This film is purely for entertainment and not of any historical background. Still, navy/sea warfare buffs will enjoy the story of the pursuit by a British destroyer of a German merchant ship across several oceans. The cast is so-so but with the "Duke" (John Wayne) in the lead role the story manages to limp along with some degree of success. The "destroyer" used in the film is in fact HMCS New Glasgow, a frigate then in service with the Royal Canadian Navy. I saw the movie shortly after it's release in 1955 while in my mid-teens; a number of years later I served on New Glasgow and recalled the part played by the ship and crew in the film. Shows how Hollywood will use any "prop" available to fill in scenes. The crew never did get any extra pay for their appearance (nor did the ship)but at least they have the satisfaction of knowing the true identity of the "destroyer." Despite all the above the film is good viewing and will be of interest to many.