br />
full combat load (average displacement between 98,000 and 100,000 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns, mean draft<br />
approximately between 38'10" and 39'10", even liquid distributi<strong>on</strong>, and standard spotting of<br />
aircraft for flight operati<strong>on</strong>s). Standard spotting includes F-18s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 1 and 4 row, hummers<br />
(fleet jarg<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> E-2C Hawkeye) in <str<strong>on</strong>g>the</str<strong>on</strong>g> hummer hole, F-14s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> stem of <str<strong>on</strong>g>the</str<strong>on</strong>g> flight deck.<br />
19
helicopters and C-2 Greyhounds inboard of <str<strong>on</strong>g>the</str<strong>on</strong>g> island, cranes aft of <str<strong>on</strong>g>the</str<strong>on</strong>g> island, and <str<strong>on</strong>g>the</str<strong>on</strong>g> rest of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
aircraft dispersed between <str<strong>on</strong>g>the</str<strong>on</strong>g>m.<br />
The LCS is currently being au<str<strong>on</strong>g>to</str<strong>on</strong>g>mated via <str<strong>on</strong>g>the</str<strong>on</strong>g> Au<str<strong>on</strong>g>to</str<strong>on</strong>g>mated <str<strong>on</strong>g>List</str<strong>on</strong>g> C<strong>on</strong>trol System alterati<strong>on</strong><br />
(ALCS 9145K). The ALCS provides remote c<strong>on</strong>trol and m<strong>on</strong>i<str<strong>on</strong>g>to</str<strong>on</strong>g>ring of <str<strong>on</strong>g>the</str<strong>on</strong>g> aircraft carrier LCS<br />
from Damage C<strong>on</strong>trol Central (DCC) and Shaft Alley via a flat panel display. Four existing loop<br />
valves are upgraded from manual <str<strong>on</strong>g>to</str<strong>on</strong>g> mo<str<strong>on</strong>g>to</str<strong>on</strong>g>r operated and are integrated in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol system.<br />
Existing pump c<strong>on</strong>trollers are replaced and c<strong>on</strong>trol of pumps, valves and tank level m<strong>on</strong>i<str<strong>on</strong>g>to</str<strong>on</strong>g>ring<br />
are integrated in<str<strong>on</strong>g>to</str<strong>on</strong>g> a single system with redundant capabilities. The ALCS utilizes commercialoff-<str<strong>on</strong>g>the</str<strong>on</strong>g>-shelf<br />
comp<strong>on</strong>ents and Navy-owned software <str<strong>on</strong>g>to</str<strong>on</strong>g> decrease <str<strong>on</strong>g>the</str<strong>on</strong>g> manpower needed for<br />
operati<strong>on</strong> and maintenance, increase au<str<strong>on</strong>g>to</str<strong>on</strong>g>mati<strong>on</strong>, reduce life cycle costs and significantly<br />
improve system reliability. System line-up and tank management is au<str<strong>on</strong>g>to</str<strong>on</strong>g>mated and managed<br />
such that tanks can be filled faster, utilizing fewer watchstanders and increasing system<br />
efficiency. C<strong>on</strong>trol and m<strong>on</strong>i<str<strong>on</strong>g>to</str<strong>on</strong>g>ring of <str<strong>on</strong>g>the</str<strong>on</strong>g> LCS is performed from two human-machine interface<br />
(HMI) stati<strong>on</strong>s: <strong>on</strong>e in DCC and <strong>on</strong>e in Shaft Alley. The system can also be operated from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Central C<strong>on</strong>trol Stati<strong>on</strong>, and operates in both remote and semi-au<str<strong>on</strong>g>to</str<strong>on</strong>g>matic modes.<br />
Very little feedback has been obtained regarding <str<strong>on</strong>g>the</str<strong>on</strong>g> new ALCS and its improvements <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
overall ship operati<strong>on</strong>s. To date, installati<strong>on</strong> has been completed <strong>on</strong> three of <str<strong>on</strong>g>the</str<strong>on</strong>g> ten planned<br />
carriers. Although <str<strong>on</strong>g>the</str<strong>on</strong>g> system provides <str<strong>on</strong>g>the</str<strong>on</strong>g> means <str<strong>on</strong>g>to</str<strong>on</strong>g> au<str<strong>on</strong>g>to</str<strong>on</strong>g>matically operate pumps and valves,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> capacity of <str<strong>on</strong>g>the</str<strong>on</strong>g> system has not been changed. To really affect <str<strong>on</strong>g>the</str<strong>on</strong>g> starboard inherent list,<br />
more ballasting is going <str<strong>on</strong>g>to</str<strong>on</strong>g> be required. Once <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent starboard list is fixed, <str<strong>on</strong>g>the</str<strong>on</strong>g> ALCS will<br />
be extremely advantageous <str<strong>on</strong>g>to</str<strong>on</strong>g> overall carrier operati<strong>on</strong>s.<br />
20
1.3.7 Ballast Additi<strong>on</strong><br />
1.3.7.1 Water Ballast<br />
Special preparati<strong>on</strong> would be required for all tanks or voids using locked-in water ballast<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> correct <str<strong>on</strong>g>the</str<strong>on</strong>g> starboard inherent list. The sp<strong>on</strong>s<strong>on</strong> voids, in particular, are coated with epoxy over<br />
an inorganic zinc primer; this is suitable for installati<strong>on</strong> of water ballast, but <strong>on</strong>ly for a period of<br />
up <str<strong>on</strong>g>to</str<strong>on</strong>g> five years if it is intact. Preparati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> sp<strong>on</strong>s<strong>on</strong> voids for installati<strong>on</strong> of water would<br />
require inspecti<strong>on</strong> and possibly repair of <str<strong>on</strong>g>the</str<strong>on</strong>g> existing coating systems. Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r problem with<br />
using water as a source of ballast is that it is difficult <str<strong>on</strong>g>to</str<strong>on</strong>g> provide a sufficient amount of water<br />
ballast in a space judicious manner in order <str<strong>on</strong>g>to</str<strong>on</strong>g> provide enough permanent list correcti<strong>on</strong>.<br />
Although water is an inexpensive material, utilities would have <str<strong>on</strong>g>to</str<strong>on</strong>g> be relocated <str<strong>on</strong>g>to</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r spaces<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks <str<strong>on</strong>g>the</str<strong>on</strong>g>mselves cannot be partially filled.<br />
1.3.7.2 Solid Ballast<br />
For purposes of this project, lead was not c<strong>on</strong>sidered as an opti<strong>on</strong> due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tremendous<br />
handling expenses and associated carcinogenic problems. Instead, a pumpable slurry of ir<strong>on</strong>-ore,<br />
known as Perma Ballast®, was examined as a possible source of solid ballast. Ballast<br />
Technologies Inc. (BTI) has been a provider and installer of Perma Ballast® since 1983. Their<br />
product is widely acknowledged <str<strong>on</strong>g>to</str<strong>on</strong>g> be <str<strong>on</strong>g>the</str<strong>on</strong>g> quickest and most cost-effective method of ballast<br />
installati<strong>on</strong>. All materials, including <str<strong>on</strong>g>the</str<strong>on</strong>g> fluid used <str<strong>on</strong>g>to</str<strong>on</strong>g> install <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast, are naturally occurring,<br />
n<strong>on</strong><str<strong>on</strong>g>to</str<strong>on</strong>g>xic, n<strong>on</strong>-corrosive and envir<strong>on</strong>mentally safe. No gases or vapors are generated and no<br />
special handling is required up<strong>on</strong> installati<strong>on</strong> or removal.<br />
Minimal vessel modificati<strong>on</strong> is required <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship, <str<strong>on</strong>g>the</str<strong>on</strong>g>reby providing savings <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
shipyard. Jobs are not generally subc<strong>on</strong>tracted out, <str<strong>on</strong>g>the</str<strong>on</strong>g>reby cutting out <str<strong>on</strong>g>the</str<strong>on</strong>g> middle man and<br />
making this product more competitive. Prior <str<strong>on</strong>g>to</str<strong>on</strong>g> installati<strong>on</strong>, engineers and key pers<strong>on</strong>nel inspect<br />
21
<str<strong>on</strong>g>the</str<strong>on</strong>g> vessel <str<strong>on</strong>g>to</str<strong>on</strong>g> be ballasted and its locati<strong>on</strong>. Requirements such as electrical, water, compressed<br />
air, and equipment locati<strong>on</strong> are assessed. BTI engineers <str<strong>on</strong>g>the</str<strong>on</strong>g>n submit engineered drawings noting<br />
locati<strong>on</strong> of equipment and diagrams of <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong> system al<strong>on</strong>g with a written operating plan<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> project. BTI uses its own experienced pers<strong>on</strong>nel and equipment during ballast<br />
installati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> ensure safe, rapid and efficient mobilizati<strong>on</strong>, installati<strong>on</strong>, and demobilizati<strong>on</strong>.<br />
BTI's ballast materials are mixed with water and pumped <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> vessel via a combinati<strong>on</strong><br />
of rigid and flexible pipes. The slurry is pumped in at a c<strong>on</strong>trolled velocity in order <str<strong>on</strong>g>to</str<strong>on</strong>g> assure an<br />
even distributi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast around projecti<strong>on</strong>s, pipe, and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r objects, leaving no voids.<br />
Excess water is removed as <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast is installed and settles. This ensures that <str<strong>on</strong>g>the</str<strong>on</strong>g> in-place,<br />
fixed ballast is a dense mass which will not move or shift. Due <str<strong>on</strong>g>to</str<strong>on</strong>g> BTI's materials and placement<br />
method, no special handling or tank modificati<strong>on</strong>s are required.<br />
BTI pretests materials in its labora<str<strong>on</strong>g>to</str<strong>on</strong>g>ry <str<strong>on</strong>g>to</str<strong>on</strong>g> ensure proper density and uniformity.<br />
C<strong>on</strong>tinuous testing is performed during ballast installati<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> verify installed density. Densities<br />
of materials range from 1501b/ft^ <str<strong>on</strong>g>to</str<strong>on</strong>g> 3501b/ftl All processes and materials used by BTI are<br />
approved by ASTM, ABS, MARAD, U.S. Navy, U.S. Coast Guard, Del Norske Veritas, and<br />
Lloyds. In fact, Perma Ballast® has already been installed <strong>on</strong> a number of naval vessels,<br />
particulariy DDG 73,76, and 77. The reas<strong>on</strong> for installati<strong>on</strong> was <str<strong>on</strong>g>to</str<strong>on</strong>g> correct a Flight II starboard<br />
list. Feedback obtained from <str<strong>on</strong>g>the</str<strong>on</strong>g>se installati<strong>on</strong>s described <str<strong>on</strong>g>the</str<strong>on</strong>g> process as being very smooth and<br />
extremely successful.<br />
There are a number of advantages <str<strong>on</strong>g>to</str<strong>on</strong>g> using this Perma Ballast®. It is possible that Perma<br />
Ballast® will absorb shock over a limited area and serve <str<strong>on</strong>g>to</str<strong>on</strong>g> dampen it. Although <str<strong>on</strong>g>the</str<strong>on</strong>g> individual<br />
particles and <str<strong>on</strong>g>the</str<strong>on</strong>g> water are incompressible, <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast® bed is made up of many very<br />
small particles which are not bound <str<strong>on</strong>g>to</str<strong>on</strong>g>ge<str<strong>on</strong>g>the</str<strong>on</strong>g>r by anything except gravity. There is approximately<br />
22
2% entrained air (by volume) in <str<strong>on</strong>g>the</str<strong>on</strong>g> slurry. Some of this air probably remains in <str<strong>on</strong>g>the</str<strong>on</strong>g> slurry after<br />
settling so it would be fair <str<strong>on</strong>g>to</str<strong>on</strong>g> say that Perma Ballast® c<strong>on</strong>tains about 1-2% (by volume)<br />
compressible comp<strong>on</strong>ents. Water is removed as <str<strong>on</strong>g>the</str<strong>on</strong>g> material settles, but even after <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma<br />
Ballast® settles, all of <str<strong>on</strong>g>the</str<strong>on</strong>g> voids between particles are filled by water. In fact, a settled bed of<br />
Perma Ballast® is an extremely effective barrier against permeati<strong>on</strong> of oxygen - ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
bed or through it.<br />
1.4 Opti<strong>on</strong> Selecti<strong>on</strong><br />
From <str<strong>on</strong>g>the</str<strong>on</strong>g> opti<strong>on</strong>s presented above, <str<strong>on</strong>g>the</str<strong>on</strong>g> choice was made <str<strong>on</strong>g>to</str<strong>on</strong>g> use solid ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> correct <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
starboard inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers. Based <strong>on</strong> ballast density, tank locati<strong>on</strong> and<br />
capacity, ease of ballast installati<strong>on</strong>, minor tank structural modificati<strong>on</strong>s, and a decisi<strong>on</strong> making<br />
cost analysis, <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast® appears <str<strong>on</strong>g>to</str<strong>on</strong>g> be <str<strong>on</strong>g>the</str<strong>on</strong>g> best opti<strong>on</strong> for use in correcting <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent<br />
list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class aircraft carriers and is discussed extensively in Chapter 2.<br />
2.0 Preliminary Analysis and Results<br />
Preliminary analysis began with tank selecti<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> serve as input <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Program of Ship<br />
Salvage and Engineering (POSSE) computer analysis program, discussed later in secti<strong>on</strong> 2.2.<br />
Once tanks were selected for ballasting, a naval architectural analysis using POSSE was<br />
performed for 36 scenarios <str<strong>on</strong>g>to</str<strong>on</strong>g> determine list correcti<strong>on</strong>s. These scenarios encompassed<br />
ballasting <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2°'', 4*, and 8* decks with 200 Ib/ft^ and 325 Ib/ft^ density ballast. Fresh water<br />
was also examined as a possible alternative, but not as extensively as <str<strong>on</strong>g>the</str<strong>on</strong>g> solid ballast opti<strong>on</strong>.<br />
Once a complete set of data was obtained, a decisi<strong>on</strong> making cost analysis was performed. This<br />
cost estimati<strong>on</strong> analysis proved that <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density ballast was <str<strong>on</strong>g>the</str<strong>on</strong>g> best opti<strong>on</strong>. As a result,<br />
all structural analysis was performed using <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density ballast. Once <str<strong>on</strong>g>the</str<strong>on</strong>g> structural<br />
analysis was complete, modeling had <str<strong>on</strong>g>to</str<strong>on</strong>g> be performed again using POSSE. In some cases, a<br />
23
minimum ballast weight was calculated for a particular set of tanks for <str<strong>on</strong>g>the</str<strong>on</strong>g> prescribed design<br />
criteria. Analysis had <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>n be performed again in POSSE with <str<strong>on</strong>g>the</str<strong>on</strong>g>se new ballast weights.<br />
Similarly, some of <str<strong>on</strong>g>the</str<strong>on</strong>g> structural analysis revealed that stiffening was required for plating in<br />
some of <str<strong>on</strong>g>the</str<strong>on</strong>g> tank bulkheads. This required ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r cost assessment be performed in order <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
achieve accurate cost estimati<strong>on</strong>s. So, <strong>on</strong>e can see that this project followed a design spiral<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g>wards <str<strong>on</strong>g>to</str<strong>on</strong>g> determining <str<strong>on</strong>g>the</str<strong>on</strong>g> most cost effective and advantageous solid ballasting soluti<strong>on</strong> for<br />
correcting <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers.<br />
2.1 Tank Selecti<strong>on</strong><br />
Tanks selecti<strong>on</strong> was based <strong>on</strong> locati<strong>on</strong> and those that were available for ballasting based<br />
<strong>on</strong> <strong>Nimitz</strong> class carrier drawings. As menti<strong>on</strong>ed previously, ballasting was accomplished <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
relieve up <str<strong>on</strong>g>to</str<strong>on</strong>g> 3 degrees of list in half degree increments. 30 tanks, primarily in <str<strong>on</strong>g>the</str<strong>on</strong>g> aft/port voids,<br />
have been identified <str<strong>on</strong>g>to</str<strong>on</strong>g> accommodate <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong> of Perma Ballast® with 200 Ib/ft^ and 325<br />
Ib/ftl There are 3 tanks or sp<strong>on</strong>s<strong>on</strong> voids <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"^ deck, 16 tanks <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4*^ deck, and 11 tanks<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 8 deck. The methodology utilized was as follows: <str<strong>on</strong>g>to</str<strong>on</strong>g> correct <str<strong>on</strong>g>the</str<strong>on</strong>g> most list possible<br />
using <str<strong>on</strong>g>the</str<strong>on</strong>g> least weight possible. For example, tanks could have been chosen in <str<strong>on</strong>g>the</str<strong>on</strong>g> order of fill<br />
that were fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r aft <str<strong>on</strong>g>to</str<strong>on</strong>g> assist in trim correcti<strong>on</strong>, but that does not provide <str<strong>on</strong>g>the</str<strong>on</strong>g> best list correcti<strong>on</strong><br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> least weight additi<strong>on</strong>. Trim was, however, taken in<str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>siderati<strong>on</strong> such that any<br />
additi<strong>on</strong> of ballast would not serve <str<strong>on</strong>g>to</str<strong>on</strong>g> increase <str<strong>on</strong>g>the</str<strong>on</strong>g> existing trim c<strong>on</strong>diti<strong>on</strong>. As a result, all<br />
changes in trim are also closely m<strong>on</strong>i<str<strong>on</strong>g>to</str<strong>on</strong>g>red.<br />
Included in Appendix A is a series of tables providing informati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> effects that<br />
each tank would produce if <str<strong>on</strong>g>the</str<strong>on</strong>g> tank was individually filled <str<strong>on</strong>g>to</str<strong>on</strong>g> capacity in a combat load<br />
c<strong>on</strong>diti<strong>on</strong> with fresh water as well as each of <str<strong>on</strong>g>the</str<strong>on</strong>g> two ballast density types, 200 Ib/ft^ and 325<br />
lb/ft. This informati<strong>on</strong> includes:<br />
24
Tank name<br />
Tank volume<br />
Ballast type density<br />
Tank weight<br />
Initial KG<br />
Initial trim<br />
Initial weight<br />
Final KG<br />
Final trim<br />
Final weight<br />
A KG<br />
A trim<br />
A weight<br />
2.2 Modeling Analysis Performed<br />
POSSE was used <str<strong>on</strong>g>to</str<strong>on</strong>g> analyze <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list for <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carrier. POSSE is a<br />
software package of modeling, naval architectural design <str<strong>on</strong>g>to</str<strong>on</strong>g>ols, and intact loading and salvage<br />
analysis <str<strong>on</strong>g>to</str<strong>on</strong>g>ols designed primarily for U.S. Navy salvage resp<strong>on</strong>se. The Modeling and Naval<br />
Architecture modules are Microsoft DOS® applicati<strong>on</strong>s packaged through a Windows interface<br />
called <str<strong>on</strong>g>the</str<strong>on</strong>g> Ship Project Edi<str<strong>on</strong>g>to</str<strong>on</strong>g>r. A plan is <str<strong>on</strong>g>the</str<strong>on</strong>g>n developed so that <str<strong>on</strong>g>the</str<strong>on</strong>g> engineer can evaluate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ship in various c<strong>on</strong>diti<strong>on</strong>s. The collecti<strong>on</strong> of c<strong>on</strong>diti<strong>on</strong>s represents <str<strong>on</strong>g>the</str<strong>on</strong>g> steps in <str<strong>on</strong>g>the</str<strong>on</strong>g> plan <str<strong>on</strong>g>to</str<strong>on</strong>g> assess<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> status of <str<strong>on</strong>g>the</str<strong>on</strong>g> vessel. POSSE provides an efficient means <str<strong>on</strong>g>to</str<strong>on</strong>g> develop plans using a tree<br />
structure <str<strong>on</strong>g>to</str<strong>on</strong>g> allow a hierarchical definiti<strong>on</strong> that permits branching <str<strong>on</strong>g>to</str<strong>on</strong>g> investigate various potential<br />
soluti<strong>on</strong>s. Several branches can be developed and viewed c<strong>on</strong>currently. A c<strong>on</strong>diti<strong>on</strong> represents a<br />
25
particular state of <str<strong>on</strong>g>the</str<strong>on</strong>g> vessel. It includes all load and strength informati<strong>on</strong> associated with that<br />
state. For purposes of this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis, <strong>on</strong>ly intact states were analyzed.<br />
<strong>Aircraft</strong> carrier modeling in POSSE was <str<strong>on</strong>g>to</str<strong>on</strong>g>o cumbersome <str<strong>on</strong>g>to</str<strong>on</strong>g> analyze for <str<strong>on</strong>g>the</str<strong>on</strong>g> original DOS<br />
versi<strong>on</strong>. In fact, any analysis prior <str<strong>on</strong>g>to</str<strong>on</strong>g> this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis would have <str<strong>on</strong>g>to</str<strong>on</strong>g> been d<strong>on</strong>e in secti<strong>on</strong>s. With<br />
POSSE 4.0, <str<strong>on</strong>g>the</str<strong>on</strong>g> complete Microsoft Windows® versi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> secti<strong>on</strong>s were able <str<strong>on</strong>g>to</str<strong>on</strong>g> be combined<br />
in<str<strong>on</strong>g>to</str<strong>on</strong>g> a single ship project (.shp) file using <str<strong>on</strong>g>the</str<strong>on</strong>g> ship project edi<str<strong>on</strong>g>to</str<strong>on</strong>g>r. Once <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 68 <strong>Nimitz</strong> <strong>Class</strong><br />
hull was put <str<strong>on</strong>g>to</str<strong>on</strong>g>ge<str<strong>on</strong>g>the</str<strong>on</strong>g>r, a weight ordinate was entered <str<strong>on</strong>g>to</str<strong>on</strong>g> adjust <str<strong>on</strong>g>the</str<strong>on</strong>g> lightship data so that it<br />
coincided with <str<strong>on</strong>g>the</str<strong>on</strong>g> most recent data available. It has been very difficult <str<strong>on</strong>g>to</str<strong>on</strong>g> determine <str<strong>on</strong>g>the</str<strong>on</strong>g> exact<br />
inherent list that each carrier exhibits when under combat load c<strong>on</strong>diti<strong>on</strong>s due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> "unknown<br />
light ship (LS) growth" associated with each carrier and due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> lack of in-service inclining<br />
experiments performed <strong>on</strong> <strong>Nimitz</strong> class carriers. Unknown LS growth is used <str<strong>on</strong>g>to</str<strong>on</strong>g> term<br />
unattributable changes in displacement and centers of gravity over <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's service life.<br />
Examples of unknown LS growth include but are not limited <str<strong>on</strong>g>to</str<strong>on</strong>g>: unauthorized alterati<strong>on</strong>s or<br />
installati<strong>on</strong>s of equipment, accumulati<strong>on</strong>s of paint, deck covering, dead cable runs, old<br />
foundati<strong>on</strong>s, undocumented c<strong>on</strong>figurati<strong>on</strong> changes affecting weight and KG, and excess and<br />
obsolete repair parts, technical manuals, and paperwork. Naval Sea Systems Command's<br />
Weights and Stability Divisi<strong>on</strong> has recently revised <str<strong>on</strong>g>the</str<strong>on</strong>g> unknown light ship (LS) weight and KG<br />
growth data for CVN 71 through CVN 75 based <strong>on</strong> re-evaluati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> results of <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 71<br />
Actual Operating C<strong>on</strong>diti<strong>on</strong> (AOC) Weight Survey and Displacement Test and <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 68 Post-<br />
Refueling Complex Overhaul (RCOH) inclining experiment.<br />
The CVN 68 inclining experiment was <str<strong>on</strong>g>the</str<strong>on</strong>g> first in-service inclining experiment of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
NIMITZ class in 27 years. The CVN 71 displacement test determined <str<strong>on</strong>g>the</str<strong>on</strong>g> ships displacement<br />
and l<strong>on</strong>gitudinal, transverse but not vertical center of gravity. The CVN 68 post RCOH inclining<br />
26
was successfully performed and <str<strong>on</strong>g>the</str<strong>on</strong>g> results are c<strong>on</strong>sidered <str<strong>on</strong>g>to</str<strong>on</strong>g> be accurate. The results of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
inclining show that <str<strong>on</strong>g>the</str<strong>on</strong>g> ship had an unknown lightship weight growth of 1,818 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns and 0.47 feet<br />
of KG increase. The fully loaded c<strong>on</strong>diti<strong>on</strong> was determined <str<strong>on</strong>g>to</str<strong>on</strong>g> have a displacement of 100,019<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns with a KG of 47.21 feet. This provides 3,781 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns (3.78%) and 1.29 feet KG service life<br />
allowance remaining when compared <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> limiting displacement of 103,800 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns and a KG<br />
compara<str<strong>on</strong>g>to</str<strong>on</strong>g>r value of 48.50 feet.<br />
The following changes were made <str<strong>on</strong>g>to</str<strong>on</strong>g> all stability baselines for CVN 71-75:<br />
• CVN 71<br />
o Increase <str<strong>on</strong>g>the</str<strong>on</strong>g> current LS vertical center of gravity by 0.25 feet <str<strong>on</strong>g>to</str<strong>on</strong>g> account for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
unknown LS KG growth.<br />
• CVN 72-75<br />
o Revise <str<strong>on</strong>g>the</str<strong>on</strong>g> unknown LS weight growth <str<strong>on</strong>g>to</str<strong>on</strong>g> 2,333 l<strong>on</strong>g <str<strong>on</strong>g>to</str<strong>on</strong>g>ns.<br />
o Locate <str<strong>on</strong>g>the</str<strong>on</strong>g> unknown LS weight growth at <str<strong>on</strong>g>the</str<strong>on</strong>g> following centers of gravity:<br />
■ VCG = 60.5 ft<br />
■ LCG = 72.47 ft (A)<br />
■ TCG = 5.62 ft (P)<br />
As a result of this unknown growth, an average <strong>Nimitz</strong> class carrier baseline c<strong>on</strong>diti<strong>on</strong><br />
was modeled in POSSE and used for all analyses. Lightship and Combat Load C<strong>on</strong>diti<strong>on</strong> data<br />
was obtained from <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 72 Weight and Moment Baseline Report. This report is based <strong>on</strong>:<br />
1) CVN 68 post RCOH inclining experiment load out,<br />
2) CVN 71 Actual Operating C<strong>on</strong>diti<strong>on</strong> (AOC) results,<br />
3) CVN 73 <strong>Aircraft</strong>/JP-5 Revisi<strong>on</strong>s,<br />
4) Scheduled Restricted Availabilities (SRAs) actually accomplished.<br />
27
5) <str<strong>on</strong>g>the</str<strong>on</strong>g> latest estimates for next overhaul,<br />
6) <str<strong>on</strong>g>the</str<strong>on</strong>g> latest Availability FYOl Planned Incremental Availability (PIA), and<br />
7) LCS at 50%.<br />
A Lightship C<strong>on</strong>diti<strong>on</strong> of 81,450.69 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns and a Combat Load C<strong>on</strong>diti<strong>on</strong> of 104,263.10<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns were obtained from <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 72 Weight and Moment Baseline report and used for<br />
modeling purposes. These values are from before <str<strong>on</strong>g>the</str<strong>on</strong>g> latest correcti<strong>on</strong> for unknown growth was<br />
applied. Included in Table 1 are <str<strong>on</strong>g>the</str<strong>on</strong>g> current CVN class predicti<strong>on</strong>s with <str<strong>on</strong>g>the</str<strong>on</strong>g> most recent<br />
unknown growth correcti<strong>on</strong>s applied. This is an extremely important chart because it shows<br />
each carrier's delivery data and class predicti<strong>on</strong>s for displacement, KG, and list.<br />
The VCG, LCG, TCG, and volume of each tank being analyzed was <str<strong>on</strong>g>the</str<strong>on</strong>g>n checked and<br />
modified if necessary <str<strong>on</strong>g>to</str<strong>on</strong>g> ensure accurate stability and analytical results. These naval architecture<br />
parameters were checked against <str<strong>on</strong>g>the</str<strong>on</strong>g> compartment and access database for CVN 70. Normally,<br />
<strong>on</strong>e would use <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's lines drawings and develop <str<strong>on</strong>g>the</str<strong>on</strong>g> hull up <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bulkhead and freeboard<br />
decks (i.e. <str<strong>on</strong>g>the</str<strong>on</strong>g> highest level <str<strong>on</strong>g>to</str<strong>on</strong>g> which <str<strong>on</strong>g>the</str<strong>on</strong>g>re will be watertight/structural salvage operati<strong>on</strong>s). On<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> basis of this modeling, <strong>on</strong>e checks <str<strong>on</strong>g>the</str<strong>on</strong>g> hydrostatics and curves of form against <str<strong>on</strong>g>the</str<strong>on</strong>g> builder's<br />
documents <str<strong>on</strong>g>to</str<strong>on</strong>g> determine if <str<strong>on</strong>g>the</str<strong>on</strong>g> hull has been modeled correctly. Any freely flooding area above<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> freeboard deck will generally be left off <str<strong>on</strong>g>the</str<strong>on</strong>g> hull model unless <str<strong>on</strong>g>the</str<strong>on</strong>g> deck is a strength deck (i.e.<br />
part of hull girder bending). The 2"'' deck sp<strong>on</strong>s<strong>on</strong> voids had <str<strong>on</strong>g>to</str<strong>on</strong>g> be added <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> model because<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>y were not included previously and POSSE is normally <strong>on</strong>ly utilized <str<strong>on</strong>g>to</str<strong>on</strong>g> model what is inside<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ship's hull. Builder's lines drawings were not used, however, because salvage and<br />
hydrostatic work was not needed for purposes of this project. Instead, weights and centers were<br />
input <str<strong>on</strong>g>to</str<strong>on</strong>g> model <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 72 data <str<strong>on</strong>g>to</str<strong>on</strong>g> determine and correct <str<strong>on</strong>g>the</str<strong>on</strong>g> ship's list. After careful accounting<br />
28
of each tank's locati<strong>on</strong> was added, verified, or corrected, <str<strong>on</strong>g>the</str<strong>on</strong>g> file was imported in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> POSSE<br />
program so that a combat load could be applied.<br />
The combat load c<strong>on</strong>diti<strong>on</strong> was <str<strong>on</strong>g>the</str<strong>on</strong>g>n modified <str<strong>on</strong>g>to</str<strong>on</strong>g> reflect <str<strong>on</strong>g>the</str<strong>on</strong>g> current CVN 72 baseline<br />
combat load data menti<strong>on</strong>ed previously as c<strong>on</strong>stants in <str<strong>on</strong>g>the</str<strong>on</strong>g> POSSE plan that was newly created.<br />
This includes a correcti<strong>on</strong> for:<br />
1) crew and effects,<br />
2) aviati<strong>on</strong> ammuniti<strong>on</strong>,<br />
3) ship ammuniti<strong>on</strong>,<br />
4) provisi<strong>on</strong>s and s<str<strong>on</strong>g>to</str<strong>on</strong>g>res,<br />
5) general s<str<strong>on</strong>g>to</str<strong>on</strong>g>res,<br />
6) lube oil,<br />
7) potable water,<br />
8) reserve and emergency feed water,<br />
9) oxygen and nitrogen producti<strong>on</strong> plant,<br />
10) JP-5 aviati<strong>on</strong> fuel,<br />
ll)gasohne,<br />
12) aircraft,<br />
13) aviati<strong>on</strong> yellow gear,<br />
14) aviati<strong>on</strong> lube oil,<br />
15) <strong>on</strong>board discharge s<str<strong>on</strong>g>to</str<strong>on</strong>g>rage tanks, and<br />
16) bilge and oily water.<br />
Then, <str<strong>on</strong>g>to</str<strong>on</strong>g> reflect CVN 71 AOC results, a miscellaneous weight correcti<strong>on</strong> fac<str<strong>on</strong>g>to</str<strong>on</strong>g>r was<br />
added at <str<strong>on</strong>g>the</str<strong>on</strong>g> combat load c<strong>on</strong>diti<strong>on</strong> TCG, VCG, and LCG. Now, <str<strong>on</strong>g>the</str<strong>on</strong>g> combat load c<strong>on</strong>diti<strong>on</strong> was<br />
29
accurate and ready for <str<strong>on</strong>g>the</str<strong>on</strong>g> creati<strong>on</strong> of several variant c<strong>on</strong>diti<strong>on</strong>s. Specifically, a c<strong>on</strong>diti<strong>on</strong> for<br />
water ballast, high density ballast (325 Ib/ft^), and low density ballast (200 Ib/ft^) was created.<br />
Included in Appendix B is a series of tables providing POSSE modeling results in a<br />
combat load c<strong>on</strong>diti<strong>on</strong> for list correcti<strong>on</strong> in half degree increments up <str<strong>on</strong>g>to</str<strong>on</strong>g> 3 degrees for fresh water<br />
as well as each of <str<strong>on</strong>g>the</str<strong>on</strong>g> two ballast density types, 200 Ib/ft^ and 325 Ib/ftl This informati<strong>on</strong><br />
includes:<br />
• Tank name<br />
• Tank volume<br />
• Ballast type density<br />
• Tank weight<br />
Degree Increment:<br />
• Weight<br />
• Percent change<br />
• A KG<br />
• A Trim<br />
A 95% usable volume fracti<strong>on</strong> was utilized for all calculati<strong>on</strong>s. This value provides for<br />
structural internals as well as for any utilities that may be running through <str<strong>on</strong>g>the</str<strong>on</strong>g> spaces. There are<br />
no losses due <str<strong>on</strong>g>to</str<strong>on</strong>g> compacti<strong>on</strong>. According <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> vendor, BTI, because <str<strong>on</strong>g>the</str<strong>on</strong>g> water is removed as <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
material settles, all of <str<strong>on</strong>g>the</str<strong>on</strong>g> voids between particles are filled by water and remain filled by water.<br />
It must be noted again, however, that a settled bed of Perma Ballast® is an extremely effective<br />
barrier against permeati<strong>on</strong> of oxygen - ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bed or through it.<br />
30
2.3 Preliminary Decisi<strong>on</strong>-Making Cost Estimati<strong>on</strong><br />
All decisi<strong>on</strong> making costing or "c<strong>on</strong>cept" estimati<strong>on</strong> was performed by Norfolk Naval<br />
Shipyard's Structural Engineering and Planning Office (Code 256). This preliminary costing<br />
was performed prior <str<strong>on</strong>g>to</str<strong>on</strong>g> any structural analysis. It was presumed that <strong>on</strong>e type of ballast or <strong>on</strong>e<br />
locati<strong>on</strong> of ballast could be ruled out solely based <strong>on</strong> cost al<strong>on</strong>e. As a result, a final cost analysis<br />
would still need <str<strong>on</strong>g>to</str<strong>on</strong>g> be performed after <str<strong>on</strong>g>the</str<strong>on</strong>g> structural analysis was completed. Cost estimati<strong>on</strong><br />
was performed for a combinati<strong>on</strong> of 36 scenarios <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'', 4*, and 8* decks. A specific<br />
number of man-hours were allocated under each shop for jobs associated with <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong> of<br />
Perma Ballast®. These jobs ranged from <str<strong>on</strong>g>the</str<strong>on</strong>g> opening and closing of voids <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> preparing and<br />
painting of any additi<strong>on</strong>al structures. The cost estimati<strong>on</strong> was broken down by man-hours and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n c<strong>on</strong>verted <str<strong>on</strong>g>to</str<strong>on</strong>g> man-days. A <str<strong>on</strong>g>to</str<strong>on</strong>g>tal producti<strong>on</strong> cost was <str<strong>on</strong>g>the</str<strong>on</strong>g>n derived from <str<strong>on</strong>g>the</str<strong>on</strong>g> man-days<br />
required for tank prepping <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast® installati<strong>on</strong>. Similarly, material producti<strong>on</strong> costs<br />
were calculated for prepping a typical void while additi<strong>on</strong>al material costs were additi<strong>on</strong>ally<br />
applied for canning plate installati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"^" deck. A canning plate, used <str<strong>on</strong>g>to</str<strong>on</strong>g> enclose <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
required amount of ballast, would <strong>on</strong>ly be utilized in analysis of <str<strong>on</strong>g>the</str<strong>on</strong>g> 2°^ deck because both <str<strong>on</strong>g>the</str<strong>on</strong>g> 4'<br />
and 8* decks are completely filled in all of <str<strong>on</strong>g>the</str<strong>on</strong>g> modeling scenarios. Any additi<strong>on</strong>al weight added<br />
due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong> of internal structures or stiffening was also tabulated and tracked.<br />
Because <str<strong>on</strong>g>the</str<strong>on</strong>g> 4* and 8* decks did not require canning plates, any costing associated with<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se decks involved limited material costs and fairly minor producti<strong>on</strong> costs. Much of <str<strong>on</strong>g>the</str<strong>on</strong>g> work<br />
associated with all <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks includes:<br />
• Opening and closing of tanks<br />
• Touch-up painting<br />
• Removal and reinstallati<strong>on</strong> of accesses<br />
31
• Testing of all accesses<br />
• Removal and reinstallati<strong>on</strong> of any interferences<br />
• Patching and repair of deck coverings<br />
It was assumed that <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' deck would require structural modificati<strong>on</strong>s due <str<strong>on</strong>g>to</str<strong>on</strong>g> thinner shell<br />
plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> sp<strong>on</strong>s<strong>on</strong>s (compared <str<strong>on</strong>g>to</str<strong>on</strong>g> thicker hull shell plating found <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 8"' deck voids).<br />
Two sp<strong>on</strong>s<strong>on</strong> voids were analyzed in depth for cost estimati<strong>on</strong> purposes, 2-165-8-V and 2-180-6-<br />
V. All producti<strong>on</strong> and material costs were based <strong>on</strong> prepping and work <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> entire tank. As a<br />
result, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'* deck void costs are much higher than <str<strong>on</strong>g>the</str<strong>on</strong>g> 4"* and 8* deck voids due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir size.<br />
Similarly, a thumb rule was applied <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> T"^ deck voids when filled <str<strong>on</strong>g>to</str<strong>on</strong>g> 95% and no canning pate<br />
work was required. The <str<strong>on</strong>g>to</str<strong>on</strong>g>tal structural work, for both producti<strong>on</strong> and material costs, is half <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cost of <str<strong>on</strong>g>the</str<strong>on</strong>g> canning plate work. These cost estimates do not take in<str<strong>on</strong>g>to</str<strong>on</strong>g> account relocati<strong>on</strong> of<br />
existing utilities that may be running through <str<strong>on</strong>g>the</str<strong>on</strong>g> spaces. An analysis was performed, however,<br />
that determined that ballasting <str<strong>on</strong>g>the</str<strong>on</strong>g>se selected tanks would have little, if any impact <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks,<br />
and that relocati<strong>on</strong> of utilities would probably not be required.<br />
Table 2 is an example cost comparis<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> preliminary cost estimati<strong>on</strong> results found.<br />
Producti<strong>on</strong> and material costs are <str<strong>on</strong>g>the</str<strong>on</strong>g> same regardless of <str<strong>on</strong>g>the</str<strong>on</strong>g> density of <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast being used.<br />
Table 2: Deck Locati<strong>on</strong> Cost Comparis<strong>on</strong><br />
2nd Deck 4th Deck 8th Deck<br />
2-165-8-V 2-180-6-V All Voids All Voids<br />
Volume (ft') 3,969 6,273 approx. 600 approx. 1,000<br />
Producti<strong>on</strong> Costs $328,704 $525,958 $21,186 $21,186<br />
Material Costs $22,126 $35,402 $500 $500<br />
Weight Added<br />
a<str<strong>on</strong>g>to</str<strong>on</strong>g>n) 4.71 7.54 0 0<br />
32
All fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r costing calculati<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2°'' deck voids less than 95% filled were <str<strong>on</strong>g>the</str<strong>on</strong>g>n<br />
performed as a percentage of <str<strong>on</strong>g>the</str<strong>on</strong>g> entire tank. For example, if a 2"'' deck sp<strong>on</strong>s<strong>on</strong> void was <str<strong>on</strong>g>to</str<strong>on</strong>g> be<br />
filled 22%, <str<strong>on</strong>g>the</str<strong>on</strong>g>n <str<strong>on</strong>g>the</str<strong>on</strong>g> corresp<strong>on</strong>ding voids producti<strong>on</strong> and material costs were multiplied by 22%.<br />
This was allowable because of <str<strong>on</strong>g>the</str<strong>on</strong>g> nature of <str<strong>on</strong>g>the</str<strong>on</strong>g> geometry of <str<strong>on</strong>g>the</str<strong>on</strong>g> 2°'* deck voids as shown in<br />
Figure 1. Sp<strong>on</strong>s<strong>on</strong> void 2-165-8-V runs 60 feet l<strong>on</strong>g and sp<strong>on</strong>s<strong>on</strong> void 2-180-6-V runs 96 feet<br />
l<strong>on</strong>g. A detailed producti<strong>on</strong> and material cost breakdown for <str<strong>on</strong>g>the</str<strong>on</strong>g> 36 opti<strong>on</strong>s menti<strong>on</strong>ed is located<br />
in Appendix C. The worksheets used <str<strong>on</strong>g>to</str<strong>on</strong>g> perform <str<strong>on</strong>g>the</str<strong>on</strong>g>se cost estimati<strong>on</strong>s are also located in<br />
Appendix C. A complete preliminary cost comparis<strong>on</strong> was <str<strong>on</strong>g>the</str<strong>on</strong>g>n performed for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2° , 4', and<br />
8* decks. This comparis<strong>on</strong> provides <str<strong>on</strong>g>the</str<strong>on</strong>g> following:<br />
• Total Cost<br />
o Producti<strong>on</strong> cost<br />
o Material cost<br />
o<br />
Perma Ballast® cost<br />
• Total Weight (L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns)<br />
o Material Weight<br />
o<br />
Perma Ballast® Weight<br />
• A KG<br />
This decisi<strong>on</strong> making cost comparis<strong>on</strong> revealed that <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density Perma Ballast®<br />
was much more ec<strong>on</strong>omical than <str<strong>on</strong>g>the</str<strong>on</strong>g> 325 Ib/ft^ density Perma Ballast®. It takes nearly <str<strong>on</strong>g>the</str<strong>on</strong>g> same<br />
amount of ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> affect each incremental degree change <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> same deck regardless if using<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ or 325 Ib/ft^. Although <str<strong>on</strong>g>the</str<strong>on</strong>g> number of tanks required <str<strong>on</strong>g>to</str<strong>on</strong>g> ballast with 200 Ib/ft^ was<br />
higher, it was still more cost effective <str<strong>on</strong>g>to</str<strong>on</strong>g> use <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density ballast due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> price per I<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
of <str<strong>on</strong>g>the</str<strong>on</strong>g> 325 Ib/ft^ ballast. The 325 Ib/ft^ ballast has steel shot added <str<strong>on</strong>g>to</str<strong>on</strong>g> it <str<strong>on</strong>g>to</str<strong>on</strong>g> help achieve its high<br />
33
density. It was also discovered at this early stage of analysis that for correcti<strong>on</strong>s at or bey<strong>on</strong>d 1.5<br />
degrees, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2" deck was a much better locati<strong>on</strong> for this ballast additi<strong>on</strong> due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> lesser weight<br />
additi<strong>on</strong> resulting from <str<strong>on</strong>g>the</str<strong>on</strong>g> larger moment arm generated by filling <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' deck voids. The costs<br />
associated with adding ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' deck is much higher, but <str<strong>on</strong>g>the</str<strong>on</strong>g> amount of ballast required<br />
is significantly less than that required for <str<strong>on</strong>g>the</str<strong>on</strong>g> 4"" and 8"' decks. For correcti<strong>on</strong>s less than 1.5<br />
degrees, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2" deck and <str<strong>on</strong>g>the</str<strong>on</strong>g> 8"" decks have a fairly comparable weight additi<strong>on</strong>, however,<br />
ballasting <str<strong>on</strong>g>the</str<strong>on</strong>g> 8' deck tanks costs significantly less. The complete preliminary cost comparis<strong>on</strong><br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"^ 4*^, and 8'" decks is found in Appendix D.<br />
Adding ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' deck voids does increase KG and thus reduces <str<strong>on</strong>g>the</str<strong>on</strong>g> KG service<br />
life allowance margin; however, <str<strong>on</strong>g>the</str<strong>on</strong>g> increase seen is fairly small. In fact, as shown in Appendix<br />
D, a 1.5 degree list correcti<strong>on</strong> results in approximately a 0.1 percent KG increase. On average,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers currently have a KG of 47 feet, as shown in Table 1. The goal KG<br />
service life allowance is not <str<strong>on</strong>g>to</str<strong>on</strong>g> exceed 48.5 feet. Thus, <str<strong>on</strong>g>to</str<strong>on</strong>g> fix an inherent list of 1.5 degrees, <str<strong>on</strong>g>the</str<strong>on</strong>g>re<br />
would be a .05 foot increase in KG.<br />
34
2.4 Structural Analysis<br />
One tank <strong>on</strong> each deck was chosen for structural analysis due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical<br />
similarities between tanks. Analysis was performed <strong>on</strong> any existing shell and/or deck plating, as<br />
well as all l<strong>on</strong>gitudinal and transverse bulkheads for <str<strong>on</strong>g>the</str<strong>on</strong>g> tank chosen from each deck. The<br />
volume of each tank was obtained from POSSE so that <str<strong>on</strong>g>the</str<strong>on</strong>g> weight of Perma Ballast® required <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
fill <str<strong>on</strong>g>the</str<strong>on</strong>g> entire tank could be calculated in I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns. The density used for all <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast®<br />
calculati<strong>on</strong>s was 200 Ib/ft^. All structural calculati<strong>on</strong>s are located in Appendix E.<br />
All surface ships shall be designed <str<strong>on</strong>g>to</str<strong>on</strong>g> withstand a number of loading c<strong>on</strong>diti<strong>on</strong>s including<br />
ship moti<strong>on</strong> loads. Ship moti<strong>on</strong> loads are defined by [6] as <str<strong>on</strong>g>the</str<strong>on</strong>g> inertia forces and gravity<br />
comp<strong>on</strong>ents resulting from <str<strong>on</strong>g>the</str<strong>on</strong>g> moti<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> ship in a seaway. The ship moti<strong>on</strong> fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs for this<br />
analysis were obtained from Naval Sea Systems Command's Ship Survivability Divisi<strong>on</strong>.<br />
Although <str<strong>on</strong>g>the</str<strong>on</strong>g>se fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs will vary slightly depending <strong>on</strong> locati<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g>y were assumed <str<strong>on</strong>g>to</str<strong>on</strong>g> be<br />
c<strong>on</strong>stant. They are as follows:<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.25 Vertical<br />
A := 0.75 Athwartship<br />
F := 0.4 Fore/Aft<br />
Once <str<strong>on</strong>g>the</str<strong>on</strong>g> ship moti<strong>on</strong> fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs were applied <str<strong>on</strong>g>to</str<strong>on</strong>g> each directi<strong>on</strong> respectively, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>tal normal<br />
force could be calculated. The force affecting <str<strong>on</strong>g>the</str<strong>on</strong>g> structural analysis was dependent <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck or bulkhead being analyzed. For example, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>tal force acting <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"<br />
deck's sp<strong>on</strong>s<strong>on</strong> shell plating had <str<strong>on</strong>g>to</str<strong>on</strong>g> be resolved from both a vertical and athwartship force. The<br />
resulting pressure, or equivalent head, <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plating was <str<strong>on</strong>g>the</str<strong>on</strong>g>n found using this resolved normal<br />
force. Each tank was based <strong>on</strong> a 95% usable volume <str<strong>on</strong>g>to</str<strong>on</strong>g> account for structural internals or<br />
utilities running through <str<strong>on</strong>g>the</str<strong>on</strong>g> space.<br />
35
In accordance with [6], panels of plating shall be proporti<strong>on</strong>ed so as not <str<strong>on</strong>g>to</str<strong>on</strong>g> exceed <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
breadth-thickness ratios indicated by:<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
_b ^ C C = coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
t ~ K • -V/H locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
panel<br />
H = head of salt water (feet)<br />
The coefficients C and K are provided in Table I of Secti<strong>on</strong> 100, <str<strong>on</strong>g>the</str<strong>on</strong>g> General<br />
Requirements for Hull Structure, in [6]. There are a number of key assumpti<strong>on</strong>s that were made<br />
following <str<strong>on</strong>g>the</str<strong>on</strong>g>se design criteria for plate panels subjected <str<strong>on</strong>g>to</str<strong>on</strong>g> normal loads. The ship plating is<br />
divided up in<str<strong>on</strong>g>to</str<strong>on</strong>g> any number of panels, depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> amount of stiffening that exists. The<br />
panel is c<strong>on</strong>sidered <str<strong>on</strong>g>to</str<strong>on</strong>g> have clamped or fixed ends and is subject <str<strong>on</strong>g>to</str<strong>on</strong>g> cylindrical bending, a plate<br />
that is subject <str<strong>on</strong>g>to</str<strong>on</strong>g> bending about <strong>on</strong>e axis <strong>on</strong>ly (as usually occurs for l<strong>on</strong>g plates). The cross-<br />
secti<strong>on</strong> of this panel is c<strong>on</strong>sidered <str<strong>on</strong>g>to</str<strong>on</strong>g> be rectangular in shape with a depth equal <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> plating<br />
thickness and a unit width. The K coefficient is important for relatively short panels. The C<br />
coefficient is actually derived from standard beam <str<strong>on</strong>g>the</str<strong>on</strong>g>ory for a fixed-fixed beam, by combining<br />
allowable stress, specific gravity of salt water, and this K coefficient. An example of a C<br />
coefficient derivati<strong>on</strong> starting with beam <str<strong>on</strong>g>the</str<strong>on</strong>g>ory can be seen at <str<strong>on</strong>g>the</str<strong>on</strong>g> end of <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"^* deck sp<strong>on</strong>s<strong>on</strong><br />
shell plating structural calculati<strong>on</strong>s shown in Appendix E.<br />
Also important <str<strong>on</strong>g>to</str<strong>on</strong>g> c<strong>on</strong>sider in <str<strong>on</strong>g>the</str<strong>on</strong>g> structural calculati<strong>on</strong>s, particularly for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'^ deck<br />
sp<strong>on</strong>s<strong>on</strong> shell plating, was <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum shell plating pressure. According <str<strong>on</strong>g>to</str<strong>on</strong>g> CVN 76<br />
specificati<strong>on</strong>s, <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum pressure for sp<strong>on</strong>s<strong>on</strong> shell plating is 1000 psf. As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
limiting weight of Perma Ballast® for <str<strong>on</strong>g>the</str<strong>on</strong>g>se tanks had <str<strong>on</strong>g>to</str<strong>on</strong>g> be calculated based <strong>on</strong> not exceeding<br />
36
this pressure. This resulted in a reducti<strong>on</strong> of approximately 55 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast, for this particular<br />
case <strong>on</strong>ly. Similarly, <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly structural analysis performed for <str<strong>on</strong>g>the</str<strong>on</strong>g> 4* deck void was <strong>on</strong> its deck<br />
plating. Once it was determined that deck stiffening would be required, <str<strong>on</strong>g>the</str<strong>on</strong>g> 4* deck tanks were<br />
taken out of c<strong>on</strong>siderati<strong>on</strong> as a possible locati<strong>on</strong> for placing this ballast. Although adding a<br />
stiffener down <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating would alleviate any structural c<strong>on</strong>cerns, welding <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating would have <str<strong>on</strong>g>to</str<strong>on</strong>g> be performed. With welding required <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m deck plating,<br />
a watch would need <str<strong>on</strong>g>to</str<strong>on</strong>g> be stati<strong>on</strong>ed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r side of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck. The tanks below <str<strong>on</strong>g>the</str<strong>on</strong>g>se 4 deck<br />
tanks are foam filled and a fire watch cannot be stati<strong>on</strong>ed in <str<strong>on</strong>g>the</str<strong>on</strong>g>se tanks.<br />
Once a maximum pressure in head of water was calculated, <str<strong>on</strong>g>the</str<strong>on</strong>g> breadth-thickness ratio<br />
formula could be used again <str<strong>on</strong>g>to</str<strong>on</strong>g> determine <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffener spacing or limiting short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
panel. If <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated maximum distance that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners can be located apart fell less than<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> actual stiffener spacing, <str<strong>on</strong>g>the</str<strong>on</strong>g>n no plastic deformati<strong>on</strong> would occur and stiffening of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating<br />
was not required. If stiffening was required, <str<strong>on</strong>g>the</str<strong>on</strong>g>n <str<strong>on</strong>g>the</str<strong>on</strong>g> panel thickness was usually divided in half<br />
<str<strong>on</strong>g>to</str<strong>on</strong>g> accommodate <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated pressure.<br />
The final calculati<strong>on</strong>s involved verifying that <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated maximum allowable stress<br />
was less than <str<strong>on</strong>g>the</str<strong>on</strong>g> design allowable stress for <str<strong>on</strong>g>the</str<strong>on</strong>g> particular type of steel, regardless of whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
any modificati<strong>on</strong>s were made. The basic equati<strong>on</strong> used <str<strong>on</strong>g>to</str<strong>on</strong>g> calculate <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum stress<br />
governing <str<strong>on</strong>g>the</str<strong>on</strong>g> behavior of plating under lateral load, or plate bending, can be seen below.<br />
Using small deflecti<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g>ory, <str<strong>on</strong>g>the</str<strong>on</strong>g> value of <str<strong>on</strong>g>the</str<strong>on</strong>g> coefficient k depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> boundary<br />
c<strong>on</strong>diti<strong>on</strong>s. For simply supported edges, k=.75 and for clamped edges, k=.5. Simply supported<br />
and clamped structural cases are idealizati<strong>on</strong>s of structural member support illustrating zero<br />
stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On<br />
37
oard ship, structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in<br />
fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. This equati<strong>on</strong> is used for all plates whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r <str<strong>on</strong>g>the</str<strong>on</strong>g>y are<br />
l<strong>on</strong>g or not, and <str<strong>on</strong>g>the</str<strong>on</strong>g> coefficient k also accounts for <str<strong>on</strong>g>the</str<strong>on</strong>g> effect of <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio a/b. Again, b is<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel and t is <str<strong>on</strong>g>the</str<strong>on</strong>g> plating thickness. Figure 1 illustrates graphically <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
stresses in rectangular plates under uniform lateral pressure.<br />
— 050<br />
-^ 0 225<br />
Of<br />
Stress<br />
k P l-j- )<br />
k Depends <strong>on</strong> : piatt edge c<strong>on</strong>diti<strong>on</strong>s<br />
Plote side ratio —<br />
b<br />
Positi<strong>on</strong> of point c<strong>on</strong>sidered<br />
These k values are calculated from<br />
Elastic Small - Deflecti<strong>on</strong> plote <str<strong>on</strong>g>the</str<strong>on</strong>g>ory<br />
j taking Poiss<strong>on</strong>'s rotio i) « 0-3<br />
12 14 1-6 18 2 0<br />
2 2 2 i<br />
Figure 1: Stresses in rectangular plates under uniform lateral pressure [2]<br />
38
2.4.1 Structural Modificati<strong>on</strong>s<br />
2.4.1.1 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2'"' Deck<br />
There were actually three port sp<strong>on</strong>s<strong>on</strong> voids modeled in POSSE <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2° deck.<br />
Due <str<strong>on</strong>g>to</str<strong>on</strong>g> existing geometrical similarities between <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks, <strong>on</strong>ly compartment 2-165-8-V was<br />
analyzed for possible structural modificati<strong>on</strong>s. Basic dimensi<strong>on</strong>s and tank geometry can be seen<br />
below in Figure 2.<br />
FR 175<br />
FR 180<br />
Main Deck<br />
4^<br />
9.83'<br />
6 3/4"<br />
2nd Deck<br />
S Tees, spaced 25" apart {30#)<br />
Figure 2: 2°" Deck Compartment 2-165-8-V<br />
It was found that <strong>on</strong>ly 281 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast could be added <str<strong>on</strong>g>to</str<strong>on</strong>g> this compartment in order<br />
not <str<strong>on</strong>g>to</str<strong>on</strong>g> exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> 1000 psf sp<strong>on</strong>s<strong>on</strong> shell plating maximum pressure criteria. Table 3 shows <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
required structural modificati<strong>on</strong>s for compartment 2-165-8-V for a 281 I<str<strong>on</strong>g>to</str<strong>on</strong>g>n ballast additi<strong>on</strong> at<br />
200 Ib/ft^. All calculati<strong>on</strong>s are located in Appendix E.<br />
39
Table 3: Required Structural Modificati<strong>on</strong>s for 2-165-8-V<br />
Ship Structure<br />
Structural Modiflcati<strong>on</strong>s<br />
Sp<strong>on</strong>s<strong>on</strong> Shell<br />
Plating<br />
Add 7 vertical stiffeners<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 13" X 181.56"<br />
Ship Shell Plating<br />
(Inner L<strong>on</strong>gitudinal<br />
Bulkhead)<br />
No modificati<strong>on</strong>s required<br />
Transverse<br />
Bulkheads (Frames<br />
165,170,175, and<br />
180) No modificati<strong>on</strong>s required<br />
The sp<strong>on</strong>s<strong>on</strong> shell plating required <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong> of 7 vertical stiffeners due <str<strong>on</strong>g>to</str<strong>on</strong>g> its thinner<br />
plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> sp<strong>on</strong>s<strong>on</strong>s. The sp<strong>on</strong>s<strong>on</strong> shell plating is <strong>on</strong>ly 10.2# (.25") plate. The inner<br />
l<strong>on</strong>gitudinal bulkhead, which is really <str<strong>on</strong>g>the</str<strong>on</strong>g> ship shell plating, is 30.6# (.75") and <str<strong>on</strong>g>the</str<strong>on</strong>g> transverse<br />
bulkheads are 20.4# (.5"). Similarly, <str<strong>on</strong>g>the</str<strong>on</strong>g> transverse bulkheads are extensively stiffened, and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
l<strong>on</strong>gitudinal stiffener has <strong>on</strong>e large horiz<strong>on</strong>tal stiffener running down <str<strong>on</strong>g>the</str<strong>on</strong>g> center of <str<strong>on</strong>g>the</str<strong>on</strong>g> bulkhead.<br />
As a result, modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se bulkheads were not required. A cross-secti<strong>on</strong>al view of <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
transverse bulkhead at Frame 165 is shown in Figure 3.<br />
40
Main Deck<br />
Shell<br />
FR 165 - FR 180 Transverse Bulkheads<br />
20.4# (.5")<br />
11.5' ><br />
Stringer #6<br />
Girder<br />
13 7/8" X 6 3/4" Tee-<br />
Ship<br />
Shell<br />
Plating<br />
30.6# (.75")<br />
fr Sp<strong>on</strong>s<strong>on</strong><br />
^Plating<br />
10.2 #(.251<br />
2nd Deck<br />
Stringer #1<br />
Shell<br />
Figure 3: 2 Deck Compartment 2-165-8-V, transverse secti<strong>on</strong><br />
4 th<br />
2.4.1.2 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4" Deck<br />
As menti<strong>on</strong>ed previously, <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly structural analysis performed for <str<strong>on</strong>g>the</str<strong>on</strong>g> 4"^ deck void was<br />
<strong>on</strong> its deck plating. Once it was determined that deck stiffening would be required, <str<strong>on</strong>g>the</str<strong>on</strong>g> 4 deck<br />
tanks were taken out of c<strong>on</strong>siderati<strong>on</strong> as a possible locati<strong>on</strong> for placing this ballast. The 4' deck<br />
voids do not have any stiffened plating. Although adding a stiffener down <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck<br />
plating would alleviate any structural c<strong>on</strong>cerns, welding <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating could not be<br />
performed due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> foam filled void below and <str<strong>on</strong>g>the</str<strong>on</strong>g> inability <str<strong>on</strong>g>to</str<strong>on</strong>g> stati<strong>on</strong> a fire watch <str<strong>on</strong>g>the</str<strong>on</strong>g>re. Table<br />
4, however, shows <str<strong>on</strong>g>the</str<strong>on</strong>g> structural modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating that would be necessary for<br />
ith<br />
41
compartment 4-165-4-V for a 50 I<str<strong>on</strong>g>to</str<strong>on</strong>g>n ballast additi<strong>on</strong> at 200 Ib/ftl All calculati<strong>on</strong>s are located in<br />
Appendix E.<br />
Table 4: Required Structural Modificati<strong>on</strong>s for 4-165-4-V<br />
Ship Structure<br />
Deck Plating<br />
Structural Modificati<strong>on</strong>s<br />
Add 1 l<strong>on</strong>gitudinal stiffener<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 24" X<br />
240"<br />
There were sixteen port voids modeled in POSSE <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4"' deck. Due <str<strong>on</strong>g>to</str<strong>on</strong>g> existing<br />
geometrical similarities between <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks, <strong>on</strong>ly compartment 4-165-4-V was analyzed for<br />
possible structural modificati<strong>on</strong>s. Basic dimensi<strong>on</strong>s and tank geometry can be seen below in<br />
Figure 4.<br />
3rd Deck<br />
FR 170 Transverse Bulkhead<br />
20.4# {.5")<br />
4th Deck Plating<br />
20.4# (.5")<br />
4th Deck<br />
FR 165 Transverse Bulkhead<br />
HB#3 4-4' ^BB#2 20.4# (.5")<br />
40.8#(1.0") 25.5#(.625")<br />
2.4.1.3 Modificati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 8* Deck<br />
There were eleven port voids modeled in POSSE <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> 8* deck. Due <str<strong>on</strong>g>to</str<strong>on</strong>g> existing<br />
geometrical similarities between <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks, <strong>on</strong>ly compartment 8-225-6-V was analyzed for<br />
possible structural modificati<strong>on</strong>s. Basic dimensi<strong>on</strong>s and tank geometry can be seen below in<br />
Figure 5.<br />
Innsr L<strong>on</strong>gitudinal Bulkhead<br />
(Shaft Alley Bulkhead #4)<br />
14.024# (.343")<br />
Outer L<strong>on</strong>gitudinal Bulkhead<br />
(L<strong>on</strong>gitudinal Bulkhead #3)<br />
17.85# (.437')<br />
FR 230 Trans^/erse Bulkhead<br />
12:75# (.3125")<br />
Shell Plating<br />
30.S# (.75")<br />
FR 225 Transverse Bulkhead<br />
'Q.- ^-1. 15.3#(.375l<br />
, —Stringer #14<br />
^Stringer #11<br />
Figure 5: 8* Deck Compartment 8-225-6-V<br />
There is c<strong>on</strong>siderable stiffening already in all <str<strong>on</strong>g>the</str<strong>on</strong>g> 8* deck voids. It was determined,<br />
however, that <str<strong>on</strong>g>the</str<strong>on</strong>g> plating thickness for <str<strong>on</strong>g>the</str<strong>on</strong>g>se voids is much thinner than initially estimated. As a<br />
result, most of <str<strong>on</strong>g>the</str<strong>on</strong>g> bulkheads require stiffening. Structural analysis was first performed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
shell plating. A minimum ballast weight of 227 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns was calculated so that structural<br />
modificati<strong>on</strong>s would not be required <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship shell plating. This weight, however, is still <str<strong>on</strong>g>to</str<strong>on</strong>g>o<br />
high for <str<strong>on</strong>g>the</str<strong>on</strong>g> rest of <str<strong>on</strong>g>the</str<strong>on</strong>g> bulkheads, as <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r bulkheads do require stiffening. It is<br />
recommended that a stiffener be placed between each existing stiffener <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>gitudinal and<br />
transverse bulkheads. Table 5 shows <str<strong>on</strong>g>the</str<strong>on</strong>g> required structural modificati<strong>on</strong>s for compartment 8-<br />
225-6-V for a 227 I<str<strong>on</strong>g>to</str<strong>on</strong>g>n ballast additi<strong>on</strong> at 200 Ib/ft^. All calculati<strong>on</strong>s are located in Appendix E.<br />
43
Table 5: Required Structural Modificati<strong>on</strong>s for 8-225-6-V<br />
Ship Structure<br />
Structural Modiflcati<strong>on</strong>s<br />
Shell Plating<br />
Inner L<strong>on</strong>gitudinal<br />
Bulkhead (Shaft Alley<br />
Bulkhead #4)<br />
Outer L<strong>on</strong>gitudinal<br />
Bulkhead (Bulkhead<br />
#3)<br />
Transverse Bulkhead<br />
(Frame 225)<br />
Transverse Bulkhead<br />
(Frame 230)<br />
No modificati<strong>on</strong>s required<br />
Add 5 vertical stiffeners<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 24" X 114"<br />
Add 5 vertical stiffeners<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 24" X 87"<br />
Add 4 vertical stiffeners<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 15" X 114"<br />
*Note-panel height is dependent <strong>on</strong><br />
trapezoidal geometry<br />
Add 4 vertical stiffeners<br />
(5" X 4" X 7.5# X T) (MS)<br />
Max Panel Plating Size: 15" X 114"<br />
*Note-panel height is dependent <strong>on</strong><br />
trapezoidal geometry<br />
3.0 Final Analysis and Results<br />
This project design spiraled <str<strong>on</strong>g>to</str<strong>on</strong>g>ward finding <str<strong>on</strong>g>the</str<strong>on</strong>g> most cost effective and advantageous<br />
solid ballasting soluti<strong>on</strong> for correcting <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers. The<br />
preliminary decisi<strong>on</strong>-making cost estimati<strong>on</strong> proved that <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density was <str<strong>on</strong>g>the</str<strong>on</strong>g> most cost<br />
effective for <str<strong>on</strong>g>the</str<strong>on</strong>g> same amount of ballast weight. The 325 Ib/ft^ ballast was so much more<br />
expensive, that although <str<strong>on</strong>g>the</str<strong>on</strong>g> number of tanks required <str<strong>on</strong>g>to</str<strong>on</strong>g> ballast with 200 Ib/ft^ was higher, it was<br />
still more cost effective <str<strong>on</strong>g>to</str<strong>on</strong>g> use <str<strong>on</strong>g>the</str<strong>on</strong>g> 200 Ib/ft^ density ballast. Once <str<strong>on</strong>g>the</str<strong>on</strong>g> structural analysis was<br />
complete, <str<strong>on</strong>g>the</str<strong>on</strong>g> minimum ballasting weights that were found had <str<strong>on</strong>g>to</str<strong>on</strong>g> be analyzed in POSSE again.<br />
For this analysis, <str<strong>on</strong>g>the</str<strong>on</strong>g> 4'*' deck was eliminated completely due <str<strong>on</strong>g>to</str<strong>on</strong>g> its structural limitati<strong>on</strong>s.<br />
Similarly, any required structural modificati<strong>on</strong>s that were not already included in <str<strong>on</strong>g>the</str<strong>on</strong>g> cost<br />
estimati<strong>on</strong>s had <str<strong>on</strong>g>to</str<strong>on</strong>g> be taken in <str<strong>on</strong>g>to</str<strong>on</strong>g> account for both <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' and S"' decks.<br />
44
3.1 Final POSSE Results<br />
The minimum amount of 200 Ib/ft^ ballast that could be added <str<strong>on</strong>g>to</str<strong>on</strong>g> compartment 2-165-8-V<br />
was found <str<strong>on</strong>g>to</str<strong>on</strong>g> be 281 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns which corresp<strong>on</strong>ds <str<strong>on</strong>g>to</str<strong>on</strong>g> 79% of that compartment's <str<strong>on</strong>g>to</str<strong>on</strong>g>tal capacity. Up<br />
until this point, all tanks had been analyzed <str<strong>on</strong>g>to</str<strong>on</strong>g> 95% of <str<strong>on</strong>g>to</str<strong>on</strong>g>tal capacity due <str<strong>on</strong>g>to</str<strong>on</strong>g> structural internals or<br />
possible utilities running through <str<strong>on</strong>g>the</str<strong>on</strong>g> space. Structural analysis was <str<strong>on</strong>g>the</str<strong>on</strong>g>n performed for<br />
compartment 2-180-6-V. A minimum ballast weight of 448 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns was calculated so that <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
maximum pressure design criteri<strong>on</strong> of 1000 psf was not violated. Because less ballast could be<br />
added <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se tanks, <str<strong>on</strong>g>the</str<strong>on</strong>g> POSSE analysis had <str<strong>on</strong>g>to</str<strong>on</strong>g> be expanded <str<strong>on</strong>g>to</str<strong>on</strong>g> include compartment 2-250-4-V.<br />
These new results for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2""^ deck had little effect <strong>on</strong> KG and <strong>on</strong>ly enhanced <str<strong>on</strong>g>the</str<strong>on</strong>g> aft trim<br />
correcti<strong>on</strong>.<br />
The minimum amount of 200 Ib/ft^ ballast that could be added <str<strong>on</strong>g>to</str<strong>on</strong>g> compartment 8-225-6-V<br />
was 227 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns. This was calculated <str<strong>on</strong>g>to</str<strong>on</strong>g> avoid performing structural modificati<strong>on</strong>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship shell<br />
plating. As a result, <strong>on</strong>ly 90% of that compartment's <str<strong>on</strong>g>to</str<strong>on</strong>g>tal capacity could be utilized which was<br />
5% less than originally analyzed in POSSE. This time, ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r than perform a structural analysis<br />
<strong>on</strong> all <str<strong>on</strong>g>the</str<strong>on</strong>g> 8* deck voids, a maximum capacity thumb rule of 90% was applied <str<strong>on</strong>g>to</str<strong>on</strong>g> all <str<strong>on</strong>g>the</str<strong>on</strong>g> 8"' deck<br />
voids. As a result, different tanks were selected and analyzed <str<strong>on</strong>g>to</str<strong>on</strong>g> achieve <str<strong>on</strong>g>the</str<strong>on</strong>g> least I<str<strong>on</strong>g>to</str<strong>on</strong>g>n additi<strong>on</strong><br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> same incremental change in degrees. Again, this had little effect <strong>on</strong> KG and change in<br />
trim.<br />
A table providing POSSE modeling results in a combat load c<strong>on</strong>diti<strong>on</strong> for list correcti<strong>on</strong><br />
in half degree increments up <str<strong>on</strong>g>to</str<strong>on</strong>g> 3 degrees for 200 Ib/ft^ is included in Appendix F. This<br />
informati<strong>on</strong> includes:<br />
• Tank name<br />
• Tank volume<br />
45
• Ballast type density<br />
• Tank weight<br />
Degree Increment:<br />
• Weight<br />
• Percent change<br />
• A KG<br />
• A Trim<br />
3.2 Final Cost Estimati<strong>on</strong><br />
Once <str<strong>on</strong>g>the</str<strong>on</strong>g> POSSE modeling analysis was complete, a final cost assessment was made<br />
based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> new results for list correcti<strong>on</strong> in half degree increments up <str<strong>on</strong>g>to</str<strong>on</strong>g> 3 degrees for <str<strong>on</strong>g>the</str<strong>on</strong>g> T^<br />
and 8"" deck tanks. Because <str<strong>on</strong>g>the</str<strong>on</strong>g> 8'*' deck tanks now had <str<strong>on</strong>g>to</str<strong>on</strong>g> be stiffened, <str<strong>on</strong>g>the</str<strong>on</strong>g> material costs and<br />
material weights had <str<strong>on</strong>g>to</str<strong>on</strong>g> be determined. The producti<strong>on</strong> costs were assumed <str<strong>on</strong>g>to</str<strong>on</strong>g> be <str<strong>on</strong>g>the</str<strong>on</strong>g> same. This<br />
informati<strong>on</strong> is included in Appendix G. Also, analysis <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> T^ deck revealed that<br />
compartment 2-250-2-V had <str<strong>on</strong>g>to</str<strong>on</strong>g> be used when trying <str<strong>on</strong>g>to</str<strong>on</strong>g> correct 3 degrees of list. Code 256<br />
provided producti<strong>on</strong> and material costs as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> material weights for tank prepping <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Perma Ballast® installati<strong>on</strong>.<br />
All cost estimati<strong>on</strong>s were calculated and derived as previously discussed in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
preliminary cost estimati<strong>on</strong> secti<strong>on</strong>. This time, however, 2"^* deck tanks were based <strong>on</strong><br />
approximately 80% fillable capacity and S"" deck tanks were based <strong>on</strong> approximately 90%<br />
finable capacity. When filled <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se capacities, canning plate work was not required.<br />
Similarly, any additi<strong>on</strong>al weight added due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong> of internal structures or stiffening was<br />
again tabulated and tracked. Table 6 shows <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>tal cost, <str<strong>on</strong>g>to</str<strong>on</strong>g>tal weight additi<strong>on</strong>, and change in<br />
KG for each half degree increment <strong>on</strong> both <str<strong>on</strong>g>the</str<strong>on</strong>g> T^ and 8'*' decks.<br />
46
Table 6: Final Cost, Weight Additi<strong>on</strong>, and Change in KG Comparis<strong>on</strong><br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> (Degrees) 0.5 1 1.5<br />
Ballast Density (200 lbs/ft') (200 lbs/ft^) (200 lbs/ft^)<br />
Tank Locati<strong>on</strong><br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
Producti<strong>on</strong> Cost ($) 115,046 42,372 243,240 84,744 280,062 127,116<br />
Material Cost ($) 7,744 8,850 16,373 17,700 18,851 26,550<br />
Perma Cost ($)** 127,900 139,825 158,950 186,400 190,675 227,125<br />
Total Cost ($) 250,690 191,047 418,563 288,844 489,588 380,791<br />
Material Weight<br />
(L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 1.65 0.80 3.49 1.61 4.01 2.41<br />
Perma Weight (L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 124 177 262 384 403 565<br />
Total Weight (L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 125.65 177.80 265.49 385.61 407.01 567.41<br />
A KG (ft)** +0.02 -0.02 +0.04 -0.05 +0.05 -0.08<br />
**Perma cost estimates 5ased<strong>on</strong> $1 00,000 + $: >25/lt for 200 lbs/ft'^3<br />
**(+) indicates increasing KG which is a negative effect<br />
**(-) indicates decreasing KG which is a positive effect<br />
<str<strong>on</strong>g>List</str<strong>on</strong>g> (Degrees) 2 2.5 3<br />
Ballast Density (20011 bs/ft^) (20011 t>s/ft') (2001 bs/ft^)<br />
Tank Locati<strong>on</strong><br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
2nd<br />
Deck<br />
8th<br />
Deck<br />
Producti<strong>on</strong> Cost ($) 411,552 148,302 427,331 211,860 478,840 233,046<br />
Material Cost ($) 27,701 30,975 28,764 44,250 32,231 48,675<br />
Perma Cost ($)** 222,175 295,075 253,675 341,200 288,775 392,050<br />
Total Cost ($) 661,428 474,352 709,770 597,310 799,846 673,771<br />
Material Weight<br />
(L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 5.90 2.81 6.13 4.02 6.86 4.42<br />
Perma Weight (L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 543 867 683 1,072 839 1,298<br />
Total Weight (L<str<strong>on</strong>g>to</str<strong>on</strong>g>ns) 548.90 869.81 689.13 1,076.02 845.86 1302.42<br />
A KG (ft)** +0.07 -0.13 +0.09 -0.14 +0.11 -0.17<br />
**Perma cost estimates jased <strong>on</strong> $1 00,000 + $: I25l\i for 20 0 lbs/ft'^3<br />
**(+) indicates increasing KG which is a negative effect<br />
**(-) indicates decreasing KG which is a positive effect<br />
47
3.2.1 Ease of Removal<br />
As menti<strong>on</strong>ed previously, Perma Ballast® is removable. In fact, removal costs were ^<br />
assessed as well for this project <strong>on</strong> a per tank basis. For <str<strong>on</strong>g>the</str<strong>on</strong>g> purposes of this <str<strong>on</strong>g>the</str<strong>on</strong>g>sis, all tank<br />
prepping costs for ballast removal by BTI were also calculated by Norfolk Naval Shipyard (Code<br />
256). It was estimated that it would cost approximately $78,652 for labor and material <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
remove/reinstall accesses and interferences for <strong>on</strong>e 8"" deck tank, and approximately $63,412 for<br />
labor and material <str<strong>on</strong>g>to</str<strong>on</strong>g> remove/reinstall accesses for <strong>on</strong>e 2"^* deck tank.<br />
Ballast removal costs were also obtained from BTI. It was determined that it would be<br />
best for BTI <str<strong>on</strong>g>to</str<strong>on</strong>g> actually remove <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast and dispose of it due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> high costs involved should<br />
a naval shipyard need <str<strong>on</strong>g>to</str<strong>on</strong>g> dispose of <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast. For ballast removal, BTI will charge a fixed fee •<br />
of $100,000 for locating and utilizing <str<strong>on</strong>g>the</str<strong>on</strong>g>ir equipment and approximately $395 <str<strong>on</strong>g>to</str<strong>on</strong>g> remove <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ballast per I<str<strong>on</strong>g>to</str<strong>on</strong>g>n. They also estimated approximately $65 per I<str<strong>on</strong>g>to</str<strong>on</strong>g>n <str<strong>on</strong>g>to</str<strong>on</strong>g> dispose of it. All pricing is<br />
based <strong>on</strong> disposal of 100% of <str<strong>on</strong>g>the</str<strong>on</strong>g> water used <str<strong>on</strong>g>to</str<strong>on</strong>g> re-slurry <str<strong>on</strong>g>the</str<strong>on</strong>g> material.<br />
I*<br />
For example, a 1.5 degree list correcti<strong>on</strong> would require approximately 400 I<str<strong>on</strong>g>to</str<strong>on</strong>g>n of ballast<br />
and would need <str<strong>on</strong>g>to</str<strong>on</strong>g> be removed from two 2"*^ deck tanks. This would result in a <str<strong>on</strong>g>to</str<strong>on</strong>g>tal removal ^<br />
cost of $347,412 of which $284,000 is for <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast removal and $63,412 is for removing and<br />
reinstalling accesses. It should be noted that this ballast additi<strong>on</strong> is <strong>on</strong>ly as permanent a soluti<strong>on</strong><br />
as it needs <str<strong>on</strong>g>to</str<strong>on</strong>g> be. For example, should future modificati<strong>on</strong>s entail replacing <str<strong>on</strong>g>the</str<strong>on</strong>g> old <strong>Nimitz</strong> island ^<br />
with a new CVN 76 island, it would <str<strong>on</strong>g>the</str<strong>on</strong>g>n be desirable and cost effective <str<strong>on</strong>g>to</str<strong>on</strong>g> remove this ballast.<br />
3.2.2 Evidence Perma Ballast® is n<strong>on</strong>-corrosive<br />
Recently, <str<strong>on</strong>g>the</str<strong>on</strong>g> American Bureau of Shipping (ABS) required a sealift c<strong>on</strong>versi<strong>on</strong> vessel<br />
that installed this Perma Ballast® in 1984 <str<strong>on</strong>g>to</str<strong>on</strong>g> remove its ballast. C<strong>on</strong>cern had arisen because a<br />
tank inspecti<strong>on</strong> revealed that corrosi<strong>on</strong> coup<strong>on</strong>s had underg<strong>on</strong>e significant weight loss. ti<br />
48
Corrosi<strong>on</strong> coup<strong>on</strong>s are placed in all tanks that have Perma Ballast® installed so that periodic<br />
tank inspecti<strong>on</strong>s can be made <str<strong>on</strong>g>to</str<strong>on</strong>g> determine if corrosi<strong>on</strong> exists. It turned out that <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong><br />
coup<strong>on</strong>s were improperly attached <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> manhole covers and <strong>on</strong>ly rested in <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>to</str<strong>on</strong>g>ps of <str<strong>on</strong>g>the</str<strong>on</strong>g> beds<br />
of Perma Ballast®. The corrosi<strong>on</strong> coup<strong>on</strong>s should be hung <strong>on</strong> chains and buried within <str<strong>on</strong>g>the</str<strong>on</strong>g> bed<br />
of ballast. Over <str<strong>on</strong>g>the</str<strong>on</strong>g> years, <str<strong>on</strong>g>the</str<strong>on</strong>g> coup<strong>on</strong>s were repeatedly exposed <str<strong>on</strong>g>to</str<strong>on</strong>g> air and water during<br />
inspecti<strong>on</strong>s, ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r than being properly re-installed in<str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast®. ABS did report,<br />
however, that all 4 of <str<strong>on</strong>g>the</str<strong>on</strong>g> tanks were in perfect c<strong>on</strong>diti<strong>on</strong> after <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma Ballast® removal,<br />
almost 20 years after initial installati<strong>on</strong>. Actual cost data was also obtained from this vessel.<br />
The cost <str<strong>on</strong>g>to</str<strong>on</strong>g> cut in<str<strong>on</strong>g>to</str<strong>on</strong>g> 8 compartments and remove <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast was approximately $250,000. The<br />
cost <str<strong>on</strong>g>to</str<strong>on</strong>g> replace <str<strong>on</strong>g>the</str<strong>on</strong>g> steel and reweld <str<strong>on</strong>g>the</str<strong>on</strong>g> hull after <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast was reinstalled was approximately<br />
$100,000. As <strong>on</strong>e can see, <str<strong>on</strong>g>the</str<strong>on</strong>g> removal costs are relatively low and experience proves that<br />
corrosi<strong>on</strong> will not be a c<strong>on</strong>cern.<br />
49
4.0 C<strong>on</strong>clusi<strong>on</strong><br />
Solid ballast is <str<strong>on</strong>g>the</str<strong>on</strong>g> most advantageous soluti<strong>on</strong> for correcting <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<strong>Nimitz</strong> class aircraft carriers. Table 6 illustrates that <str<strong>on</strong>g>the</str<strong>on</strong>g>re are a number of advantages and<br />
disadvantages that must be c<strong>on</strong>sidered when determining <str<strong>on</strong>g>the</str<strong>on</strong>g> proper locati<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> Perma<br />
Ballast®.<br />
• The 2" deck is <str<strong>on</strong>g>the</str<strong>on</strong>g> choice locati<strong>on</strong> for list correcti<strong>on</strong>s at or bey<strong>on</strong>d 1.5 degrees.<br />
The costs associated with adding ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"^^ deck is much higher, but <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
amount of ballast required is significantly less than that required for <str<strong>on</strong>g>the</str<strong>on</strong>g> 4'^ and 8<br />
decks.<br />
o Advantages:<br />
■ significantly less weight added<br />
o Disadvantages:<br />
■ more costly<br />
■ increased KG*<br />
• For list correcti<strong>on</strong>s less than 1.5 degrees, <str<strong>on</strong>g>the</str<strong>on</strong>g> choice locati<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g> S'*' deck. Less<br />
than 1.5 degrees, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2"'' and 8"" decks have a fairly comparable weight additi<strong>on</strong>,<br />
however, ballasting <str<strong>on</strong>g>the</str<strong>on</strong>g> 8'*' deck tanks costs significantly less.<br />
o Advantages:<br />
■ significantly less costly<br />
■ decreased KG*<br />
o Disadvantages:<br />
■ increased weight additi<strong>on</strong><br />
th<br />
*Any positive change in KG serves <str<strong>on</strong>g>to</str<strong>on</strong>g> reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> remaining KG service life allowance. The<br />
average KG service life allowance remaining for most carriers is approximately 1.5 feet. Even<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> greatest list correcti<strong>on</strong> of 3 degrees is <strong>on</strong>ly a 7% reducti<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g> remaining KG service life<br />
allowance for <str<strong>on</strong>g>the</str<strong>on</strong>g> aircraft carriers.<br />
50
5.0 Recommendati<strong>on</strong>s<br />
1. As can be seen in Table 1, most of <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class aircraft carriers currently have an<br />
average list of approximately 1.5 degrees. It is recommended that <str<strong>on</strong>g>the</str<strong>on</strong>g> ships be ballasted <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
T^ deck at this point <str<strong>on</strong>g>to</str<strong>on</strong>g> avoid adding excess ballast as menti<strong>on</strong>ed previously. The cost is<br />
approximately 22% higher, but <str<strong>on</strong>g>the</str<strong>on</strong>g> weight additi<strong>on</strong> is approximately 28% less. This is a<br />
c<strong>on</strong>siderable amount of weight reducti<strong>on</strong>. The displacement service life allowance must also be<br />
analyzed. If you assume a c<strong>on</strong>tract displacement of 100,000 l<strong>on</strong>g <str<strong>on</strong>g>to</str<strong>on</strong>g>ns with a 5% service life<br />
displacement allowance for an in-service carrier, <str<strong>on</strong>g>the</str<strong>on</strong>g>n 400 l<strong>on</strong>g <str<strong>on</strong>g>to</str<strong>on</strong>g>ns <str<strong>on</strong>g>to</str<strong>on</strong>g> correct 1.5 degrees of<br />
inherent list would be less than 1/10 of <str<strong>on</strong>g>the</str<strong>on</strong>g> service life (100,000 * .05 = 5,000 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns and 400 /<br />
5000 is approx. 8%). This can be viewed as a significant change in displacement or a relatively<br />
small change in displacement when looking at all <str<strong>on</strong>g>the</str<strong>on</strong>g> advantages that come with correcting <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
inherent list <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>Nimitz</strong> class carriers. Also, <str<strong>on</strong>g>the</str<strong>on</strong>g> cost per I<str<strong>on</strong>g>to</str<strong>on</strong>g>n for a 1.5 degree list correcti<strong>on</strong> is<br />
approximately $1,200. This is truly inexpensive from a survivability standpoint and also reduces<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> operati<strong>on</strong>al c<strong>on</strong>straints placed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship.<br />
2. The prudent manner in which <str<strong>on</strong>g>to</str<strong>on</strong>g> handle <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list associated with each aircraft<br />
carrier is <str<strong>on</strong>g>to</str<strong>on</strong>g> perform an inclining experiment <strong>on</strong> each carrier. The inclining experiment data can<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n be used <str<strong>on</strong>g>to</str<strong>on</strong>g> assess <str<strong>on</strong>g>the</str<strong>on</strong>g> amount of ballast necessary for installati<strong>on</strong> and can be c<strong>on</strong>ducted when<br />
each ship's operati<strong>on</strong>al schedule will permit it. As menti<strong>on</strong>ed previously, much of <str<strong>on</strong>g>the</str<strong>on</strong>g> data for<br />
each carrier has been extrapolated from re-evaluati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> results of <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 71 Displacement<br />
Test and <str<strong>on</strong>g>the</str<strong>on</strong>g> CVN 68 Post-RCOH inclining experiment. Knowing that <str<strong>on</strong>g>the</str<strong>on</strong>g>se tests are extremely<br />
expensive and that CVN 71-75 are <str<strong>on</strong>g>the</str<strong>on</strong>g> carriers in need of list correcti<strong>on</strong>, perhaps an inclining<br />
experiment could be performed <strong>on</strong> <strong>on</strong>e of <str<strong>on</strong>g>the</str<strong>on</strong>g>se carriers so that data could <str<strong>on</strong>g>the</str<strong>on</strong>g>n be extrapolated<br />
fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r.<br />
51
3. Until this point, <str<strong>on</strong>g>the</str<strong>on</strong>g>re has been Httle menti<strong>on</strong> of what reducing <str<strong>on</strong>g>the</str<strong>on</strong>g> inherent list could<br />
do for manpower reducti<strong>on</strong>. The number of man-hours that could be saved due <str<strong>on</strong>g>to</str<strong>on</strong>g> fixing this<br />
problem could far outweigh anything discussed in this project so far. This is certainly something<br />
that should be studied and investigated as well.<br />
^<br />
52
References<br />
[I] Design Data Sheet 079-1, "Stability and buoyancy of U. S. Naval Surface Ships,"<br />
Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Naval Ship Engineering Center.<br />
[2] Hughes, Owen F., "Ship Structural Design: A Rati<strong>on</strong>ally-Based, Computer-Aided<br />
Optimizati<strong>on</strong> Approach," The Society of Naval Architects and Marine Engineers, 1988.<br />
[3] NAVSEA 0900-LP-097-4010, "Structural Design Manual For Naval Surface Ships,"<br />
Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Naval Sea System Command, 15 December 1976.<br />
[4] NAVSEAINST 9096.3D, "Weight and Moment Compensati<strong>on</strong> and Limiting Drafts for<br />
Naval Surface Ships," Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Naval Sea Systems Command, 16<br />
August 2001.<br />
[5] NAVSEAINST 9096.6B, "Policy for Weight and Vertical Center of Gravity Above<br />
Bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m of Keel (KG) Margins for Surface Ships," Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Naval Sea<br />
Systems Command, 16 August 2001.<br />
[6] NAVSEA S9AA0-AA-SPN-010, "General Specificati<strong>on</strong> for Ships of <str<strong>on</strong>g>the</str<strong>on</strong>g> United States<br />
Navy," Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Naval Sea Systems Command, 1991.<br />
[7] <strong>Nimitz</strong> <strong>Class</strong> Ship Specificati<strong>on</strong>s<br />
[8] <strong>Nimitz</strong> <strong>Class</strong> Ship Characteristics and Drawings<br />
[9] N.S. NAPPI ASSOCIATES, INC, "Investigati<strong>on</strong> of an Alternative Method for<br />
Determining <str<strong>on</strong>g>the</str<strong>on</strong>g> Limiting Displacement for Strength for CVN 68-CVN 70 Ships,"<br />
Rockville, Maryland, January 2003.<br />
[10] OPNAVINST 9070.1, "Survivability Policy for Surface Ships of <str<strong>on</strong>g>the</str<strong>on</strong>g> U. S. Navy,"<br />
Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Office of <str<strong>on</strong>g>the</str<strong>on</strong>g> Chief of Naval Operati<strong>on</strong>s, 23 September 1988.<br />
[II] OPNAVINST 9096.1, "Weight and Stability Limits for Naval Surface Ships,"<br />
Department of <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy, Office of <str<strong>on</strong>g>the</str<strong>on</strong>g> Chief of Naval Operati<strong>on</strong>s, 12 November 1985.<br />
[12] Mal<strong>on</strong>e, Michael L., "An Alternate Method for <str<strong>on</strong>g>the</str<strong>on</strong>g> Determinati<strong>on</strong> of <strong>Aircraft</strong> <strong>Carriers</strong><br />
Limiting Displacement for Strength," Master's Thesis, Massachusetts Institute of<br />
Technology, June 2001.<br />
[13] Roark, Raym<strong>on</strong>d J., "Formulas for Stress and Strain," McGraw-Hill Book Company,<br />
1975.<br />
[14] USS Dwight D. Eisenhower (CVN 69) Engineering Department Standing Order 05, "<str<strong>on</strong>g>List</str<strong>on</strong>g><br />
C<strong>on</strong>trol System Management," Engineering Department, USS Dwight D. Eisenhower<br />
(CVN 69), 30 December 1999.<br />
53
Appendix A: Tank Locati<strong>on</strong> Study<br />
54
O<br />
CO<br />
■*.<br />
CM<br />
d CVI<br />
d CVI<br />
d CO<br />
d CO<br />
d CO<br />
d CO<br />
d CVI<br />
d CVI<br />
d CVI<br />
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Appendix B: Preliminary POSSE Modeling Results<br />
Provided by Norfolk Naval Shipyard Structural Engineering and Planning Office (Code 256)<br />
58
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62
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MATERIAL WORK SHEET<br />
PERMA BALLAST® INSTALLATION<br />
SHOP PC# MATERIAL STOCK NO. QTY SS/PUR COST<br />
CANNING PLATES:<br />
600 SF AREA FOR 2-165-8-V<br />
AT 100% COVERAGE<br />
llSl 001 10.2# OSS PLATE (10.2#/SF) 9515-00-153-3184 600 $4.12/SF $2,472<br />
llSl 002 2-1/2 X 2-1/2" ANGLE (4.1#LF) 9520-00-277-4920 170 $2.12/FT $360<br />
SPONSON STIFFENING:<br />
llSl 003 5" X 4" ANGLE (7.5#LF) 9520-00-277-5978 225 $6.46/FT $1,454<br />
71AA 004 PAINT $1,200<br />
74YY N/A BLAST AND PAINT FACILITY $12,000<br />
ALL N/A CONSUMABLES $4,640<br />
TOTAL MATERIAL COSTS: $22,126<br />
TOTAL MATERIAL WEIGHT:<br />
10,556 #'S<br />
64
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PERAAA BALLAST® INSTALLATION<br />
SHOP PC# MATERIAL STOCK NO. Qjy SS/PUR COST<br />
CANNING PLATES:<br />
960 SF AREA FOR 2-180-6-V<br />
AT 100% COVERAGE<br />
llSl 001 10.2# OSS PLATE (10.2#/SF) 9515-00-153-3184 960 $4.12/SF $3,955<br />
llSl 002 2-1/2 X 2-1/2" ANGLE (4.1#LF) 9520-00-277-4920 275 $2.12/FT $583<br />
SPONSON STIFFENING:<br />
llSl 003 5" X 4" ANGLE (7.5#LF) 9520-00-277-5978 360 $6.46/FT $2,326<br />
71AA 004 PAINT $1,920<br />
74YY N/A BLAST AND PAINT FACILITY $19,200<br />
ALL N/A CONSUMABLES $7,418<br />
TOTAL MATERIAL COSTS: $35,402<br />
TOTAL MATERIAL WEIGHT:<br />
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86
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Appendix E: Complete Structural Analysis
structural Analysis for Compartment 2-165-8-V; Shell Plating<br />
Perma Ballast® Data<br />
PP: erma :=200A<br />
ft^<br />
/"Perma fill :=.9f<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
lb<br />
Psw:=64.4—<br />
ft<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Seawater<br />
Compartment 2-165-8-V<br />
Volume := 3969ft^<br />
Volume of Compartment<br />
^Perma •" 354<str<strong>on</strong>g>to</str<strong>on</strong>g>n Weight of Permanent Ballast<br />
FR 175<br />
FR180<br />
Main Deck<br />
9.83*<br />
2nd Deck<br />
6 Tees, spaced 26" apart {7.6#)<br />
89
Main Deck<br />
FR 165 - FR 180 Transverse Bulkheads<br />
20.4# (.5")<br />
11.5* ><br />
Stringer #6<br />
Girder<br />
Ship<br />
Shell<br />
Plating<br />
30.6# (.75<br />
10.2 # (.25")<br />
2nd Deck<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
Shell<br />
V := 1.2f Vertical a := asinf^^<br />
V1513<br />
A := 0.7f Athwartship p<br />
. (^9.83<br />
:= asm •<br />
V 15.13<br />
F := 0.4 Fore/Aft<br />
a = 49.47 Ideg<br />
P =40.519deg<br />
Loading <strong>on</strong> Shell Plating:<br />
Wperma = 7.93x10^ lb<br />
Weight of Perma Ballast®<br />
Fv:=V-Wp,^,<br />
Fy = 9.912X 10 lb Vertical Load (Downward)<br />
F^ := A • Wpg^3<br />
F^ = 5.947X 10 lb Athwartship Load (Port)<br />
Fp :- F • Wpgj.j„3<br />
Fp = 3.172X 10 lb Fore/Aft Load<br />
% := Fy ■ '=os(P) + FA ' cos(a) F^ = 1.14x 10^lb Normal Force<br />
90
Resulting Pressure <strong>on</strong> Sp<strong>on</strong>s<strong>on</strong> Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 60ft Ht := 15.13ft<br />
Area := L ■ Ht<br />
Area = 907.8ft^<br />
P:=<br />
^N<br />
Area<br />
.3 lb<br />
P = 1.256X 10"<br />
ft<br />
P = 8.72—<br />
. 2<br />
m<br />
.3 lb_<br />
^95% '■= %erma_fill' ^ ^95% = ^"^^^^ ^^ —<br />
.2<br />
^^^^^ °" ^^^^ F^"^^^® Volume<br />
ft<br />
H:= ^95%<br />
sw<br />
H = 18.524ft<br />
Equivalent Head<br />
In accordance with CVN 76 Specs, sp<strong>on</strong>s<strong>on</strong> plating aft of Frame 88 shall be designed for 1000 psf. Therefore, less ballast must<br />
be added <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se sp<strong>on</strong>s<strong>on</strong> voids.<br />
1193 psf> 1000 psf<br />
91
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
Panels of plating shall be proporti<strong>on</strong>ed so as not <str<strong>on</strong>g>to</str<strong>on</strong>g> exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> breadth-thickness ratios<br />
found below:<br />
b := 2fin a := 240in AR := — AR = 0.108<br />
a<br />
^actual :== •25in Thickness of Plate, HTS<br />
H = 18.524ft<br />
Head of Water<br />
K := 1 For AR = 0.108, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C :- 400ft'^ For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b<br />
c ■<br />
— /H<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
K-VHb ,, rr,, ...<br />
*min ■" "^<br />
Note: The stirfeners are assumed <str<strong>on</strong>g>to</str<strong>on</strong>g> be spaced evenly across<br />
C<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sp<strong>on</strong>s<strong>on</strong> shell plating with 6 stiffeners spanning 15.13'.<br />
^min = 0.28in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .28 in. The actual<br />
plate thickness is .25 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck shell plating must ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r be stiffened or have less ballast added. It should be<br />
noted,<br />
however, that some structural margin exists within <str<strong>on</strong>g>the</str<strong>on</strong>g>se calculati<strong>on</strong>s and that .28 is close enough <str<strong>on</strong>g>to</str<strong>on</strong>g> .25 in. As a result, it is<br />
possible that stiffening is not required for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck shell sp<strong>on</strong>s<strong>on</strong> plating.<br />
t_min > t_actual<br />
92
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Maximum Ballast Weight:<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7f Athwartship<br />
F := 0.4 Fore/Aft<br />
Resulting Pressure <strong>on</strong> Sp<strong>on</strong>s<strong>on</strong> Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 60ft Ht := 15.13ft<br />
Area := L • Ht<br />
P ■= 1000- •—<br />
ft^<br />
Area = 907.8ft^<br />
Maximum pressure allowed for sp<strong>on</strong>s<strong>on</strong> shell plating lAW CVN 76 Specs<br />
FN_new == ? " Area FN_new = 9.078x 10^ lb<br />
p<br />
H := H = 15.528ft<br />
Psw<br />
New Equivalent Head<br />
Loading <strong>on</strong> Shell Plating:<br />
. f 11.5<br />
a := asm<br />
U5-13<br />
a = 49.47 Ideg<br />
P := asinf-^ I P = 40.519deg<br />
pN_new = Fv_new ' cos(p) + F^jiew " '^os(a)<br />
Py new = ^ ■ Wperma<br />
V^^ical Load (Downward)<br />
FA_new = ^ • Wp^^^ Athwartship Load (Port)<br />
% new = V • Wperma " cos(p) + A • Wp^^^ • cos (a)<br />
N_new<br />
^P^^ ''^ (v.cos(p) + A.cos(a))<br />
^Perma = 281.9041<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Weight of Perma Ballast® that cannot be exceeded<br />
93
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
tjjjjn := .25in<br />
Thickness of Plate, HTS<br />
H = 15.528ft<br />
Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := 1 Assume AR remains less than .5<br />
C:= 400ft'^ For HTS, No Set<br />
b<br />
— <<br />
K-VH<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
C h<br />
''limit '■= ^min T ^ = ^^i" T = 13in<br />
L 2<br />
2<br />
KH<br />
''limit = 25-377in<br />
25.377 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners can be apart and have no plastic deformati<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> existing .25 in plating.<br />
The current stiffeners are located 26 in apart. It is recommended that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners be placed less than maximum distance apart.<br />
Therefore, adding a vertical stiffener in <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of each existing stiffener <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> shell sp<strong>on</strong>s<strong>on</strong> plating will put b at 13 in and<br />
meet <str<strong>on</strong>g>the</str<strong>on</strong>g> 25.377 in requirement-<br />
Results<br />
A combinati<strong>on</strong> of Lesser Weight Additi<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> meet <str<strong>on</strong>g>the</str<strong>on</strong>g> lOOOpsf limit al<strong>on</strong>g with adding a stiffener in <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of each existing<br />
stiffener will alleviate any structural c<strong>on</strong>cerns.<br />
94
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
a := k • P •<br />
p = pressure based <strong>on</strong> 1000 psf <strong>on</strong> sp<strong>on</strong>s<strong>on</strong> shell plating<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
''simply_supported •<br />
lc,i fi := -5 ^ values are most c<strong>on</strong>servative<br />
a := 2Qft b := Bin based <strong>on</strong> 13 in separati<strong>on</strong> between stiffeners<br />
Jlb_<br />
P = 6.944-<br />
. 2<br />
in<br />
t := .25in<br />
^max allowable= 40,000 Jb_<br />
. 2<br />
in<br />
I AW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
^simply_supported • Simply_supported<br />
,., lb<br />
^simply_supported<br />
14083<br />
in<br />
"■'7<br />
^clamped • "Clamped<br />
I ^<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding stiffeners at 13 in, <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below that of simply<br />
supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support<br />
illustrating zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship,<br />
structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r.<br />
Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress should be well below maximum allowable.<br />
^clamped<br />
^max_allowabl(<br />
95
C coefficient derivati<strong>on</strong> from beam <str<strong>on</strong>g>the</str<strong>on</strong>g>ory:<br />
Panel is c<strong>on</strong>sidered a series of beams having FIXED ends.<br />
1,3 Y-H<br />
I := — • 1 ■ t q := -^<br />
12 ^ 144<br />
12 ^ t<br />
Ox_max-~ ■ ~ P'^'^ bending now equivalent <str<strong>on</strong>g>to</str<strong>on</strong>g> Navy's standard, see Eqn 2<br />
Nx_max'288 j<br />
b_over_t := j y := 64.'^<br />
V Y VH<br />
^x max'" ^^^ without introducing K fac<str<strong>on</strong>g>to</str<strong>on</strong>g>r, used for shorter panels<br />
^ Px max-288<br />
C := —= c = 422.944<br />
353.861<br />
b over t < •<br />
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
^min ~ ^Sin Thickness of Plate, HTS<br />
H = 15.528ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := 1 Assume AR remains less than .5<br />
C := 422.944Ft'^ For HTS, No Set<br />
b<br />
—
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
a := k • P<br />
— p = pressure based <strong>on</strong> 1000 psf <strong>on</strong> sp<strong>on</strong>s<strong>on</strong> shell plating<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
"Simply^upported ■ ■ Clamped :=.5<br />
a := 20ft<br />
b<br />
p = 6.944—<br />
. 2<br />
in<br />
*^max_allowable~<br />
40,000<br />
lb<br />
. 2<br />
m<br />
blimit=26.833ir<br />
AR = 18.462<br />
t := .25in<br />
lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> Gei<br />
'^simply_supported • Simply_supported '<br />
'<br />
^_^limit^<br />
^simply_supported<br />
60000-^<br />
. 2<br />
in<br />
^clamped • Clamped ■P- V t J<br />
clamped<br />
40000^<br />
. 2<br />
m<br />
97
structural Analysis for Compartment 2-165-8-V: Ship Shell Plating<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
Perma Ballast® Data<br />
PPerma ■- 200-!^<br />
ft<br />
^"Perma.fill •= ■^'<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
lb<br />
sw<br />
ft"<br />
Compartment 2-165-8-V<br />
Density of Seawater<br />
Volume := 3969ft<br />
Wperma-=2811<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Volume of Compartment<br />
Maximum Weight of Permanent Ballast that can be added in accordance with shell plating<br />
stress calculati<strong>on</strong>s<br />
FR175<br />
FR180<br />
Main Deck<br />
9.83'<br />
2nd Deck<br />
6 Tees, spaced 26" apart (7.5#)<br />
98
FR 165 - FR 180 Transverse Bulkheads<br />
20-4# (-5")<br />
Main Deck<br />
11.5' ><br />
Stringer #6<br />
Girder<br />
Ship<br />
Shell<br />
Plating<br />
30.6# (.75")<br />
2nd Deck<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
Shell<br />
V:=1.2f Vertical<br />
A := O.li Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Inner L<strong>on</strong>gitudinal Bulkhead Plating:<br />
Wpgj^a = 6.294X 10 lb Weight of Perma Ballast®<br />
Fy := V-Wperma<br />
FA ■= AWpenna<br />
Fp:- FWpgj^jjja<br />
% ■- ^A<br />
FY = 7.868X 10 lb<br />
F^ =4.721x 10^ lb<br />
Fp = 2.518x 10^ lb<br />
Fj^=4.721x 10 lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
Normal Force<br />
99
Resulting Pressure <strong>on</strong> Inner L<strong>on</strong>gitudinal Bulkhead Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 60ft<br />
Area := L-Ht<br />
Area<br />
Psw<br />
Ht := 9.8 Jt<br />
Area = 589.8ft^<br />
P = 800.407—<br />
ft^<br />
H = 12.429ft<br />
P = 5.558-1^<br />
. 2<br />
m<br />
Equivalent Head<br />
100
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
b := —ft a := 24an AR := - AR = 0.246<br />
2 a<br />
Wual •= •'^5'" Thickness of Plate, HTS<br />
H = 12.429ft Head of Water<br />
K := 1 For AR = 0.246, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ff^ For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
b C ■<br />
— < K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
K-VH<br />
H = Head of salt water (feet)<br />
K-y/Hb<br />
t, min" p<br />
Wn = 0-52in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .52 in. The actual<br />
plate thickness is .75 in. Therefore, stiffening of <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck inner l<strong>on</strong>gitudinal bulkhead plating is not required.<br />
t min «t_actual<br />
101
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s<br />
'min '■= •'^^'" Thickness of Plate, HTS<br />
H = 12.429ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := 1 Assume AR remains less than .5<br />
C := 400ft'^ For HTS, No Set<br />
b<br />
—
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
o := kP- -<br />
p = pressure based <strong>on</strong> 95% of maximum ballast additi<strong>on</strong> I AW sp<strong>on</strong>s<strong>on</strong> stress calculati<strong>on</strong>s<br />
^imply_supported<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
"^clamped •<br />
k values are most c<strong>on</strong>servative<br />
a := 20ft<br />
P = 5.558—<br />
. 2<br />
m<br />
lb<br />
^max_allowable= 40,000—<br />
in<br />
b := 58in<br />
based <strong>on</strong> no stiffener additi<strong>on</strong><br />
t := .75in<br />
lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
■^simply_supported • ^imply_supported<br />
simply_supported 24931—<br />
. 2<br />
m<br />
^clamped • Clamped<br />
'^clamped =16621—<br />
. 2<br />
m<br />
Maximum Allowable Stress for HTS is 40,000 psi. The calcuated stresses fall well below that of simply supported and that of<br />
clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support illustrating zero stiffness<br />
and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship, structural systems can be<br />
c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural analysis<br />
is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress should be well below maximum allowable.<br />
"'clamped<br />
''max_allowabl(<br />
103
structural Analysis for Compartment 2-165-8-V: Transverse Bulkhead<br />
Frames 165,170,175, and 180<br />
Perma Ballast® Data<br />
lb<br />
P Perma :=200-<br />
ft<br />
% Perma fill ■ .9f<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
sw :=64.4^<br />
ft^<br />
Density of Seawater<br />
Compartment 2-165-8-V<br />
Volume :=3965ft^<br />
Wperma:=2811<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Volume of Compartment<br />
Maximum Weight of Permanent Ballast that can be added in accordance with shell plating stress<br />
calculati<strong>on</strong>s<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f<br />
A := 0.71<br />
F := 0.4<br />
Vertical<br />
Athwartship<br />
Fore/Aft<br />
Loading <strong>on</strong> Transverse Plating:<br />
Wpg^3 = 6.294x lO^lb Weight of Perma Ballast®<br />
Pv^=V.Wp,rma<br />
FA -■= AWperma<br />
FF^=FWpe3<br />
% •- Pp<br />
Fv = 7.868x 10 lb<br />
FA=4.721X 10^ lb<br />
Fp = 2.518x 10^ lb<br />
FN=2.518X 10 lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
Normal Force<br />
104
Main Deck<br />
Shell<br />
FR 165 - FR 180 Transverse Bulkheads<br />
20.4# (.5"<br />
11.5' ><br />
Stringer #S<br />
Girder<br />
Ship<br />
Shell<br />
Plating<br />
30.6# (.75")<br />
10.2 # {.25")<br />
2nd Deck<br />
Shell<br />
Resulting Pressure - <strong>on</strong> Transverse Plating:<br />
Compartment Dimensi<strong>on</strong>s<br />
L:= 11.5ft<br />
Area := .5LHt<br />
Area<br />
'sw<br />
Ht := 9.&m<br />
Area = 56.523ft^<br />
3 lb<br />
p = 4.454x 10 —<br />
ft^<br />
H = 69.168ft<br />
P = 30.934—<br />
. 2<br />
m<br />
Equivalent Head<br />
105
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)|<br />
The transverse plating at Frames 165, 170, 175, and 180 is stiffened by 3 vertical stiffeners and 3 horiz<strong>on</strong>tal stiffeners <str<strong>on</strong>g>to</str<strong>on</strong>g> include<br />
a vertical girder that runs from <str<strong>on</strong>g>the</str<strong>on</strong>g> Main Deck <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> shell plating above stringer #6. The largest secti<strong>on</strong> of transverse plating<br />
that is unstiffened is approximately a 24"X34.5" secti<strong>on</strong> of plate. An assumpti<strong>on</strong> was made that all vertical stiffeners are spaced<br />
equally apart. All structural analysis was performed <strong>on</strong> this secti<strong>on</strong> of plate.<br />
b := 24in a := 34.Sn AR := - AR = 0.696<br />
a<br />
Wual •= •^^" Thickness of Plate, HTS<br />
H = 69.168ft Head of Water<br />
K := .94 For AR = 0.696, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft"^ For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b<br />
—
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s<br />
t ■ := .Sttn<br />
Thickness of Plate, HTS<br />
H = 69.168ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := .94 Assume AR remains .696<br />
C := 40Qft'^ For HTS, No Set<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
b C "<br />
— < K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
K-VH<br />
H = Head of salt water (feet)<br />
''limit-<br />
24in<br />
'•mm j<br />
KH^<br />
''limit = = 25.583in<br />
25.583 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that l<strong>on</strong>gitudinal stiffeners can be located apart and have no deformati<strong>on</strong> occur <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> .5 in<br />
plating. The transverse plating at Frame 165 has 3 horiz<strong>on</strong>tal stiffeners and 3 vertical stiffeners. The current horiz<strong>on</strong>tal stiffener<br />
spacing is approximately 24" and within <str<strong>on</strong>g>the</str<strong>on</strong>g> limiting width between stiffeners. As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g> transverse plating at Frame 165<br />
does not need <str<strong>on</strong>g>to</str<strong>on</strong>g> be stiffened. Frames 170,175 and 180 are similar in design.<br />
107
Stress Calculati<strong>on</strong>s:<br />
b^2<br />
a := k-Pl — I<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
p = pressure based <strong>on</strong> 1000 psf <strong>on</strong> sp<strong>on</strong>s<strong>on</strong> shell plating<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
'Siniply_supported '■= ■'^- "^lamped •= -^ ^ ^^'"^^ ^""^ "1°^' c<strong>on</strong>servative<br />
a := 34.Sn b := 24in based <strong>on</strong> no stiffener additi<strong>on</strong><br />
P = 30.934—<br />
. 2<br />
in<br />
t := .SOn<br />
*^max_allowable~ 40,000— I AW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
2<br />
in<br />
^simply_supported ' *Simply_supported '^l<br />
b^2<br />
'^simply_supported ~ "o<br />
in<br />
2<br />
... b<br />
^clamped " '^clamped<br />
^clamped = 35636-^<br />
in<br />
Maximum Allowable Stress for HTS is 40,000 psi. The calcuated stresses falls between that of simply supported and that of<br />
clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support illustrating zero stiffness<br />
and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship, structural systems can be<br />
c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural analysis<br />
is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress should be well below maximum allowable.<br />
'^clamped*^'^ ^max_allowabl(<br />
108
structural Analysis for Compartment 2-180-6-V: Shell Plating<br />
Perma Ballast® Data<br />
PPerma^=200-^<br />
ft<br />
^"Perma_fill •= •^-<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
'sw<br />
: 64.4 lb<br />
ft<br />
Compartment 2-180-6-V<br />
Volume := 6272ft^<br />
Wperma==56a<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V := 1.2f Vertical a := asin r n.5<br />
15.13<br />
A := 0.7f<br />
F := 0.4<br />
Athwartship<br />
Fore/Aft<br />
P := asin f 9.83<br />
15.13<br />
a = 49.47 Ideg<br />
P =40.519deg<br />
Loading <strong>on</strong> Shell Plating:<br />
Wperma = ^■254x 10^ lb Weight of Perma Ballast®<br />
Fy := V • Wpgrma<br />
F^ :- A • Wpgj.j^g<br />
Fp := F • Wpgj.jjjg<br />
Fv=1.568x 10 lb<br />
F^ =9.408x 10^ lb<br />
Fp = 5.018x 10^ lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
F^ := Fy • cos(p) + F^ ■ cos(a) Fj^ = 1.803x 10^lb<br />
Normal Force<br />
109
Resulting Pressure <strong>on</strong> Sp<strong>on</strong>s<strong>on</strong> Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L:=96ft Ht:= 15.13ft<br />
Area := L • Ht Area = 1.452x 10^ ft^<br />
p<br />
P := P = 1.242x 10^ — P = 8.622—<br />
Area 2 .2<br />
It m<br />
^95% -"^ %erma_fill' ^ ^95% = ^ •179x 10 — Based <strong>on</strong> 95% Fillable Volume<br />
ft^<br />
^95%<br />
H := H = 18.315ft Equivalent Head<br />
Psw<br />
In accordance with CVN 76 Specs, sp<strong>on</strong>s<strong>on</strong> plating aft of Frame 88 shall be designed for 1000 psf. Therefore, less ballast must<br />
be added <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se sp<strong>on</strong>s<strong>on</strong> voids.<br />
1179 psf > 1000 psf<br />
110
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
Panels of plating shall be proporti<strong>on</strong>ed so as not <str<strong>on</strong>g>to</str<strong>on</strong>g> exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> breadth-thickness ratios<br />
found below:<br />
b := 26in a := lidn AR := - AR =: 0.108<br />
a<br />
^actual '•= -251" Thickness of Plate, HTS<br />
H = 18.315ft Head of Water<br />
K := 1 For AR = 0.108, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft'^ For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
b C ■<br />
— < K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
t K-VH<br />
H = Head of salt water (feet)<br />
l^.^ ■- —12t—'.— Note: The stiffeners are assumed <str<strong>on</strong>g>to</str<strong>on</strong>g> be spaced evenly across<br />
"^imn Q<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sp<strong>on</strong>s<strong>on</strong> shell plating with 6 stiffeners spanning 15.13'.<br />
t^„ = 0.278in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .28 in. The actual<br />
plate thickness is .25 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck shell plating must ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r be stiffened or have less ballast added. It should be<br />
noted,<br />
however, that some structural margin exists within <str<strong>on</strong>g>the</str<strong>on</strong>g>se calculati<strong>on</strong>s and that .28 is close enough <str<strong>on</strong>g>to</str<strong>on</strong>g> .25 in. As a result, it is<br />
possible that stiffening is not required for <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck shell sp<strong>on</strong>s<strong>on</strong> plating.<br />
t min > t actual<br />
111
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Maximum Ballast Weight:<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7; Athwartship<br />
F := O.A Fore/Aft<br />
Resulting Pressure <strong>on</strong> Sp<strong>on</strong>s<strong>on</strong> Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L:=9fft Ht:=15.1Jt<br />
P := 1000- —<br />
ft^<br />
Maximum pressure allowed for sp<strong>on</strong>s<strong>on</strong> shell plating lAW CVN 76 Specs<br />
Area := L • Ht<br />
Area = 1.452x 10^ ft^<br />
%_new ■■= P • Area F^^gw = 1 •452x 10^ lb<br />
P<br />
H := H = 15.528ft New Equivalent Head<br />
Psw<br />
Loading <strong>on</strong> Shell Plating:<br />
f 11.5<br />
a := asin 1 ■ a = 49.47 Ideg<br />
U5.13J<br />
3:=asin^- P=40.519deg<br />
%_new = Fv_new ' cos(p) + F^_„g^ • cos (a)<br />
^V_new = ^ ■ ^Perma Vertical Load (Downward)<br />
'^Ajew - A ■ ^Perma Athwartship Load (Port)<br />
%_new = V • Wperma • cos(3) + A • Wpg^ia " cos (a)<br />
N_new<br />
P^^^^(v.cos(p) + A.cos(a))<br />
^Perma ~ ^^ ^ ■0471<str<strong>on</strong>g>to</str<strong>on</strong>g>r<br />
Weight of Perma Ballast® that cannot be exceeded<br />
112
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:!<br />
25in<br />
■^min"<br />
H = 15.528ft<br />
K:=l<br />
C := 400ff^<br />
Thickness of Plate, HTS<br />
Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
Assume AR remains less than .5<br />
For HTS, No Set<br />
b<br />
— <<br />
K<br />
yfU<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
limit ■<br />
min'<br />
b = 26in<br />
- = Bin<br />
2<br />
blimit = 25.377in<br />
K • H<br />
25.377 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners can be apart and have no plastic deformati<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> existing .25 in plating.<br />
The current stiffeners are located 26 in apart. It is recommended that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners be placed less than maximum distance apart.<br />
Therefore, adding a vertical stiffener in <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of each existing stiffener <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> shell sp<strong>on</strong>s<strong>on</strong> plating will put b at 13 in and<br />
meet <str<strong>on</strong>g>the</str<strong>on</strong>g> 25.377 in requirement.<br />
Results<br />
A combinati<strong>on</strong> of Lesser Weight Additi<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> meet <str<strong>on</strong>g>the</str<strong>on</strong>g> lOOOpsf limit al<strong>on</strong>g with adding a stiffener in <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of each existing<br />
stiffener will alleviate any structural c<strong>on</strong>cerns.<br />
113
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
a := k • P • — p = pressure based <strong>on</strong> 1000 psf <strong>on</strong> sp<strong>on</strong>s<strong>on</strong> shell plating<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
'^imply_supported •= •'^- K;laniped •= -^ ^ ^^'"^^ ^""^ ""o^t c<strong>on</strong>servative<br />
a := 20ft b := 13in based <strong>on</strong> 13 in separati<strong>on</strong> between stiffeners<br />
P = 6.944—<br />
. 2<br />
in<br />
t := .25in<br />
°max_allowable'= 40,000— lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
in<br />
"'simply_supported •" 'Simply_supported ' '^ ' I T I<br />
^simply_supported ~ 14083—<br />
in<br />
'^clamped • "^clamped ' ^ ' '<br />
^clamped =9389-!^<br />
in<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding stiffeners at 13 in, <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below that of simply<br />
supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support<br />
illustrating zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship,<br />
structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r.<br />
Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress should be well below maximum allowable.<br />
''clamped^^^max.allowabU<br />
114
structural Analysis for Compartment 4-165-4-V; Deck Plating<br />
Perma Ballast® Data<br />
Pperma<br />
200^<br />
3<br />
ft"<br />
^^Perma fill :=.9f<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
sw ■ 64.4^<br />
ft^<br />
Compartment 4-165-4-V<br />
Volume :=700ft^<br />
Wpenna==621<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
3rd Deck<br />
FR 170 Transverse Bulkhead<br />
20.M{.5")<br />
8'8"<br />
4th Deck Plating<br />
20.4# (.5")<br />
4th Deck<br />
FR 165 Transverse Bulkhead<br />
HB#3 4-4'- BB#2 20.4#(-5")<br />
40.8#(1.0") 25.5#{.625")<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7f Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Deck Plating:<br />
Wperma = 1-389x10'lb Weight of Perma Ballast®<br />
Fv^=V.Wp,^3<br />
FA ■■= AWpenna<br />
Fp := FWp^j^g<br />
Fy=1.736x lo'lb<br />
F^ = 1.042x lo'lb<br />
Fp = 5.555x lo'^lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
% •= Fv Fi>j = 1.736x lo'lb<br />
Normal Force<br />
115
Resulting Pressure <strong>on</strong> Deck Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 20ft W := 4ft<br />
Area := LW<br />
Area = 80ft^<br />
P:=^ P.ZnxlO^i^ P = 15.06^<br />
Area ^2 .2<br />
It m<br />
^^95% '-"^ ^"Perma.fiir^ ^95% = ^^O^x lo'^— Based <strong>on</strong> 95% Fillable Volume<br />
m<br />
^95%<br />
H := H = 32.011ft Equivalent Head<br />
Psw<br />
The actual head for flooding of <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th deck <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 6" above <str<strong>on</strong>g>the</str<strong>on</strong>g> 2nd deck (DC Deck) will result in a head of 27.7'. This value is<br />
below <str<strong>on</strong>g>the</str<strong>on</strong>g> head calculated above of 32'. As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating must be stiffened.<br />
32 ft > 27.7 ft<br />
116
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
b := 48in a := 48in AR:=^ AR =1<br />
^actual<br />
H := 27.7ft<br />
K := .78<br />
.5<br />
C := 35Qft<br />
- .5Qiii Thickness of Plate, OS<br />
Maximum Head of Water for 4th Deck (which really implies permanent set and may still not be c<strong>on</strong>servative<br />
enough)<br />
For AR = 1, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
For OS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b<br />
— <<br />
K-VH<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
min"<br />
K-VHb<br />
tmin = 0-563in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .563 in. The actual<br />
plate thickness is .5 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th deck shell plating must ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r be stiffened or have less ballast added.<br />
t_min »t_actual<br />
117
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Maximum Ballast Weight:]<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A :- 0.11 Atiiwartship<br />
F := O.A Fore/Aft<br />
Resulting Pressure <strong>on</strong> Deck Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 20ft W := 4ft<br />
Area := L-W<br />
Area = 80ft^<br />
H = 27.7ft Based <strong>on</strong> Maximum Equivalent Head or Design Load<br />
^new '■' ^'Psw ^new ~ 12.388—<br />
in<br />
%_new ■" ^new'^^^<br />
pN_new = 1-427x10^ lb<br />
Loading <strong>on</strong> Deck Plating:<br />
F — F<br />
N_new ~ ^V_new<br />
^V new ~ ^"^Perma<br />
Vertical Load (Downward)<br />
N_new<br />
^Perma '■-<br />
V<br />
^Perma ~ 50.9681<str<strong>on</strong>g>to</str<strong>on</strong>g>r<br />
Weight of Perma Ballast® that cannot be exceeded<br />
118
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
tjni„:=.5in Thickness of Plate, OS<br />
H = 27.7ft Head of Water<br />
K - .78 Assume AR remains 1<br />
C := 350ft'^<br />
b<br />
— < •<br />
K-VH<br />
For OS, No Set<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
limit • ^min"<br />
KH<br />
^limit''<br />
■■ 42.629in<br />
42.629" is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that <str<strong>on</strong>g>the</str<strong>on</strong>g> stiffeners can be apart and have no elastic deformati<strong>on</strong> <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> .5 in plating. The current<br />
stiffeners are located 40 in apart. Therefore, according <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Navy Formula, adding a stiffener <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating will not be<br />
required IF 50 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns or less of ballast is added.<br />
Results<br />
Ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r less ballast must be added <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th deck tanks OR stiffening of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating must occur <str<strong>on</strong>g>to</str<strong>on</strong>g> be less than design load.<br />
The design load is <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated head of water for that deck. Similarly, adding a stiffener down <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck plating<br />
would alleviate any structural c<strong>on</strong>cerns. Adding a stiffener cannot, however, be d<strong>on</strong>e due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> positi<strong>on</strong>ing of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating.<br />
Welding would be required <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> bot<str<strong>on</strong>g>to</str<strong>on</strong>g>m deck plating and a watch would need <str<strong>on</strong>g>to</str<strong>on</strong>g> be stati<strong>on</strong>ed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r side of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck. The<br />
tank below this 4th deck tank is foam filled and a fire watch cannot be stati<strong>on</strong>ed. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th Deck is no l<strong>on</strong>ger an opti<strong>on</strong><br />
unless <str<strong>on</strong>g>the</str<strong>on</strong>g> ballast weight <str<strong>on</strong>g>to</str<strong>on</strong>g> be added be decreased <str<strong>on</strong>g>to</str<strong>on</strong>g> less than 50 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns.<br />
119
Stress Calculati<strong>on</strong>s: No Stiffening<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
CT := kP- -<br />
p = pressure based <strong>on</strong> 50 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast additi<strong>on</strong><br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
'^imply_supported ■" ■'-<br />
a := 20ft<br />
Pnew = 12-388-!^<br />
in<br />
'^lamped " " ^ values are most c<strong>on</strong>servative<br />
b :- 48in based <strong>on</strong> no stiffener additi<strong>on</strong><br />
t := .5in<br />
"niax_allowable= 28,000—<br />
in<br />
*^simply_supported ' "Simply.supported '^new<br />
U<br />
I AW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
/i<br />
,2<br />
^simply_supported ~ 85626—<br />
in<br />
^clamped • '^clamped'^newi<br />
j<br />
«^clamped= 57084- Jb_<br />
. 2<br />
in<br />
Maximum Allowable Stress for OS is 28,000 psi. If no stiffeners are added, <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated stress is much greater than maximum<br />
allowable stress. As a result, stiffeners must still be added <str<strong>on</strong>g>to</str<strong>on</strong>g> be less than <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum allowable stress (even with less ballast<br />
added and based off design load using maximum head of water).<br />
^clamped'^^^max_allowabl<<br />
120
Stress Calculati<strong>on</strong>s: Stiffening<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
a := kP, new<br />
p = pressure based <strong>on</strong> 50 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast additi<strong>on</strong><br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
k . , _^ j •= 7' k_i j •= .5 k values are most c<strong>on</strong>servative<br />
Nimply_supported • ■'- "^jlamped<br />
a .- 20ft b :- 24ir based <strong>on</strong> adding a stiffener down <str<strong>on</strong>g>the</str<strong>on</strong>g> nviddle of <str<strong>on</strong>g>the</str<strong>on</strong>g> deck<br />
Pnew = 12.388^ t := .5in<br />
in<br />
lb<br />
a<br />
max_allowable<br />
II ui = 28<br />
-^"'""^<br />
000—<br />
^<br />
lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs<br />
t-<br />
(Secti<strong>on</strong><br />
v<br />
100)<br />
^<br />
in<br />
^simply_supported • 'Simply_supported '^newl ^<br />
^simply_supported = 21407—<br />
. 2<br />
in<br />
^clamped • Clamped newl ^<br />
clamped 14271 lb<br />
m<br />
Maximum Allowable Stress for OS is 28,000 psi. By adding stiffeners at 24 in AND with <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong> of less ballast, <str<strong>on</strong>g>the</str<strong>on</strong>g> stress<br />
falls below that of simply supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of<br />
structural member support illustrating zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural<br />
system. On board ship, structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness<br />
between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress should be well below<br />
maximum allowable. As menti<strong>on</strong>ed previously, however, adding ballast <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th deck is not feasible due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> inability <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
stiffen <str<strong>on</strong>g>the</str<strong>on</strong>g> 4th deck.<br />
^clamped<br />
^max_allowabl(<br />
121
structural Analysis for Compartment 8-225-6-V; Shell Plating<br />
Perma Ballast® Data<br />
PPerma:=2{)0-!^<br />
ft<br />
^''Perma_fill •= ■^~<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
lb<br />
sw 64.4-<br />
ft"<br />
Compartment 8-225-6-V<br />
Volume := 28 l^t^<br />
Wperma '■= 2511<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
(Shaft Alley Bulkhead #4)<br />
14.024# (.343")<br />
Outer L<strong>on</strong>gitudinal Bulkhead<br />
/ (L<strong>on</strong>gitudinal Bulkhead #3)<br />
'^ 17.85# (.437")<br />
FR 230 Transverse Bulkhead<br />
12.75# (.3125")<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7i Athwartship<br />
F := 0.4 Fore/Aft<br />
leading <strong>on</strong> Shell Plating:<br />
FR 225 Transverse Bulkhead<br />
15.3# (.375")<br />
\A^s -^ ^stringer #14<br />
^Stringer #11<br />
^Perma = 5.622x 10^ lb Weight of Perma Ballast®<br />
Plating<br />
(.75")<br />
Pv^=V.Wp,^3<br />
FA==A-Wp,^3<br />
Fv = 7.028x 10 lb<br />
F^ =4.217x 10^ lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fp := FWp^^g<br />
R • ("27<br />
p := asm<br />
U23.<br />
a := 90deg - P<br />
Fi^:=Fvcos(p) + F^-cos(a)<br />
Fp=2.249x 10^ lb<br />
P = 12.68deg<br />
a = 77.32deg<br />
Fore/Aft Load<br />
Fj^j = 7.782x lO^lb Normal Force<br />
122
Resulting Pressure <strong>on</strong> Shell Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L := 20ft Ht := 12Sn<br />
Area := L-Hl<br />
Area = 205ft^<br />
% 3 lb lb<br />
P :=:: —^ P = 3.796X 10 — P = 26.363—<br />
Area .2 . 2<br />
ft m<br />
^95% ■= ^"Perma.fiir'f' ^95% " ^-^^^^ ^^ — ^^^^^ °" ^^^^ ^^^^^^^^ Volume<br />
ft^<br />
- It-<br />
^9'5%<br />
H := —^ H = 56ft Equivalent Head<br />
Psw<br />
123
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
b:=41in a := 24an AR := - AR =0.171<br />
a<br />
'actual :=-^Sin Thickness of Plate, HTS<br />
H = 56ft Head of Water<br />
K := 1 For AR = 0.171, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft' For HTS, No Se, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)t<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
— ^ = K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
t KVH<br />
H = Head of salt water (feet)<br />
'min •<br />
K-VHb<br />
C<br />
t„i„ = 0.767in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .767 in. The actual<br />
plate thickness is .75 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck shell plating must ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r be stiffened or have less ballast added.<br />
t_min »t actual<br />
124
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:!<br />
t ■ -.75in<br />
Thickness of Plate, HTS<br />
H = 56ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := 1 Assume AR remains less than .5<br />
C := 400ft'^ For HTS, No Set<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
b C ■<br />
_ < K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
K-y/H<br />
H = Head of salt water (feet)<br />
"limit • ^min<br />
C<br />
KH<br />
blimit = 40-08911,<br />
40.089 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that l<strong>on</strong>gitudinal stiffeners can be located apart and have no deformati<strong>on</strong> occur <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> .75 in<br />
plating. The shell plating has 2 l<strong>on</strong>gitudinal stiffeners or stringers located apporoximately 41 in apart. Therefore, stiffening of<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> existing shell plating will be required for 251 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast.<br />
125
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Maximum Ballast Weight without stiffening:<br />
trnin min := .75in<br />
b|jjjjjj := 41in<br />
Thickness of Plate, HTS<br />
Short Dimensi<strong>on</strong> of Panel<br />
K := 1 Assume AR remains less than .5<br />
.5<br />
C := 400ft' For HTS, No Set<br />
b<br />
— <<br />
t<br />
K>/H<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t - thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
Hn^ lew •<br />
f Ct ■ \<br />
min<br />
^^^■''limity<br />
H„e^= 53.54ft<br />
Pnew ■= HnewPsw ^new = 23.944^<br />
in<br />
N new ■•= • Pnp,.,Area<br />
*^new<br />
F, N new =7.068x 10 lb<br />
%_new = Fv_new-'^°s(p) + F^jg^-cosCa)<br />
'^V new ~ ^'^Perma<br />
'^A.new ~ ^'^Perma<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
%_new = VWpern,aCos(p) + A-Wpern,a-cos(a)<br />
W<br />
Perma<br />
N_new<br />
(Vcos(p) + A-cos(a))<br />
Wperma=227.9741<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Weight of Perma Ballast® that cannot be exceeded so that stiffening of <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck shell plating will not be required.<br />
126
Stress Calculati<strong>on</strong>s for 227 I<str<strong>on</strong>g>to</str<strong>on</strong>g>ns of ballast:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
P ._ y^.p -I — I p = pressure based <strong>on</strong> limiting ballast add for shell plating calculati<strong>on</strong>s<br />
new , j<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
1c . , _ j •= 7' L.1 „ j •= .5 k values are most c<strong>on</strong>servative<br />
•^imply.supported • •'- "xlamped<br />
a := 20ft b := 41in based <strong>on</strong> 41 in separati<strong>on</strong> between stiffeners<br />
Pnew=23.944i^ t := .75ii,<br />
in<br />
^max allowable= ^^' ^^— ^^^ ^'^'^ *^ General Specs (Secti<strong>on</strong> 100)<br />
in<br />
b^^<br />
'^simply_supported • 'Simply_supported '^newl j.<br />
'^simply_supported -53667 ^<br />
in<br />
^clamped ■<br />
,b^2<br />
clamped new"! ^<br />
f^clamped = 35778—<br />
in<br />
Maximum Allowable Stress for HTS is 40,000 psi. Without any stiffener additi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> calculated stress falls between that of<br />
simply supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member<br />
support illustrating zero stiffness and infinite stiffhess, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board<br />
ship, structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls below maximum allowable.<br />
^clamped*^ ''max_allowabl<<br />
127
structural Analysis for Compartment 8-225-6-V: Inner L<strong>on</strong>gitudinal<br />
Bulkhead Plating<br />
Perma Ballast® Data<br />
PP, erma<br />
lb<br />
:= 200-<br />
ft"<br />
hernia filb^^-<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
lb<br />
sw 64.4-<br />
ft<br />
Compartment 8-225-6-V<br />
Volume := 281'tft"'<br />
Wperma '■= 2271<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast based off limiting shell calculati<strong>on</strong>s<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
(Shaft Alley Bulkhead #4)<br />
14.024# (.343<br />
20<br />
Outer L<strong>on</strong>gitudinal Bulkhead<br />
A (L<strong>on</strong>gitudinal Bulkhead #3)<br />
^ 17.85# (.437")<br />
FR 230 Transverse Bulkhead<br />
12.75# (.3125")<br />
FR 225 Transverse Bulkhead<br />
15.3# (.375"<br />
-Stringer #14<br />
Z_c Stringer #11<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7f Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Inner L<strong>on</strong>gitudinal Bulkhead Plating:<br />
^Perma = 5.085x 10^ lb Weight of Perma Ballast®<br />
Fv^^VWp^^^<br />
FA -■= AWperma<br />
FP ■■= FWpenna<br />
FY=:6.356X 10 lb<br />
F^ =3.814x 10^ lb<br />
Fp = 2.034x 10^ lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
r^j: Fi^=3.814x 10 lb Normal Force<br />
128
Resulting Pressure <strong>on</strong> Inner L<strong>on</strong>gitudinal Bulkhead Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
L:=20ft Ht:=114n<br />
Area := L-Ht<br />
Area = 190ft^<br />
% 3 lb lb<br />
P •= —^ P = 2.007X 10 — P = 13.939—<br />
Area ^2 .2<br />
p<br />
H := —— H = 31.167ft Equivalent Head<br />
Psw<br />
129
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
b := 48in a := 114)n AR := — AR = 0.421<br />
a<br />
^actual :=-34311 Thickness of Plate, HTS<br />
H = 31.167ft Head of Water<br />
K := 1 For AR = 0.421,1 AW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft' For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b<br />
— < •<br />
K-VH<br />
K-VH-b<br />
t„:„ := — mm"<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
^min = 0-67in<br />
The 8th deck inner l<strong>on</strong>gitudinal bulkhead (Shaft Alley Bulkhead #4) currently has 4 vertical stiffeners spaced 4 ft apart. The<br />
minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .67 in. The actual plate<br />
thickness is .343 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck inner l<strong>on</strong>gitudinal bulkhead plating must be stiffened.<br />
t_min »t actual<br />
130
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
tj„i„:= .34311<br />
H = 31.167ft<br />
K:= 1<br />
C := 400ft'^<br />
i
Stress Calculati<strong>on</strong>s:<br />
a := kPl -<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
p - pressure based <strong>on</strong> limiting ballast add for shell plating calculati<strong>on</strong>s<br />
Simply_supported '■" •^a<br />
:= 114in b := 24-in<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
''clamped •" -^ ^ values are most c<strong>on</strong>servative<br />
based <strong>on</strong> 24 in separati<strong>on</strong> between stiffeners<br />
P = 13.939^ t := .343in<br />
. 2<br />
in<br />
lb<br />
^max_allowable= 40,000— lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
in<br />
,2<br />
^simply_supported •:= k.;. '^simply_supported .P.i^<br />
lb<br />
*'simply_supported 51182 . 2<br />
m<br />
■'clamped ■ "Clamped'"I<br />
I<br />
clamped<br />
34121-!^<br />
. 2<br />
m<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding vertical stiffeners at 24 in, this stress falls between that of simply<br />
supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support<br />
illustrating zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship,<br />
structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r.<br />
Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below maximum allowable.<br />
1
structural Analysis for Compartment 8-225-6-V; Outer L<strong>on</strong>gitudinal Bulkhead Plating<br />
Perma Ballast® Data<br />
lb<br />
PP, 'erma ■ 200-<br />
ft<br />
% Pema fill • 9f<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
sw 64.4^^<br />
ft^<br />
Compartment 8-225-6-V<br />
Volume := 2814Ft^<br />
Wperma:=2271<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
(Shaft Alley Bulkhead #4}<br />
14.024# (.343")<br />
20<br />
Outer L<strong>on</strong>gitudinal Bulkhead<br />
(L<strong>on</strong>gitudinal Bulkhead #3)<br />
17.8S# (.437")<br />
FR 230 Transverse Bulkhead<br />
12.7^ (.3125")<br />
Shell Plating<br />
30.6#(.751<br />
FR 225 Transverse Bulkhead<br />
^.. 15.3#{.3751<br />
-Stnnger #14<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=1.2f Vertical<br />
A := 0.7f Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Outer L<strong>on</strong>gitudinal Bulkhead Plating:<br />
Wpg,^a = 5.085x lO^lb Weight of Perma Ballast®<br />
Fv:=V.Wp,^3<br />
F^ := AWpg^a<br />
Fp := F-Wpg^a<br />
^N<br />
Fv = 6.356x 10 lb<br />
F^ =3.814x 10^ lb<br />
Fp = 2.034x 10^ lb<br />
F^ = 3.814X 10 lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
Normal Force<br />
133
Compartment Dimensi<strong>on</strong>s:<br />
L := 20ft Ht := 87in<br />
Area := L-Ht<br />
Area = 145ft^<br />
Area<br />
H:= ^<br />
Psw<br />
P-2.63x10^'^<br />
H = 40.84ft<br />
P= 18.264"'<br />
. 2<br />
m<br />
Equivalent Head<br />
134
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)|<br />
b := 48in a := 87in AR := - AR = 0.552<br />
a<br />
^actual :=-43'^n Thickness of Plate, HTS<br />
H = 40.84ft Head of Water<br />
K := .9S For AR = 0.552, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft"^ For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
^<<br />
t<br />
'min'<br />
K-A/H<br />
K>/Hb<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
Wn = 0-759in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .759 in. The actual<br />
plate thickness is .437 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck outer l<strong>on</strong>gitudinal bulkhead plating must be stiffened.<br />
t min »t actual<br />
135
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
^min '"^ -^^^n<br />
Thickness of Plate, HTS<br />
H = 40.84ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K := .9 Assume AR remains less than .552<br />
C:= 400ft-^<br />
For HTS, No Set<br />
b<br />
— <<br />
K-y/H<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
C h<br />
^limit ■= ^min J" b = 48in - = 24in<br />
blimit=30.392in<br />
2<br />
KH<br />
30.392 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that stiffeners can be located apart and have no deformati<strong>on</strong> occur <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> .437 in plating. The<br />
outer l<strong>on</strong>gitudinal bulkhead plating currently has 4 vertical stiffeners spaced 4 ft apart. It is recommended that a vertical stiffener<br />
be placed in <str<strong>on</strong>g>the</str<strong>on</strong>g> middle of each existing stiffener <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> outer l<strong>on</strong>gitudinal bulkhead. Therefore, adding a <str<strong>on</strong>g>to</str<strong>on</strong>g>tal of 5 stiffeners <str<strong>on</strong>g>to</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> outer l<strong>on</strong>gitudinal bulkhead will put b at approximately 24 in and meet <str<strong>on</strong>g>the</str<strong>on</strong>g> 30.392 in requirement.<br />
136
Stress Calculati<strong>on</strong>s<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
o := kP-<br />
p = pressure based <strong>on</strong> limiting ballast add for shell plating calculati<strong>on</strong>s<br />
'Simply_supported ■<br />
a := 20ft b := 24in<br />
IK<br />
P = 18.264— t := .437in<br />
. 2<br />
in<br />
lb<br />
^max_allowable= 40,000—<br />
in<br />
b = panel width<br />
a = panel length<br />
t := plate thickness<br />
h^<br />
^simply_supported • Simply_supported '^'\ ^<br />
k<br />
Clamped<br />
, j •=<br />
•<br />
5 k values are most c<strong>on</strong>servative<br />
based <strong>on</strong> 24 in separati<strong>on</strong> between stiffeners<br />
lAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
O^;<br />
simply_supported<br />
41317—<br />
. 2<br />
in<br />
^clamped • Clamped I .<br />
clamped<br />
:27544- Ib<br />
in<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding vertical stiffeners at 24 in, this stress falls below that of simply<br />
supported and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support<br />
illustrating zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship,<br />
structural systems can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r.<br />
Navy structural analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below maximum allowable.<br />
'^clamped'^^ ''max_allowabl(<br />
137
structural Analysis for Compartment 8-225-6-V; Transverse Bulkhead Frame 225<br />
Perma Ballast® Data<br />
Pp. erma<br />
200J^<br />
ft^<br />
^"Perma.fill •= ■^-<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n := 224ab<br />
Psw ■■= 64-4-^<br />
ft<br />
Compartment 8-225-6-V<br />
Volume := 2814^1^<br />
Wperma ■= 2271<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Sea water<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
{Shaft Alley Bulkhead #4)<br />
14.024# (.343 .<br />
20<br />
Outer L<strong>on</strong>gitudinal Bulkhead<br />
/ (L<strong>on</strong>gitudinal Bulkhead #3)<br />
'^ 17.85#(.437")<br />
FR 230 Transverse Bulkhead<br />
12.75# (.3125")<br />
Shell Plating<br />
30.6# (.75")<br />
FR 225 Transverse Bulkhead<br />
15.3# (.375")<br />
-Stringer #14<br />
^Stringer #11<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V := 1.2f Vertical<br />
A := O.lt Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Transverse Bulkhead Plating<br />
Wpg^3 = 5.085x 10^ lb Weight of Perma Ballast®<br />
Fv^=V.Wp,^3 Fv = 6.356x 10^ lb Vertical Load (Downward)<br />
FA ■■= AWpen„3 F^=3.814x 10^ lb Athwartship Load (Port)<br />
FF:=FWP,^3 Fp=2.034x 10^ lb Fore/Aft Load<br />
FN := Fp FN=2.034X 10^ lb Normal Force<br />
138
Resulting Pressure <strong>on</strong> Transverse Bulkhead Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
Ht:=lMn Width := 120in Dimensi<strong>on</strong>s of rectangular secti<strong>on</strong><br />
P := asinf""^"^"^! P = 12.68deg<br />
base := 120in Dimensi<strong>on</strong>s of small triangle<br />
ht := sin(p)-base ht = 26.341in<br />
Area := Ht-Width - (.5-base -ht)<br />
4 2<br />
Area = 1.21x 10 in<br />
P:=<br />
Area<br />
P<br />
H:=<br />
Psw<br />
P = 2.421x 10''—<br />
ft^<br />
H = 37.587ft<br />
P := 16.81 ^^<br />
. 2<br />
m<br />
Equivalent Head<br />
139
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
The transverse bulkhead is trapezoidal in shape with 3 vertical stiffeners at Frames 225 and 230 respectively. The transverse<br />
bulkhead is evenly divided in<str<strong>on</strong>g>to</str<strong>on</strong>g> 4 rectangular panels so that a cylindrical plate bending analysis can be performed<br />
<strong>on</strong> each panel.<br />
base := 30in Dimensi<strong>on</strong>s of small triangle<br />
ht=26.341in ht := sin(p)-base<br />
b := 3{)in a^ := 114in AR^ := — AR^ = 0.263<br />
^A<br />
aB:=114in-ht ag = 107.415iii ARg := — ARg = 0.279<br />
aQ-a^-ht ac = 100.82CHn ARp :=— ARp = 0.298<br />
^D '•'= ^C ~^^ ^D = 94.244in AR^ := — AR^ =0.318<br />
^D<br />
^actual -^ •^^^" Thickness of Plate, HTS<br />
H = 37.587ft Head of Water<br />
K := 1 For AR < 0.5, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
C := 400ft' For HTS, No Set, I AW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
b<br />
— /Hb<br />
Vin = 0.46in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .46 in. The actual<br />
plate thickness is .375 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck transverse plating at Frame 225 must be stiffened.<br />
t_min »t actual<br />
140
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
tj^„:= .37511<br />
H = 37.587ft<br />
K:= 1<br />
C := 400ft'^<br />
b<br />
— <<br />
K-VH<br />
Thickness of Plate, HTS<br />
Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
Assume AR remains less than .5<br />
For HTS, No Set<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
*'limit • min<br />
b = 30in<br />
^=15in<br />
2<br />
KH<br />
■'limit'' 24.466in<br />
24.466 in is <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum distance that vertical stiffeners can be located apart and have no deformati<strong>on</strong> occur <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> .375 in<br />
plating. The transverse bulkhead plating has 3 vertical stiffeners It is recommended that a stiffener be placed between <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
existing vertical stiffeners. Therefore, adding 4 stiffeners <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> transverse bulkhead plating will put b at approximately 15 in and<br />
meet <str<strong>on</strong>g>the</str<strong>on</strong>g> 24.466 in requirement^ ^<br />
141
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
o := k-P- —<br />
p = pressure based <strong>on</strong> limiting ballast add for shell plating calculati<strong>on</strong>s<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
•Simply.supported -^ •'^- K;lamped •= -^ ^ ^''''"^^ ^""^ "1°^' c<strong>on</strong>servative<br />
a := 114Jn b := 15-in based <strong>on</strong> 15 in separati<strong>on</strong> between stiffeners<br />
P = 16.81— t := .375n<br />
. 2<br />
m<br />
^max allowable" 40,000— JAW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
. 2<br />
m<br />
"'simply.supported • "Simply.supported '^i<br />
bV<br />
*^siniply_supported - 20172<br />
. 2<br />
m<br />
''clamped • "^clamped'" I<br />
I<br />
lb<br />
"clamped = 13448—<br />
. 2<br />
m<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding stiffeners at 15 in, this stress falls below that of simply supported<br />
and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support illustrating<br />
zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship, structural systems<br />
can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural<br />
analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below maximum allowable.<br />
"clamped*^*^ "max_allowabl(<br />
142
structural Analysis for Compartment 8-225-6-V: Transverse Bulkhead Frame 230<br />
Perma Ballast® Data<br />
lb<br />
Pp, erma<br />
:= 200-<br />
ft<br />
% Perma fill<br />
:=.9f<br />
C<strong>on</strong>versi<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n :== 224ab<br />
lb<br />
Psw ~ 64.4—<br />
ft<br />
Compartment 8-225-6-V<br />
Volume := 2814Ft^<br />
Wperma-=2271<str<strong>on</strong>g>to</str<strong>on</strong>g>n<br />
Density of Perma Ballast®<br />
Based <strong>on</strong> 95% Fillable Volume<br />
Density of Seawater<br />
Volume of Compartment<br />
Weight of Permanent Ballast<br />
Inner L<strong>on</strong>gitudinal Bulkhead<br />
(Shaft Alley Bulkhead #4)<br />
14.024# (.343'<br />
20'<br />
— Outer L<strong>on</strong>gitudinal Bulkhead<br />
/ (L<strong>on</strong>gitudinal Bulkhead #3)<br />
^ 17.85# (.437')<br />
FR 230 Transverse Bulkhead<br />
12.75# (.3125")<br />
Ship Moti<strong>on</strong> Fac<str<strong>on</strong>g>to</str<strong>on</strong>g>rs:<br />
V:=L2f Vertical<br />
A := 0.7f Athwartship<br />
F := 0.4 Fore/Aft<br />
Loading <strong>on</strong> Transverse Bulkhead Plating:<br />
Shell Plating<br />
30.6# (.75")<br />
FR 225 Transverse Bulkhead<br />
15.3#(.375l<br />
Stnnger #14<br />
7 '^stringer #11<br />
Wpgjjjjg = 5.085X 10^ lb Weight of Perma Ballast®<br />
Fy := VWp^^g<br />
PA •= ^•'^Perma<br />
Fp := FWpgrma<br />
^N'<br />
Fv = 6.356x 10 lb<br />
F^ =3.814x 10^ lb<br />
Fp=2.034x 10^ lb<br />
Fjsj = 2.034X 10 lb<br />
Vertical Load (Downward)<br />
Athwartship Load (Port)<br />
Fore/Aft Load<br />
Normal Force<br />
143
Resulting Pressure <strong>on</strong> Transverse Bulkhead Plating:<br />
Compartment Dimensi<strong>on</strong>s:<br />
Ht := 114in Dimensi<strong>on</strong>s of rectangular secti<strong>on</strong><br />
Width := 12an<br />
P := asm<br />
p = 12.68deg<br />
base := 120in Dimensi<strong>on</strong>sof small triangle<br />
ht := sin(p)-base ht = 26.341in<br />
Area := Ht-Width - (.5-base ht)<br />
Area =1.21x 10* in^<br />
P:=— P = 2.421x10^-!^ P = 16.81—<br />
Area 2 .2<br />
It m<br />
P<br />
H := H = 37.587ft Equivalent Head<br />
Psw<br />
144
Design of Plating for Surface Ships, lAW General Specs (Secti<strong>on</strong> 100)<br />
The transverse bulkhead is trapezoidal in shape with 3 vertical stiffeners at Frames 225 and 230 respectively. The transverse<br />
bulkhead is evenly divided in<str<strong>on</strong>g>to</str<strong>on</strong>g> 4 rectangular panels so that a cylindrical plate bending analysis can be performed<br />
<strong>on</strong> each panel.<br />
base := 30in Dimensi<strong>on</strong>s of small triangle<br />
ht = 26.341in ht := sin(p)-base<br />
b := 30in a^ :- 114in<br />
ARA<br />
b<br />
ARA = 0.263<br />
^B = 114in-ht<br />
^<br />
= ag - ht<br />
ag = 107.415in<br />
a^ = 100.829in<br />
ARB<br />
ARQ<br />
b<br />
^B<br />
b<br />
ARB = = 0.279<br />
ARc = = 0.298<br />
^D := ac - ht<br />
aj) = 94.244in<br />
ARD<br />
b<br />
^D<br />
ARD = 0.318<br />
tactual := -31251<br />
H = 37.587ft<br />
K:=l<br />
C:= = 400ft'^<br />
Thickness of Plate, HTS<br />
Head of Water<br />
For AR < 0.5, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
For HTS, No Set, lAW with Table I of <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
t<br />
c ■<br />
K-VH<br />
b = short dimensi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel (inches)<br />
t = thickness of <str<strong>on</strong>g>the</str<strong>on</strong>g> plate (inches)<br />
C = Coefficient that is a functi<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating material and <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> plating <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ship<br />
K = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel<br />
H = Head of salt water (feet)<br />
TTun<br />
K^Hb<br />
C<br />
^min = 0.46in<br />
The minimum thickness calculated for this secti<strong>on</strong> of plate <str<strong>on</strong>g>to</str<strong>on</strong>g> meet Navy Structural Standards with no set is .46 in. The actual<br />
plate thickness is .3125 in. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> 8th deck transverse plating at Frame 230 must be stiffened.<br />
t min »t_actual<br />
145
Calculati<strong>on</strong>s <str<strong>on</strong>g>to</str<strong>on</strong>g> Determine Strength Correcti<strong>on</strong>s:<br />
t^jp := .3125n Thickness of Plate, HTS<br />
H = 37.587ft Head of Water (With new head of water calculated using maximum allowable ballast additi<strong>on</strong>)<br />
K :- 1 Assume AR remains less than .5<br />
C := 400ft'^ For HTS, No Set<br />
b c •<br />
—
Stress Calculati<strong>on</strong>s:<br />
k = coefficient that depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> plate edge c<strong>on</strong>diti<strong>on</strong>s,<br />
aspect ratio (AR) of <str<strong>on</strong>g>the</str<strong>on</strong>g> panel, and positi<strong>on</strong> of point being c<strong>on</strong>sidered<br />
a := kP- -<br />
p = pressure based <strong>on</strong> limiting ballast add for shell plating calculati<strong>on</strong>s<br />
'^imply_supported •<br />
a := 114in b :- 15-in<br />
lb<br />
P ^ 16.81- t := .3125n<br />
. 2<br />
in<br />
lb<br />
"max allowable= 40,000-<br />
m<br />
b = panel width<br />
a = panel length<br />
t = plate thickness<br />
^simply_supported ■ 'Simply_supported<br />
Ic , j •= 5 k values are most c<strong>on</strong>servative<br />
*t;lamped •<br />
based <strong>on</strong> 15 in separati<strong>on</strong> between stiffeners<br />
I AW with <str<strong>on</strong>g>the</str<strong>on</strong>g> General Specs (Secti<strong>on</strong> 100)<br />
I ^<br />
>2<br />
Jb_<br />
simply_supported 29048-<br />
. 2<br />
in<br />
'clamped • Clamped<br />
I ^<br />
'clamped<br />
Jb_<br />
19365-<br />
. 2<br />
m<br />
Maximum Allowable Stress for HTS is 40,000 psi. By adding stiffeners at 15 in, this stress falls below that of simply supported<br />
and that of clamped. Simply supported and clamped structural cases are idealizati<strong>on</strong>s of structural member support illustrating<br />
zero stiffness and infinite stiffness, nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r of which exists in any real-world structural system. On board ship, structural systems<br />
can be c<strong>on</strong>veniently approximated by <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r case, but in fact have stiffness between <strong>on</strong>e or <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Navy structural<br />
analysis is based off clamped ends, <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> stress falls well below maximum allowable.<br />
clamped ^«a, "max_allowabl<<br />
147
Appendix F: Final POSSE Modeling Results<br />
148
__ — __ — """ " *c;<br />
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s<br />
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r-. f-><br />
ai<br />
Appendix G: Final Cost Estimati<strong>on</strong> Data and Worksheets<br />
Provided by Norfolk Naval Shipyard Structural Engineering and Planning Office (Code 256)<br />
150
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u<br />
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ON 1—1<br />
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u Si<br />
M o<br />
MATERIAL WORK SHEET<br />
PERMA BALLAST® INSTALLATION •<br />
(This work sheet was created for <str<strong>on</strong>g>the</str<strong>on</strong>g> final costing estimati<strong>on</strong> due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> lesser<br />
I<str<strong>on</strong>g>to</str<strong>on</strong>g>n additi<strong>on</strong> for each Z"'' deck void, thus requiring compartment 2-250-4-V tO|<br />
be utilized)<br />
SHOP PC# MATERIAL STOCK NO. QTY SS/PUR COST<br />
SPONSON STIFFENING:<br />
2-250-4-V<br />
llSl 003 5" X 4" ANGLE (7.5#LF) 9520-00-277-5978 225 $6.46/FT $1,454<br />
71AA 004 PAINT $1,200<br />
74YY N/A BLAST AND PAINT FACILITY $4,500<br />
ALL N/A CONSUMABLES $2,217<br />
TOTAL MATERIAL COSTS: $9,371<br />
TOTAL MATERIAL WEIGHT:<br />
4,470 #'S<br />
152
MATERIAL WORK SHEET<br />
PERMA BALLAST® INSTALLATION<br />
(This work sheet was created for <str<strong>on</strong>g>the</str<strong>on</strong>g> final costing estimati<strong>on</strong> due <str<strong>on</strong>g>to</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
stiffening required for <str<strong>on</strong>g>the</str<strong>on</strong>g> 8^^ deck and is not reflected <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> previous<br />
estimate page)<br />
SHOP PC# MATERIAL STOCK NO. QTY SS/PUR COST<br />
BHD STIFFENING: 8"" DECK<br />
llSl 001 5" X 4" ANGLE (7.5#LF) 9520-00-277-5978 120 $6.46/FT $775<br />
71AA 002 PAINT $1,000<br />
74YY N/A BLAST AND PAINT FACILITY $2,400<br />
ALL N/A CONSUMABLES $250<br />
TOTAL MATERIAL COSTS: $4,425<br />
TOTAL MATERIAL WEIGHT:<br />
900 #'S<br />
153
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