Corrected entry: During scenes where U-571 is being depth charged you can hear active sonar pings. The Kreigsmarine never developed active sonar and used passive sonar (basically a very sensitive listening device) instead.
Corrected entry: The German supply U-boat couldn't have sunk the S-33 with a torpedo, as neither the Type XIV nor any other class of German supply sub was equipped with torpedoes (this would have meant less storage space for cargo).
Correction: That's not entirely correct. Type XB (minelayer) had been also used as a supply boat. And these subs had 2 stern torpedo tubes. Also, Lt. Hirsch mentioned that "a resupply submarine sailed from the Lorient U-boat pens..." There was never any Type XIV boat in Loriont stationed. They were to large for the bunker systems there. But the Type XB boat U-116 was in Loriont at the time (May - September 1942).
Corrected entry: During the party at the beginning, Lieutenant Tyler addresses M. Dahlgren as "Captain." However, Dahlgren is wearing US Navy Lieutenant-Commander shoulder insignia, which is two ranks below captain. Tyler however, is wearing the right insignia. (00:10:30)
Correction: Lt. Tyler addresses Lt Cmdr Dahlgren correctly. In the Navy the commander of a vessel, regardless of his actual rank, is ALWAYS referred to as Captain. Also submarine commanders tend to be below the actual rank of captain. Lt Tyler and Lt Cmdr Dahlgren both are wearing the proper insignia for their rank.
Corrected entry: After the S-33 is torpedoed, Tyler and his men rig the U-571 for dive. Just before Wentz says "Opening midship valves; opening midship vents," someone else - I think it's the Chief - says "Opening ballast tanks." This makes no sense; the ballast tanks are the air tanks - you open them when you want to surface, not when you want to dive. (00:51:30)
Correction: Ballast tanks are opened so they can be filled with water to dive. The water is pumped out making the sub buoyant again to surface.
Correction: Actually the ballast tank vents are what are ordered to open to dive. These are deck level and as air escapes water is drawn in from the always open bottoms of the ballast tanks.
Corrected entry: After the Lieutenant Commander lectures Lieutenant Tyler aboard the SS-33 about him not being ready to become a captain, the lieutenant leaves the room. As he closes the door a double vertical bar rank insignia can be seen on each side of his collar. The double bar is captain insignia in every branch of the military and in police departments nationwide. Lieutenant Tyler should be wearing single vertical bar insignia instead.
Correction: Incorrect. This is true for all U.S. Services except the Navy & Coast Guard. In the Navy, the double-silver bars is for full lieutenant (whereas a single silver bar is Lieutenant Junior Grade) The next rank is Lieutenant Commander (gold oak leaf), followed by Commander (silver oak leaf), and Navy/Coast Guard Captain is the silver perched eagle, which is Colonel in all other branches.
Lieutenant is actually the equivalent Navy rank to an Army Captain, That's why the Lt has double bars.
Correction: Within the context of that conversation, "captain" refers not to Tyler's rank, but possible billet (assignment) as CO of a naval vessel. The "captain" might actually hold any of several ranks, depending on the size and importance of ship/boat - it doesn't have to be O-6 (Navy/CG Captain or Colonel in the other services). The next step up in rank for Lt. Tyler, LtCdr, would be consistent with typical ranks held by wartime sub commanders of the period.
Factual error: At the beginning of the movie, the German commander wants to send an emergency message with coordinates to the BdU, the German Submarine Command, to send help. The scene is subtitled in English with "To Berlin: Location 85-32." However, the command post at the time was based in Lorient, France and not in Berlin. (00:08:05)
Suggested correction: He didn't send the message to the BdU, his message was send to the OKM (OberKommando der Marine), which had its headquarters in Berlin, because it involved the enigma code (although the movie is only loosely based on historic events). These kinds of messages were always send to Berlin. This is because the OKM answered to the OKH, which in turn answered to Hitler who was of course also in Berlin. This is their concern, not that of the BdU.
Of course he does, the commander literally says to the radioman "Ruf an BdU absetzen: Position AL 85-32. Alle Maschinen ausgefallen, manövrierunfähig, erwarten Hilfe" or "Send transmission to BdU: Position AL 85-32. All engines out of service, unable to manoeuvre, we expect help." This was correct procedure, proper chain of command would always be to contact the BdU, not the OKM. Also the integrity of the enigma was probably not a concern at that time, the crew would have ample time to destroy all sensitive materials if they were in danger. The German commander's main concern was to get his sub back up and running.
Right, I couldn't understand that part before. But you are right.
Corrected entry: Almost at the end of the movie, the sub is being chased by a German destroyer. One of the destroyer cannon shots hits the stern portion of the U-Boat (where the diesel and electric motors are located). That hit should have instantly killed Tank (in the electric motors room) and maybe also Trigger (they are both working to fix the stern torpedo tube). (01:43:23)
Correction: The shot actually hits the bow of the U-Boat. The stern is pointed towards the destroyer since that tube is the only one that has a torpedo.
Correction: Not true. While never as widely used as the ASDIC active sonar by the Allies (due to lack of anti-submarine warfare/convoy duties), the Kriegsmarine developed and used their own active sonar, called S-Gerät and its later variants.