8After averaging the completion of less than two submarines a year in the 1930s, the Portsmouth Navy Yard completed an astonishing thirty-two submarines in 1944 including the simultaneous launching of three submarines. The yard built seventy-nine submarines between 1941 and 1945, a fleet that collectively represented thirty-seven percent of the United States submarines built during the war and sank over one third of the Japanese shipping sunk by United States submarines. 32 in '44 analyzes the factors behind the yard's record setting submarine production that made such a significant contribution to the winning of the war.