The Underwater Demolition Team, the frogmen in the film, belong to is UDT-4 (some members of the team wear utility jackets with artwork of a large number "4" and a shark on the back). The real UDT-4 in World War II saw combat in the invasions of Okinawa, Saipan, Guam, and the Philippines. Like the fictional team in the film, the UDT-4 had one of their boats hit and sunk by Japanese fire at Leyte, and left a sign on the beach at Guam to welcome the invading Marines.
This film's premiere showing was held at the U.S. Naval Amphibious Base, Little Creek, Virginia.
Although he is prominently listed in the credits, a viewer may not notice Robert Wagner at all, since he only appears in one shot saying "Aye aye, Sir". Later, in a single group shot of the flagship's crew, he has no dialogue. This was one of his earliest films and it occurred immediately after a much more noteworthy role opposite Richard Widmark in Halls of Montezuma (1951), with Twentieth Century Fox apparently building up his extra work in this film to capitalize on the super-stardom that was on the horizon. (In fact, an uncredited Jack Warden has more screen time and dialogue than 6th-billed Wagner).
Richard Widmark wears swimming trunks while the rest of the cast wears UDT shorts which navy divers, SEAL team members and EOD still wear to this day. This was probably done so Widmark's character could be distinguished from the others in the underwater scenes.
The chair used between the ships is a bosun chair.