ssc-452 aluminum structure design and fabrication guide ship

Aluminum Marine Structure Guide
Maritime. Possibly, the use of aluminum for the hulls by other French yards interested
Wetherbee, who used this new technology (Friedman, 1982). However, the aluminum in these
boats evidently fared no better than it had in other applications, for aluminum was not used again
in structural applications for forty years.
In the 1930s, lightweight topside structure was becoming important for destroyers. A
welded corrosion resisting steel panel, consisting of face sheets of 0.5-mm (0.02-inch) plate, spot
welded to stiffeners separated 51 mm (2 inches) and 25 mm (1 inch) thick, was riveted to frames
which were originally corrosion resistant steel, but in later ships changed to mild steel (C&R,
1934). These CRES panels were used for DD-364 through DD-396.
In 1935, aluminum was reintroduced to deckhouse design as a replacement for brass in
the portion of the pilot house near the magnetic compass (C&R, 1935). Aluminum was used
extensively at that time for many other nonstructural purposes, including furniture and joiner
bulkheads. With the DD-409 class, designed in 1936, came the greatest use of aluminum for
exposed deckhouse structure. Plating was mixed, some of aluminum, some of mild steel, with
the framing of mild steel (C&R, 1936). This application of aluminum plate was apparently
successful, because the next class designed, the DD-423, used aluminum for plating throughout
the entire deckhouse, except where thick steel was used for fragment protection (C&R, 1938).
Insight as to the reasoning behind this change is documented in the newsletter of the
Bureau of Construction and Repair (C&R, 1936A). Aluminum was accepted, even though it
weighed more than the corrosion-resisting steel panels, because of lower cost, less likelihood of
local damage, easier repair, and better corrosion resistance. The effect of fire was considered,
but “the steel framing would ... support such weights as needed to be supported until repairs
could be made.”
The first technical bulletin of the newly formed Bureau of Ships is a summary of U.S.
Navy experience up to 1940 with riveted aluminum. Troubles were found with the early
applications that could be “traced to improper methods of design, fabrication, or upkeep” (Pyne
et al., 1940). Design problems were caused by improper alloy selection, insufficient rigidity, use
of welding, use of tap bolts, improper riveting and overheating. Severe corrosion resulted when
gasketing materials on faying surfaces were not impregnated with a suitable paint. The early
years of aluminum use evidently were not trouble-free.
Design of deckhouse structure became rather standardized with mild steel transverse
frames spaced 21 inches supporting aluminum plating that was 4.8 mm (3/16 inches) thick
everywhere except in way of gun blast, where it was 6.3 mm (1/4 inches) thick. The next major
design, the Fletcher (DD-445) class destroyers, used this configuration from the beginning of the
class in 1940. However, with the onset of World War II, all uses of aluminum except for aircraft
came under careful scrutiny because of shortages, and the use of aluminum in Navy. ships was
temporarily discontinued. The DD-445 class was thus a mixture of steel and aluminum.
With the USS Gearing (DD-692) and USS Sommer (DD-710) class destroyers, riveted
aluminum came back, being used for about half of the deckhouse sides and decks, although the
transversely framed stiffeners were welded steel. Following the war, the development of
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