Seisho Maru (Japanese: 盛祥丸, Seishō Maru ) was a cargo ship for Mitsui Bussan Kaisho in military service that was sunk by an American submarine during World War II. The ship had been built as SS West Caruth, a cargo ship for the United States Shipping Board (USSB) shortly after the end of World War I. Shortly after completion, the ship was inspected by the United States Navy for possible use as USS West Caruth (ID-2850) but was neither taken into the Navy nor ever commissioned under that name. Before being sold to Japanese owners in 1928, she was also known as SS Exmoor and SS Antonio Tripcovich.