In my opinion, quite simply the best submarine movie ever made. The camerawork is Fantastic, melding the fictional crew and audience together in a way that is almost uncanny. Every experience, the cramped quarters, the fear, and excitement is directly transmitted to the audience.
At one point, a torpedo sinks a ship, and the American audience Cheers---followed by an uneasy silence as the realization that they had sunk an Allied ship sinks in.I saw the movie 3 times, and each time the same thing happened.
Not for kids, the faint of heart, or the claustrophobic. Get the version in German. The subtitles aren't a bother, and the translation in the dubbing waters down the emotion and meaning.