design considerations for aluminum hull structures - Ship Structure ...

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-106-such as iron ore, on two of the three legs, the spread between the RFR of’the steel and aluminum ships would be reduced.In an effort to evaluate these factors, an optimistic aluminum shipmodel has been established incorporating the following changes:(a)(b)(c)(d)(e)The 2S per cent labor differential has been eliminated.One-half of the 43s ton fatigue allowance has been eliminated.The 100 ton abrasion.allowance on the tank top and wing bulkheadshas been eliminated.Fire protection for the deckhouse has been modified per ItemS previously discussed.A three leg voyage with weight-sensitive cargoes carried on.two legs over distamces of 4000, 84OO and 12,000 miles havebeen assumed, with ship life of 20, 25 and 30 years, to beconsistent with previous studies (Table 28).The reduction in first cost of the ship is $1,600,000 for singleship procurement, and the available deadwight has been increased by 360tons ● Thus the 7-1/2 per cent increase in available deadweight of the baselineship increases to about 8-1/2 per cent.The three-leg voyages were considered with the following assumptions:oRound voyage distances, ship life and number of shipspurchased are identical to the figures of Table 28.0 Average Annual Costs for all items which do not vary withacquisition cost are identical to the two-leg voyage.This may not be entirely accurate with regard to such itemsas fuel costs but it is felt that this discrepancy will notmaterially affect the final results.oSince cargo is carried on two of three legs instead of one oftwo legs, annual cargo carried will increase by 33 per centover the values listed in Table’28.0 An additional increase of 1 per cent for cargo carried overthe two leg voyage as listed in Table 28 was assigned to thealuminum vessel because of increased cargo deadweight due tothe reductions in lightship.ooSalvage value of the aluminum vessel was reduced directly inproportion to changes in material weight of the vessel asoriginally conceived+Owners Investment costs, i.e., non-depreciable costs in.curred during construction, were assumed independent ofacquisition costs.As indicated in Table 29 and Figure 23, the steel bulk carrier haslower RFR’s than,the aluminum ship for equal life spans, even for thishighly optimistic case.
TABLE 29 Comparison of Steel and Aluminum BulkCarriers ( C?za2Zenger Class) Three-Leg VoyagesCaseNumberShip Life(Years)No. of ShipsPurchasedStrictureMaterialRound VoyageDistanceAnnual cargo&rried-L.T.RequiredF&eight RateWhip NetInvestment55)56)57)58)59)60)61)6z}63)64)65)66)67)68)69j70)71)72)20202025252530;;2020202525253030301steelSteelSteelSteelSteelSteelSteelSteelSteelAluminumAluminumAluminumAluminumAluminumAluminumAluminumAluminumAluminum4,0008,40012,0004,goo8,&0012,0004,0008,40012,000:,;:12;9004,0008,40012,0004,0008,40012,0001,338,460690,981483,6011,254,806679,0h2482,3911,?54,806679,042b82, 3911,447,155738,87352S,6U~,447,765738,873525,6hb1,447,?85738,873525,644$2.63 per ton5.127.172●434.746.6b2.3I4.486.272.68;.;:2:63;.;;2:625.067.10$14,520,406$14,520,4c6$14,520,1K36$14,745,466$!4,745,466$14,7M,466$14,745,466$14,745,466$111,745,466$16,1J67,612$16,467,612$16,467,612$?6,667,612$16,667,612$16,667,612$16,667,612$16,667,612$16,667,6?2* ship price + merfs Invest. Costs - Salvage Value
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CONTENTSI.. II.III.Iv.v.VI ●VII.I
Page 9 and 10:
LIST OF FIGURES(Cent’d)FIGURE NO.
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I. INTRODUCTIONThis report summariz
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art in fabricating and maintaining
Page 16 and 17:
MONTEROSSO GRANA /17VALGRANA / CARA
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-8-Numerous references have been re
Page 20 and 21:
.10.TABLE 2. Mechanical Properties
Page 22 and 23:
TABLE 2 Mechanical Properties of Al
Page 24 and 25:
TABLE 3 Mechanical Property Limits
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-16-l?igures5, 6, 7 ati 8 present f
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-18-ti-’”’-”-””””-L
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-20-60 .r---.— ..,.— -——,L-
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.22-each stress level, rate of load
Page 34 and 35:
-24-!Z456-H321 = 0.485083-H321 = 0.
Page 36 and 37:
-26-(c)Members with partial or cont
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-28-AllOyS 5083 and 54.56(~ content
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-30-The previous paragraphs have de
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-32-The problem of cargo hold abras
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-34-The question of residual stress
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.36-Each alloy was given a relative
Page 48 and 49:
-38-GENERAL OBSERVATIONSFYior to a
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-40-The question of comparative imp
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-42-(d)(e)Poor quality welds due to
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-44-The ABS criteria noted above we
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-46-DNV would consider fatigue in e
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-48-is less, for the exposed side s
Page 60 and 61:
Equation (2):-50-Hu1l SMa~um = Hull
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-52-Another aspect of vibrations wh
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-54-000000000Bottom Shell PlateSide
Page 66 and 67: -56-at the deck and keel. This stre
Page 68 and 69: -58-AT is the change inUT= Thermal
Page 70 and 71: -60-SUl@!ARYAll parties contacted f
Page 72 and 73: -62-(c)(d)(e)(f)T~e exterior side o
Page 74 and 75: TABLE 12 Aluminum Bulk Carrier - Su
Page 76 and 77: .66-INSUT.ATION AND SHEATHINGShell8
Page 78 and 79: -68-(b)(c)(d)(e)(f)(g)(h)(i)(j)At l
Page 80 and 81: -70-IIF.INSTALLATION OF SYSTEMS AND
Page 82 and 83: Rudder Assembly -carrier should be
Page 84 and 85: -74-(b)MechanicalTensile Strength 6
Page 86 and 87: -76-(e)The steel piping must be of
Page 88 and 89: -78-Other Piping Systems and Valves
Page 90 and 91: -80-struetion for the aluminum hull
Page 92 and 93: -82-Large heavy type machine~ must
Page 94 and 95: suffers attack in an alkaline envir
Page 96 and 97: -86-REPAIRSObtaining proper repairs
Page 98 and 99: -88-The design of the midship s~cti
Page 100 and 101: -90-assuming the increase is applic
Page 102 and 103: LIGHT SHIP WEIGHT ESTIMATE-92-In or
Page 104 and 105: -94-TABLE 20 Aluminum Bulk Carrier
Page 106 and 107: TABLE 22 Trim and StabilityFull Loa
Page 108 and 109: -98-TABLE 24 Price of Steel Bulk Ca
Page 110 and 111: GaseNumber. . . -.,- .TABLE 27 Comp
Page 112 and 113: -1o2-TABLE 28CarriersComparison of
Page 114 and 115: 12 ---n..T.[T7%l,=LEGS IU ORF=ErY
Page 118 and 119: -108-7)is,zg~ gg~5e mzz~E’4E!~K2j
Page 120 and 121: -11o-(a)(b)(c)(d)Inerting system fo
Page 122 and 123: -112-fatigue, particularly in the p
Page 124 and 125: -114-2k* Installation of Systems an
Page 126 and 127: -116-LIST OF REFERENCES(7)Fatigue P
Page 128 and 129: -11.8-LLST OF REFERENCES(Cent’d)(
Page 130 and 131: -120-ADDITIONAL SOURCES OF INFORMAT
Page 132 and 133: -122-redistribution of the still wa
Page 134 and 135: -124-APPENDIX BEXCERPTS FROMRULES A
Page 136 and 137: -126-92.07-10(d)(~) Interior stairs
Page 138 and 139: -128-~gE1+0102030- .. ..—405060
Page 140 and 141: ectintyclassification4KEYWORDSROLEL
Page 142: SHIP STRUCTURE COMMITTEE PUBLICATIO
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