Scenes at the marine training boot camp were filmed at the Eastney Barracks, Southsea, Hampshire, England. This facility is now the British Royal Marines Museum.
According to an article in 'The New York Times', production company Warwick Films considered shooting this movie in the CinemaScope format. If this had been the case, this would have been the first English film to do so.
During the evasion exercise, a train is shown leaving a station with a British Railways emblem on the side of the locomotive. The film takes place during WW2 (1939-1945), but British Railways did not come into existence until 1947-1948 when the railways were nationalized.
During the initiative test while the marines are making their way back to base, they cross a railway bridge as an electric train pulls into the station but when they board the train and it pulls out we hear the sound of a steam locomotive.
When the German crew are loading the depth charges, they load the only charge into (what becomes) the top muzzle when the launcher is rotated. However, when the officer gives the order to fire, the flash appears from the lower muzzle.
Major Stringer: All right, Thompson, let's clear the air a little. Ever since I came here, you've been giving me a hard time. Now just what the hell has been eating you?