Factual errors: The submarine "Copperfin" is essentially a "Gato" class boat, yet through the evolution of that class the superstructure changed as well as the armament. In the film you see everything from a 20MM gun to a 40MM as well as numerous .30 and .50cal machine guns, not to mention a 3" deck gun. The footage of the sub changes numerous times during the film, including the armament as well as the superstructure, obviously due to the extensive use of stock footage.
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