Ships used in the film: HMS Sheffield as HMS Ajax, INS Delhi (HMS Achilles 1933-41, HMNZS Achilles 1941-46) as HMS Achilles, HMS Cumberland as HMS Cumberland, Heavy Cruiser USS Salem as the German pocket battleship Admiral Graf Spee. Light cruiser HMS Jamaica played the part of heavy cruiser HMS Exeter.
The Admiral Graf Spee was portrayed in the film by the USS Salem, despite the latter having the wrong number of main turrets. Of course, they weren't able to scuttle the real Salem so that was the only real occasion that models were used extensively.
The original English version of the film omits the tragic final act of the story. A few days after scuttling his own ship, German Captain Hans Langsdorff committed suicide in a hotel room in Buenos Aires. He was dressed in full uniform and wrapped in the battleflag of his sunken vessel. In the German dubbed version, the final voice-over was changed to explain what happened to Langsdorff.
There was heavy speculation than German Captain Hans Langsdorff committed suicide rather than face the humiliation of losing his ship. There was even more speculation that he did it because he feared what Hitler would do to him if he returned to Germany. At the time the Graf Spee was the pride of the German Navy and scuttling her would have been regarded as treason.
Location filming started on 13 December 1955, the 16th anniversary of the battle. The River Plate Association in Auckland sent a good-luck message to the crew. "Congratulations on choice of day. Hope your shooting will be as successful as ours!"
Attention to detail was particularly important to the producers, so all the naval procedures depicted in the film are completely accurate. The scene where Harwood meets with his captains on board the Ajax, however, was a fictitious one, created in order to explain the situation to the audience.
John Schlesinger, then an actor, is listed in the credits as Prisoner on the Graf Spee. In actual fact the future director played a German officer, the young Lieutenant who escorts Captain Dove to the ship after the Africa Shell is sunk and introduces him to Langsdorff.
According to the book 'The Golden Gong - Fifty years of the Rank Organisation, its films and its stars' by Quentin Falk, this movie was " . . . the last of the Archers true collaborations" with a return to the Rank Company during the mid 1950s after Michael Powell and Emeric Pressburger had left after The Red Shoes (1948).