The Mark 14 torpedo was introduced into the navy in 1929. It was 20.5 feet long, 21 inches in diameter, weighed 3300 pounds, had a range of 5500 to 9000 yards, and used steam turbine propulsion. Its warhead originally contained 507 pounds of TNT with a contact exploder. During the next 60 years, this class underwent 6 modifications. The warheads were later upgraded with 668 pounds of TPX and 600 pounds of TPS respectively, while maintaining the contact exploder. It was taken out of service in 1959, reinstated in 1969, and withdrawn from service in the late 1970’s. During World War II, U.S. Navy submarines sank more shipping tonnage with the Mk 14 Torpedo than from all other sources combined.