USS Alabama (BB-60) is a retired battleship. She was the fourth and final member of the South Dakota class of fast battleships built for the United States Navy in the 1940s. The first American battleships designed after the Washington treaty system began to break down in the mid-1930s, they took advantage of an escalator clause that allowed increasing the main battery to 16-inch (406 mm) guns, but Congressional refusal to authorize larger battleships kept their displacement close to the Washington limit of 35,000 long tons (36,000 t). A requirement to be armored against the same caliber of guns as they carried, combined with the displacement restriction, resulted in cramped ships. Overcrowding was exacerbated by wartime modifications that considerably strengthened their anti-aircraft batteries and significantly increased their crews. wiki