The Mark 33 torpedo was the first passive acoustic antisurface ship/antisubmarine homing torpedo intended for the United States Navy to employ a cast aluminum shell. It featured two speeds – high and low, and was meant to be launched from submarines and aircraft.^[1]

Production of the Mark 33 was discontinued at the end of World War II, but its features were incorporated into the Mark 35 torpedo.

• American 21-inch torpedo