Barquist Paul Young as Leading Seaman Quentin William Dysart as Lt. Gogan R.N.R. John Kelland as Sub. Lt. Willis R.N.V.R. Kenneth Farrington as C.P.O. Boker Knowles Keith Alexander as Sub. Lt. X-3 Carl Rigg as C.P.O. Kennedy Steve Kirby as Leading Seaman X-2 Nicholas Tate as Leading Seaman X-1 George Pravda as Captain Erlich Rupert Davies as Vice-Admiral Redmayne (uncredited) Production The film was one of a series of war movies made by Walter Mirisch in Britain with an imported American star in the lead. See also Above Us the Waves is a similar film about the true-life submarine attacks on the Tirpitz. Operation Source details the use of X class submarines against German battleships in World War II. Tirpitz the real-life German battleship attacked by British X class submarines during World War II in a Norwegian fjord. References External links Submarine X-1 at Yahoo! Movies 1968 films British war films 1960s English-language films Films set in 1943 Royal Navy in World War II films Seafaring films based on actual events World War II films based on actual events World War II submarine films Films scored by Ron Goodwin Films directed by William Graham (director) 1960s British films