Revealing mistake: In one scene just before the attack on a big Hunter the young captain (Jürgen Prochnow) is sitting with his charts. Beside him he has got a glass of beer standing. The sub lurches heavily right and left in the hard weather, but the surface of the liquid stays the same.
Das Boot (1981)
1 revealing mistake
Directed by: Wolfgang Petersen
Starring: Jurgen Prochnow, Herbert Gronemeyer, Hubertus Bengsch, Klaus Wennemann
Continuity mistake: At the end of the first attack by the destroyer - where she misses the U-boat and throws her bombs further away - the boatswain makes 22, then 23 strokes on the slate of the Control Centre,thus counting the number of depth charges used against the boat. A few seconds later, in a shot from another angle, with the slate in full view, we see only 22 strokes. (01:03:30)
Captain: April fool. Practice makes perfect.
Trivia: The full sized mock up of the U boat was rented by Steven Spielberg for use in the first Indiana Jone's film.
Question: I know practically nothing about submarines, so this seemed a bit strange to me. When there's that huge storm, why do they keep staying at the surface, only going down for an hour at a time?
Answer: Because that's what the U-boat was designed to do. Unlike modern nuclear boats, they didn't have the capacity to stay submerged for long periods - basically just as long as the air lasted; there wasn't atmosphere control equipment. They would 'snorkel' near the surface, recharge the batteries with the diesel engines, and then dive for a few hours at most before having to come back up and repeat the process.
Answer: U-boats also travelled much faster on the surface...about 18 knots, vs only 8 knots or so beneath the surface.