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

-37-U13• OPERATIONS OF EHf3TING.AL~SHIPSAt this times there are inany vessels of variuus types h semricewhich are constructed either partially or wholly of aluminum alloys.The service experience gahed with these vessels ~ extrem@lY h~pfilin predicting the long-tern performance of an aluminum hull bulk carrier,and ih avoiding problems which were incorporated in early designs.On& of the fbndarm%ltal chall~es in such a study is to separateprbble~ Which ars inhdrent to the material from thdse which result fromlack of ~perience, improper design or pdor worlunanship, and then to‘predict which are readily solved and which might reasonably be e=ectedto occur under n@mal ship buildimg or operational environments.k conducting this phase of the study, the followiug primary souraesof information were considered:(a){b)(c)(d)(s)(f)(E)U. S. Navy experience with deckhouses on destroyer typevessels.U. S, Navy e~erience with alumipum p~~gunboais, landtigcraft, “SWIFT” patrol boats and hydrofoils.~. % Goast”duard experimce with aluminum decldlouses onHAMILTON class cutters and others.Alumimm deckhouses on odean liners and cargo ships.The aluminl-lmcargo vessel INDEFIEliDENCE,operated in the-bbean S&a.The aluminum trailership SACAL BORINGANO operated between‘Caribbean ports and Ilortda.Altiminu~ cmtw boats andiishing craft.(h)Specializedap’plica’tiofisr suoh as barges, lNG tanks, etc~.In evaluating the performance of these Vwselsj all available publishedreports were reviewed and in-depth discussions were held with owners,operators snd builders,to determine the perfomace of aluminum alloystructures in a marine environment. Since much of the data derived inthese discussions is consider~d proprietary, it will be necessary to presentgeneral comments and conclusions , without citing spectiic examples. Howevergwhere a speaific obsemation appears to be unique to a patiicularservice pr set of circumstances, it will be so presented.In general,this review has been limited to applications in which ~000 series alloysand state-of-the-art design and fabrication techniques have been incorporated.Thus, for example, early problems with welded 6061-T6 deckhouseson Navy dstroyers have not been specifically considered. The problemsassociated with these deckhouses have been well documented and have beenavoided in subsequent designs. They.n~ad no% be rei:te~ated as part ofthis study.