A Solution to the Inherent List on Nimitz Class Aircraft Carriers

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• Testing of all accesses • Removal and reinstallation of any interferences • Patching and repair of deck coverings It was assumed that <strong>the</strong> 2"'' deck would require structural modifications due <strong>to</strong> thinner shell plating on <strong>the</strong> sponsons (compared <strong>to</strong> thicker hull shell plating found on <strong>the</strong> 8"' deck voids). Two sponson voids were analyzed in depth for cost estimation purposes, 2-165-8-V and 2-180-6- V. All production and material costs were based on prepping and work on <strong>the</strong> entire tank. As a result, <strong>the</strong> 2"'* deck void costs are much higher than <strong>the</strong> 4"* and 8* deck voids due <strong>to</strong> <strong>the</strong>ir size. Similarly, a thumb rule was applied <strong>to</strong> <strong>the</strong> T"^ deck voids when filled <strong>to</strong> 95% and no canning pate work was required. The <strong>to</strong>tal structural work, for both production and material costs, is half <strong>the</strong> cost of <strong>the</strong> canning plate work. These cost estimates do not take in<strong>to</strong> account relocation of existing utilities that may be running through <strong>the</strong> spaces. An analysis was performed, however, that determined that ballasting <strong>the</strong>se selected tanks would have little, if any impact on <strong>the</strong> tanks, and that relocation of utilities would probably not be required. Table 2 is an example cost comparison of <strong>the</strong> preliminary cost estimation results found. Production and material costs are <strong>the</strong> same regardless of <strong>the</strong> density of <strong>the</strong> ballast being used. Table 2: Deck Location Cost Comparison 2nd Deck 4th Deck 8th Deck 2-165-8-V 2-180-6-V All Voids All Voids Volume (ft') 3,969 6,273 approx. 600 approx. 1,000 Production Costs $328,704 $525,958 $21,186 $21,186 Material Costs $22,126 $35,402 $500 $500 Weight Added a<strong>to</strong>n) 4.71 7.54 0 0 32
All fur<strong>the</strong>r costing calculations for <strong>the</strong> 2°'' deck voids less than 95% filled were <strong>the</strong>n performed as a percentage of <strong>the</strong> entire tank. For example, if a 2"'' deck sponson void was <strong>to</strong> be filled 22%, <strong>the</strong>n <strong>the</strong> corresponding voids production and material costs were multiplied by 22%. This was allowable because of <strong>the</strong> nature of <strong>the</strong> geometry of <strong>the</strong> 2°'* deck voids as shown in Figure 1. Sponson void 2-165-8-V runs 60 feet long and sponson void 2-180-6-V runs 96 feet long. A detailed production and material cost breakdown for <strong>the</strong> 36 options mentioned is located in Appendix C. The worksheets used <strong>to</strong> perform <strong>the</strong>se cost estimations are also located in Appendix C. A complete preliminary cost comparison was <strong>the</strong>n performed for <strong>the</strong> 2° , 4', and 8* decks. This comparison provides <strong>the</strong> following: • Total Cost o Production cost o Material cost o Perma Ballast® cost • Total Weight (L<strong>to</strong>ns) o Material Weight o Perma Ballast® Weight • A KG This decision making cost comparison revealed that <strong>the</strong> 200 Ib/ft^ density Perma Ballast® was much more economical than <strong>the</strong> 325 Ib/ft^ density Perma Ballast®. It takes nearly <strong>the</strong> same amount of ballast <strong>to</strong> affect each incremental degree change on <strong>the</strong> same deck regardless if using <strong>the</strong> 200 Ib/ft^ or 325 Ib/ft^. Although <strong>the</strong> number of tanks required <strong>to</strong> ballast with 200 Ib/ft^ was higher, it was still more cost effective <strong>to</strong> use <strong>the</strong> 200 Ib/ft^ density ballast due <strong>to</strong> <strong>the</strong> price per I<strong>to</strong>n of <strong>the</strong> 325 Ib/ft^ ballast. The 325 Ib/ft^ ballast has steel shot added <strong>to</strong> it <strong>to</strong> help achieve its high 33
Page 1 and 2: A Solution <strong
Page 3 and 4: A Solution <strong
Page 5 and 6: Table of Contents Abstract 3 Acknow
Page 7 and 8: 1.0 Introduction 1.1 Motivation Air
Page 9 and 10: class. Changes to
Page 11 and 12: classified into fo
Page 13 and 14: o Control the KG g
Page 15 and 16: the intact stabili
Page 17 and 18: for ships propulsion, respectively.
Page 19 and 20: combined with the
Page 21 and 22: 1.3.7 Ballast Addition 1.3.7.1 Wate
Page 23 and 24: 2% entrained air (by volume) in <st
Page 25 and 26: Tank name Tank volume Ballast type
Page 27 and 28: was successfully performed and <str
Page 29 and 30: of each tank's location was added,
Page 31: 2.3 Preliminary Decision-Making Cos
Page 35 and 36: 2.4 Structural Analysis One tank on
Page 37 and 38: this pressure. This resulted in a r
Page 39 and 40: 2.4.1 Structural Modifications 2.4.
Page 41 and 42: Main Deck Shell FR 165 - FR 180 Tra
Page 43 and 44: 2.4.1.3 Modifications to</s
Page 45 and 46: 3.1 Final POSSE Results The minimum
Page 47 and 48: Table 6: Final Cost, Weight Additio
Page 49 and 50: Corrosion coupons are placed in all
Page 51 and 52: 5.0 Recommendations 1. As can be se
Page 53 and 54: References [I] Design Data Sheet 07
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structural Analysis for Compartment
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Resulting Pressure on Sponson Plati
Page 93 and 94:
Calculations to De
Page 95 and 96:
Stress Calculations: k = coefficien
Page 97 and 98:
Page 99 and 100:
FR 165 - FR 180 Transverse Bulkhead
Page 101 and 102:
Design of Plating for Surface Ships
Page 103 and 104:
Page 105 and 106:
Main Deck Shell FR 165 - FR 180 Tra
Page 107 and 108:
Calculations to De
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Calculations to De
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Calculations to De
Page 121 and 122:
Stress Calculations: Stiffening k =
Page 123 and 124:
Resulting Pressure on Shell Plating
Page 125 and 126:
Calculations to De
Page 127 and 128:
Stress Calculations for 227 I<stron
Page 129 and 130:
Resulting Pressure on Inner Longitu
Page 131 and 132:
Calculations to De
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Stress Calculations k = coefficient
Page 139 and 140:
Resulting Pressure on Transverse Bu
Page 141 and 142:
Calculations to De
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__ — __ — """ " *c; 1— ai S s
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o ON H 00 ^ ^ o > o -o B u H r^ 00
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MATERIAL WORK SHEET PERMA BALLAST®
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A Solution to the Inherent List on Nimitz Class Aircraft Carriers

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