Bliss-Leavitt Mark 4 torpedo
The Bliss-Leavitt Mark 4 torpedo was a Bliss-Leavitt torpedo developed and produced by the E. W. Bliss Company in 1908. It was the first American-built torpedo specifically designed to be launched from a submarine. About 100 Mark 4s were purchased for experimental purposes by the United States Navy, which led to design improvements to the gyro and the reducing valve. The Mark 4 and all other torpedoes designed before the Bliss-Leavitt Mark 7 torpedo, were considered obsolete and withdrawn from service in 1922.
