Jan 12, 2013 · METAL HAS BEEN USED to build ships for about 160 years, and very large metal yachts were being built as early as the late 19th century. In 1895, for example, Nat Herreshoff designed and constructed a radical 123-footposite metal sloop, Defender, to defend the America’s Cup. She was built of aluminum, bronze, and steel and within six years ...Dec 17, 2005 · Being able to weld it is the real issue on small boats. Riveted hulls can be as thin as 1mm. 3mm makes a good easily, inexpensively, weldable, durable hull, 4mm and you can go ramming other boats.. well not quite.. JDF. '"Forward, the Light Brigade!"'. -Alfred Lord Tennyson.5083 Aluminum alloy 5083 ismonly used by the US Navy. It’s stronger than 5052, yet it’s still formable and easily welded. This aluminum alloy is widely used in chemical and marine environments where corrosion resistance is crucial and can also withstand extremely cold temperatures without bing brittle.So using the example, 10GA (.1345″) bottom plating in the steel boat, and applying our rule-of-thumb, results in a nominal 3/16″ (.190″) plating thickness in aluminum, or just over 40% thicker. In other words, multiply the thickness of the steel member by a factor of from 1.3 to 1.5 to arrive at the thickness required in aluminum.