I was very disappointed in this film. The enigma codes were in reality recovered by the British sailors in surface ships and I am not aware of any heroic American mission to recover them. For a start the construction of American heroes on this theme seemed wrong. Then the plot began to drag as all the old submarine war movie cliches were rerun - the tension between CO and XO, the destroyer-submarine combat, the depth charges, the leaking pipes and the frightened faces of cocooned men hundreds of feet below the surface. The representation of the technology also wrankled me. The rate at which charges are dropped by destroyers would make the close succession of explosions near the sub impossible. Moreover, the closeness of those explosions at 200m depth would definitely have imploded the hull. Generally, a load of garbage.
