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

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-80-struetion for the aluminum hull ship.be used.Schedule 40 aluminum piping shouldThe steel hull ore carrier was fitted with independent potable waterand sanitary water systems. The potable water system was made of coppertubing with bronze valves and fittings. The sanitary water system wasmade of 90-10 copper nickel alloy tubing with bronze valves and fittings.For the aluminum ship it is recommended that freshwater be used forflushing and the sanitary supply system be combined with the potable watersystems. Although this would require an increase in the capacity of thedistilling plant, the total cost would be reduced. In addition, the pipingsystem should be made of PVC or aluminum, Schedule 40, whichever is themore economical.The ship will be fitted with two compressed air systems, a 4,00PSIsystem for diesel engine starting and a 100 PST system for ship service.The diesel engine starting air system should be of all steel construction,to suit the high operating pressures. The low pressure ship service airsystem should be of all aluminum construction, because of exposure to saltladen air and multitude of contacts with the aluminum structure. Schedule40 aluminwn piping probably will be satisfacto~ for this 100 PSI airsystem.pumps - Pumps will be required to handle heavy fuel oil (Eunker C),diesel oil, lubricating oil, fresh water and seawater.Steel is recommended for oil pumps, in order to meet U. S. Coast GuardRegulations, and because the piping systems are steel. Nodular iron maybe used for the pump casings.Casings - Steel or Nodular IronRotow - Steelshafts - SteelFreshwater piping systems are to be either steel or PVC. Standardmaterials should be used for the fresh water pumps. The materials are:Casings - Bronze - Composition GImpellers - Bronze - Composition G,Shafts - Steel with K Monel SleevesFor the sea water pumps, bhe liquid handled is a good electrolyte,and aluminum should be preferably used. However, aluminum pumps are notreadily available and, if used, the metal does not have adequate erosionresistant properties for this service. Also, for the seawater serviceand fire service the piping materials are not compatible. Therefore, forthese pumps and the ballast pumps the recommended materials are:Casings - Bronze - Composition GImpelleH - MonelShafts - I%nel with K Plmel SleevesFor the bilge pumps, the liquids handled include seawater and thepiping material recommended is aluminum. As noted above, aluminum pumpsare not considered practical. The Pws cotid be made of a suitablestainless steel. However, it would appear to be more economically feasibleto use pumps made of the same materials as recommended for the sea waterpumps ad provide extra heavy waster pieces at the piping suction anddischarge connections.
LSEA CHESTS-81-Sea chests and overboard discharge connections should be made of castor fabricated aluminum of the same composition as the hull material. Aluminumpipe of heavy wall construction may be used for overboard dischargeshell connections.Cuts in the shell plating in way of the sea chests and overboarddischarges should be compensated for by the use of heavy insert plates,since pitting has been obse~ed in way of overboard discharges on someexisting aluminum hulls.Suction sea chests should be fitted with portable 304 or 316 stainlesssteel or approved type reinforced plastic strainer plates with 1/2 inch x3 inch or 4 inch long slots placed in a fore and aft direction. All strainerplates must be recessed in such away as to be removable with no part of theplate or securing studs and nuts projecti~ beyond the shell. All strainerplates should be secured in place with 304 or 316 stainless steel studsand nuts. All sea suctions should be fitted with the usual venting and airand steaming out connections.If 2S nickel - 20 chrome sea valves are used, aluinum waster insertpieces should be i~talled in each sea chest and overboard discharge connection.If aluminum alloy sea valves are used then aluminum insert wasterpieces am not required.SUPPORTS FOR PIPING AND MACHINERYPiping Supports - All dissimilar metal piping systems supports connectedto the alwninum hull st~cture sho~d be insulated from same. Non-absorbenttype insulating materials such as plastic electric tapes, butyl rubber tapes,strips and sheets, and neoprene strips or sheet should be used as a liningbetween the pipe and the aluminum hanger.Deck Mounted Machinery Supports - Most of the deck mounted machinerysuch as winches, anchor windlass, etc. are made of cast or fabricationsteel parts, including the subbase which is normally bolted to a steelfoundation. On the aluminum hull ship these foundations will be made ofaluminum. Since it is not economically feasible to provide deck machinerywith aluminum base plates, the joint must be insulated.For light weight machine~ or fittings, all Taying surfaces should becleaned and primed with zinc chromate. A butyl rubber type compoundcoating should be applied tO the underside of the machine~ or fitting baseplates and allowed to dry. When the machinery or fitting is about to beinstalled, a second coat of such a compound should be applied. When themachinery or fitti~ is bolted down, a quantity of this coating will besqueezed out around the periphery of the base plate, and this excessmaterial should be worked and formed into a large fillet thereby providingan effective seal. The bolting must be carefully considered and for deckservice the use of 304 or 316 staifless steel bolting can be justified. I-fcarbon steel bolting is used, it should be aluminized, galvanized orcadm.i~ plated and plastic or neoprene bushings and washers should be used.AS long as sea water spray can be kept out of the joint, no corrosion willoccur. For this reason absorbent type materials should never be used andextreme care shofid be t~en to m~e we bolted connection weathertight.
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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
Page 13:
art in fabricating and maintaining
Page 16 and 17:
MONTEROSSO GRANA /17VALGRANA / CARA
Page 18 and 19:
-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
Page 26 and 27:
-16-l?igures5, 6, 7 ati 8 present f
Page 28 and 29:
-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 86 and 87: -76-(e)The steel piping must be of
Page 88 and 89: -78-Other Piping Systems and Valves
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
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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