The studio received permission from the US Navy to join 200 ships and 10,000 men in the Virgin Islands to film a three-day assault on the Puerto Rican island of Vieques. Some of the footage was included in this movie. The cast and crew boarded in St. Thomas and filmed aboard the USS Randall (renamed the "Belinda" in this movie). The crew shot deck and aerial photography of the Navy's maneuvers. Director Joseph Pevney hired 25 Marines as extras.
Kerama Retto is mentioned as the destination of USS Belinda after she is seriously damaged by a kamikaze. This island, about a dozen miles southwest of Okinawa, was taken by the 77th Infantry Division at the start of the invasion, and was used as a staging area and an emergency anchorage, exactly as shown in this movie.
The name "Belinda" is a fabrication. No ship ever sailed with the hull number of APA-22. The USS Joseph Hewes (AP-50) was designated for reclassification as APA-22 in early 1943, but she was lost in November of 1942 before the change occurred. As the numerical sequence of attack transport hull numbers already had been assigned, the number was not reissued. AP-22 USS Mount Vernon was aquired by the U.S. Navy in June 1941 and converted from the Passenger Liner S.S. Washington and served from the until 1946