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

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-76-(e)The steel piping must be of Schedule 80 thickness to providereasonably long life in the sea water environment.A galvanized steel pipe system with galvanized steel or galvanizednodular iron valves has the advantage of being more compatiblewith thealuminum structure and reduces the corrosion effect of galvanic couple.However, this protection may last only a year since the zinc will wasteaway. Therefore, the protection of the aluminum structure suggested forthe black steel system is also necessary for the galvanized steel system.The installed cost of this system will be somewhat higher than for theblack steel system.A fiberglass reinforcedplastic pipe system has the advantage of thematerial being inert. IhiLkheadpenetrationswould be with flanged aluminumspools. Valves could be either aluminum or 304 or 316 stainless steel. Thefiberglass pipe can not be bent.and only a few shipboard installationswithU. S. Coast Guard approval have been made. U. S. Coast Guard approvalwould have to be obtained.A PVC coated steel pipe system requires both the inside and outside ofthe pipe to be coated in order to provide full protection to the aluminumstructure. Steel pipe systems with inner PVC lining only are used quiteextensively on shore installationswhere contaminationof the productibeinghandled must be prevented, or where the product is quite active in attackingmetals. It has the disadvantageof being costly, must be purchased in fixedlengths, can not be bent, and the coating is subject to mechanical damage.AqY break in the coating will cause rapid corrosion of the steel.An 18-8 stainless steel pipe system has the advantage of beingcompatiblewith the aluminum structure, can be readily bent and welded andis acceptable to the U. S. Coast Guard. It has the disadvantage of h~ghinitial cost.A 90-10 copper nickel alloy is excellent for use in sea water applicationsbut has the basic disadvantage that it is not compatiblewithaluminum and must be insulated and protected similar to the steel systemsand, in addition, maw heavy wall waster pieces are required.An estimate of piping materials, quantities and costs has been madeof the ballast system within the ballast tanks, Table 14. Certain itemswhich are common to all systems such as bulkhead penetration spools, pipehangers and valve reach rods have not been included. Installationcostsare not included.The welding, fabrication and assembly costs of the aluminum, carbonsteel, 90-10 copper nickel alloy and 18-8 stainless steel piping systemsare assumed to be approximatelyequal and the assembly costs of the plasticand PVC lined steel systems should be somewhat less.As indicated in Table lb it can be seen that the fiberglass reinforcedplastic pipe system is the lowest in material costs as well as having theadvantage of being compatiblewith the aluminum hull structure. Maintenanceof this plastic material for the life of the ship should be very low in cost.It is recommended that this plastic material be used for ballast service inthe ballast tank provided it is acceptable to the American Bureau of Shippingand U. S. Coast Guard. Nodular iron or bronze valves insulated from thehull can be used. If this plastic material is not acceptable to the AmericanFiureauof Shipping and U. S. Coast Guard then considerationshould begiven to the use of an all aluminum ballast system.
TABLE 14 Material Cost - Ballast System (Dollars U.S.)Steel PipeFiberglass PvcBlack Galvanized Reinforced Coated Stainless S*ainlesMaterial Aluminum Steel Steel. Plastic and Lined Steel SteelSpec. 6061 T6 A~3 AS3 AISI 30h AISI 304Schedule 40 80 80 10 40Type Seamless Butt hltt lbBondstrandJl Flesisto- Seamless SeamlessWeld Weld or equal flex PP400 Ft 8“ IPS Tipe 2,940 2,962 3,554 3,180 7,900 4,744 12,7322000 Ft 12’tIPS Pipe 31,S8S 22,893 27,442 29,oOO 59,5’00 41,740 124,600Bhd PenetrationCorms. 31,585’ 22,893 27,4112 2,9,000 59,500 41,740 124,6008“ Alum Spool(Was%erPiece) - 3,000 3,00012’1Alum Spool(l$asterPiece) - 12,600 12,6008“ Flanges (92) 4,048 3,220 3,X3 1,509 Included 5,300 5,300in Pipe12° Flanges (38) 5,168 2,280 2,55’7 1,638 Included 6,2s0 6,2s0in Pipe8“ Valve (23)12” Valve (1)8’JElls (37) 3,330 1,338 1,769 2,s66 6,384 2,295 4,1011211E1ls (82) 21,320 8,282 10,783 8,930 28,700 22,796 3S,42412” Tees (20) 20,320 3,380 4,28o 7,2)J8 9,200 15,000 18,180CathodicProtection 3,400 3,4008“ Couplings(4) .58 -12~1Couplings(18) 445 -Total Cost 88,7I1 63,405 72,936 5’4,57L 111,684 98,12s 207,!5’8
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CONTENTSI.. II.III.Iv.v.VI ●VII.I
Page 9 and 10:
LIST OF FIGURES(Cent’d)FIGURE NO.
Page 11 and 12:
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
Page 30 and 31:
-20-60 .r---.— ..,.— -——,L-
Page 32 and 33:
.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
Page 38 and 39: -28-AllOyS 5083 and 54.56(~ content
Page 40 and 41: -30-The previous paragraphs have de
Page 42 and 43: -32-The problem of cargo hold abras
Page 44 and 45: -34-The question of residual stress
Page 46 and 47: .36-Each alloy was given a relative
Page 48 and 49: -38-GENERAL OBSERVATIONSFYior to a
Page 50 and 51: -40-The question of comparative imp
Page 52 and 53: -42-(d)(e)Poor quality welds due to
Page 54 and 55: -44-The ABS criteria noted above we
Page 56 and 57: -46-DNV would consider fatigue in e
Page 58 and 59: -48-is less, for the exposed side s
Page 60 and 61: Equation (2):-50-Hu1l SMa~um = Hull
Page 62 and 63: -52-Another aspect of vibrations wh
Page 64 and 65: -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 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 116 and 117: -106-such as iron ore, on two of th
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
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-126-92.07-10(d)(~) Interior stairs
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-128-~gE1+0102030- .. ..—405060
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ectintyclassification4KEYWORDSROLEL
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SHIP STRUCTURE COMMITTEE PUBLICATIO
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