The movie tell us about the drama of sink enemy ships, by a german submarine staff. The target is sink as many possible ships and kill all person aboard. No one prisionner of war is admited. Obviously, the enemy strike-back, and the submarine tripulants suffer. Not a simple submarine, not a giant british vessel, but a history that say "we all are humans, we all suffer, we all die". We need remenber what a war can do.
I see many times and buy a copy.