The studio got the U.S. Navy's permission 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 film. The cast and crew boarded in St. Thomas and filmed aboard the USS Randall (renamed the Belinda in the film). The crew shot deck and aerial photography of the Navy's maneuvers. Director Joseph Pevney hired 25 Marines as extras for the film.
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 had already been assigned, the number was not reissued.
Kerama Retto is mentioned as the destination of the 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 used as both a staging area and an emergency anchorage, exactly as shown in the movie.
This movie contains the best "beefcake" scene in the career of William Reynolds, an actor who rarely bared his chest. Here, at about age 24, he's shown shirtless, sitting up in bed while a doctor (Keith Andes) wraps a bandage around his leg.