In the opening scene, the boy in the raft says that he can hear airplanes, which turn out to be PT boats. Many of the WWII PT boats were powered by airplane engines.
The U.S. Navy provided naval equipment and allowed access to their fleet of submarines and also supplied service personnel.
Background shots for this movie were filmed at the United States Navy's Naval Submarine Base situated at New London, Connecticut.
'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 1943, planning to have it open for the whole of the movie's season at the theater.