'Hollywood Reporter' production reports of cast and crew state that Charley Grapewin was part of this movie's cast, but he is not seen in the final film.
'The Hollywood Reporter' reported that the United States Navy would be having a recruitment station in the lobby of Grauman's Chinese Theatre for the Hollywood Premiere of this picture on 27 May 1942, planning to have it open for the whole of the movie's season at the theater.
Tyrone Power's picture credit reads "Tyrone Power U.S.M.C.R.", the latter letters after his name standing for United States Marine Corps Reserves.
Norman Nesbitt was scheduled to narrate a "special trailer" for this movie according to 'The Hollywood Reporter'.
According to 'Hollywood Reporter', William Perlberg was originally going to be a producer on this picture. Milton Sperling was then assigned producing duties but on 10 September 1942 he joined the Marine Corps. He was replaced by Lee S. Marcus, who joined the movie while it was in production.
Background shots for this movie were filmed at the United States Navy's Naval Submarine Base New London situated at New London, Conneticut.
Final film for Tyrone Power prior to entering military service as a private. He is credited in the film as as Tyrone Power U.S.M.C.R. On 1 October 1942, Power was allowed to defer the start of his military duties in order to complete production on this movie which did not finish shooting until mid-November 1942. Power did not star in another movie until 1946 when he appeared in The Razor's Edge. At the time of Power's death in 1958, he was a Major in the United States Marine Corps Reserves.
Neither the later pictures Crash Dive nor its sequel Counter Measures (aka Crash Dive 2) are remakes of this film. They merely all share being submarine movies and being part of the sub-movie genre with a submarine term title.
The film utilizes an oft-used storyline of the war movie genre which has two soldiers in love with the same girl.
The PT boats seen at the beginning (and for a brief moment, at the end) of the film are Elco 77-foot PTs, the type of boat that saw intense combat against the Japanese Navy's "Tokyo Express" in the Guadalcanal area early in World War II. The wartime second-series Elco 77-footers, which were the same type as PT 59, John F. Kennedy's second command after PT 109 was rammed and sunk, are seldom seen on film, and hardly ever in color.
The US Navy provided naval equipment and allowed access to their fleet of submarines and also supplied service personnel.
This movie had two working titles: 'Submarine School' and 'SS 111'.
This movie represents one of a select group of a few World War II submarine movies which have won the one single Academy Award in a technical category, that's just only the one Oscar in either special effects or sound editing. These movies include Crash Dive; The Enemy Below; Torpedo Run and U-571. The non-WW II sub-movie, The Hunt for Red October also won just the one Oscar as did the WW 2 part sub-movie 49th Parallel, but for Best Original Story.
This movie's closing credits feature an advertisement for the World War II USA war effort at the end of the credits roll. It states: "For Victory - U.S. War Bonds and Stamps - Buy yours in this theatre."
This movie's opening prologue states: "The cooperation and assistance of the officers and men of the U.S. Navy submarine base, New London, Connecticut, is gratefully acknowledged."