If being in the middle of the ocean, in the middle of a war, under water, in overheated cramped quarters floats your boat - definitely check out the USS Pampanito!
This heroic submarine (sunk:6, damaged:4) offers a great look into WW2 technology. Officially run by the Maritime Museum, the Pampanito is 3 blocks away and has separate admission.
Address: Pier 45, SF, CA
Website: http://www.maritime.org/pamphome.htm
Wikipedia: http://en.wikipedia.org/wiki/USS_Pampanito_(SS-383)