Das Boot is a World War II film directed by Wolfgang Petersen. Starring Jürgen Prochnow, Herbert Grönemeyer, and Klaus Wennemann, the film documents a U-boat patrol. It is one of the most well-known German films and initiated the genre of submarine films.
The film begins in October 1941 and revolves around Lt. Werner, a German war correspondent assigned to document a patrol of U-96. He joins its Captain and Chief Engineer (LI) for drinks at the French cabaret Bar Royal, where U-boat officers drink before going on patrol. On the way, they are intercepted by U-96 sailors, who piss on their car. At the bar, Werner meets the 2WO (Second Watch Officer) and the Captain receives a final report on the sub from his 1WO (First Watch Officer), who was also pissed on by the crew. Another captain, Phillip Thomsen, celebrates his new Ritterkreuz by drunkenly mocking Hitler briefly. The night gets extremely chaotic and Werner retreats to the bathroom.
The next morning, the Captain, the LI, and Werner board the U-96 at the La Rochelle U-boat pens. They set sail amid cheering crowds and a band playing "Muss I Denn". As the day progresses, Werner is given a tour of the boat and takes lots of pictures; the Captain advises him to take more pictures when the crew returns (as they will have grown beards and it would not shame the British to see how young U-boat crewmen really are). The boat conducts its first crash dive (or "alarm"), only to be attack by a British fighter right after surfacing. Werner is able to make friends with Cadet Ullmann, who worries about the safety of his French fiancée. As the days pass, Werner learns the tediousness of living with forty people in a cramped space. With all enemy convoys and U-boats too far away, they is nothing for the crew to do but wait.
Eventually, the crew learns that U-32 has sighted a British convoy not too far away. Arriving at the grid coordinates, a thick fog reduces visibility to zero, so they dive to check the hydrophones. Hearing a depth charge attack, they resurface and sight a destroyer. The Captain decides to attack it, but as they prepare to fire, the destroyer sights them and nearly rams the U-96. The boat is shaken as the ship drops depth charges. Running the propellers on low RPMs, the submarine is able to sneak away and they resurface safely a few hours later.
- Jürgen Prochnow as Captain (Kapitänleutnant / Kaleu / Der Alte): A battle-hardened sea veteran, in his thirties. The surrogate father to his mostly young crewmen, who all look up to him. Despite being openly anti-Nazi, he is engaged to a "Nazi girl" (a widow of a Luftwaffe pilot). Prochnow later became one of the few German actors to establish themselves in Hollywood.
- Herbert Grönemeyer as Lieutenant (Leutnant) Werner, War Correspondent: The somewhat naive, but honest main narrator. He wears a seaman's jumper for much of the voyage. Werner is repeatedly mocked for his lack of sailing experience, but his help proves crucial in repairing the engines when the boat is trapped at Gibraltar. Grönemeyer later became one of the most popular German singers.
- Klaus Wennemann as Chief Engineer (Leitender Ingenieur or LI): A quiet and well-respected man. At age 27, the oldest crew member besides the Captain. Tormented by the uncertain fate of his family, especially after hearing about an Allied air raid on Cologne. The second most important crewman, as he oversees diving operations and makes sure the systems are running correctly. Because of the German pronunciation of "i" as "e", his title is pronounced like "ellie". Wennemann later became lead in a successful German detective series, Der Fahnder (the Investigator) before his death in 2000 from lung cancer.
- Hubertus Bengsch as 1st Lieutenant/ 1st Watch Officer (IWO): A stiff man, a by-the-book officer, an ardent Nazi and a staunch believer in the Wehrmacht victories. He has a condescending attitude and is the only crewman who makes the effort to maintain his proper uniform (the other crewmen immediately begin wearing more comfortable attire after the boat leaves port). His fiancée died in British carpet bombing. Raised in some wealth in Mexico by his stepparents. He spends his days writing his thoughts on military training and leadership for the High Command. Bengsch later became a successful dubbing artist, providing (amongst others) the German voice of Richard Gere.
- Martin Semmelrogge as 1st Lieutenant/ 2nd Watch Officer (IIWO): A vulgar, comedic officer, who hides a vulnerable side behind his macho image. He explains much of the submarine operations to Werner. One of his duties is to decode messages from base, using the Enigma code machine. The film started Semmelrogge's successful German film career.
- Bernd Tauber as Chief Helmsman (Obersteuermann) Kriechbaum: The navigator and IIIWO (3rd Watch Officer). He gets wounded in the airplane attack at Gibraltar. Kriechbaum has four sons, with another on the way. Following the film, Tauber became a successful actor; one of his roles was the first HIV-positive character in West Germany television on Lindenstraße.
- Erwin Leder as Chief Mechanic (Obermaschinist) Johann: The mechanic, obsessed with a near-fetish love for the U96 engine. Suffers a mental breakdown during the attack of two destroyers; he is able to redeem himself by valiantly working to stop water leaks when the boat is trapped in Gibraltar. Speaks with an Austrian accent. Leder appeared in the Gothic vampire film Underworld.
- Martin May as Cadet (Fähnrich) Ullmann: A young officer candidate who has a pregnant French fiancée (which is considered taboo by the French partisans) and worries about her safety. He is one of the few crew members with whom Werner is able to connect; Werner even offers to deliver Ullman's love letters when it seems the former will be leaving the submarine.
- Heinz Hoenig as Petty Officer (Maat) Hinrich: The radioman, sonar controller and ship's combat medic. He is in many ways the third most important crewman, since he gauges speed and direction of their targets and enemy destroyers. Hinrich is one of the few officers that the Captain is able to relate to. Hoenig later became one of the most sought-after character faces in German films.
- Uwe Ochsenknecht as Chief Bosun (Bootsmann) Lumprecht: The severe chief who shows Werner around the U-96. He supervises the firing and reloading of the torpedo tubes. The film started Ochsenknecht's successful German film career.
- Claude-Oliver Rudolph as Ario: The burly mechanic who tells that Dufte is getting married and throws around pictures of Dufte's fiancée in order to laugh at them both.
- Jan Fedder as Petty Officer (Maat) Pilgrim: Another sailor (watch officer and diving planes operator), gets almost swept off the submarine, breaks several ribs and is hospitalised for a while. Speaks with a Hamburg accent. Fedder later became lead in a successful light-hearted German police series, Großstadtrevier.
- Ralf Richter as Petty Officer (Maat) Frenssen: Pilgrim's best friend. Pilgrim and Frenssen love to trade dirty jokes.
- Joachim Bernhard as Theologian (Bibelforscher): A religious sailor who is constantly reading the Bible. He is punched by Frenssen when the submarine is trapped at the bottom of the Straits of Gibraltar for praying rather than repairing the boat. Bernhard is the brother of Semmelrogge and has not acted since the early 1990s.
- Oliver Stritzel as Schwalle: The blond sailor who speaks with a Berlin accent.
- Jean-Claude Hoffmann as "Little" Benjamin: A red haired sailor who serves as a diving planes operator and watch officer.
- Lutz Schnell as Dufte: The sailor who gets jeered at because he is getting married and for a possible false airplane sighting. Schnell's later career was dominated by voice-over work.
- Otto Sander as Kapitänleutnant Phillip Thomsen: Another U-Boat commander, an alcoholic and shell shocked member of "The Old Guard". When he is introduced, he is extremely drunk and briefly mocks Adolf Hitler. Sometime after U-96 departs, Thomsen is deployed once again and the two submarines meet randomly in the middle of the Atlantic Ocean. After failing to make contact later, the Captain is forced to report to HQ that Thomsen is missing. Otto Sander is one of Germany's most prolific character actors, including the angel Cassiel in Wings of Desire alongside Bruno Ganz.
- Günter Lamprecht as Captain of the Weser: An arrogant Nazi officer aboard the resupply ship Weser. He mistakes the 1WO for the Captain as they enter the ship's elegant dining room. Lamprecht went on to have a successful career in German cinema and television.
- Sky du Mont (uncredited) as Officer Aboard the Weser: An officer aboard the Weser whom the 2WO amuses with a comical demonstration of depth charging. du Mont narrates the German dub of Thomas and Friends and appeared in the film Night Crossing, about an infamous escape from East Germany.
The film features characters who speak German with a regional dialect. Director Wolfgang Petersen states in his DVD audio commentary that young men from throughout Germany and Austria were recruited for the film. He wanted faces and accents that would accurately reflect the diversity of the Third Reich circa 1941. All of the main actors speak fluent English as well as German; when the film was dubbed into English, each actor recorded his own part (with the exception of Martin Semmelrogge, who only dubbed his own role in the Director's Cut). The German version is actually dubbed as well; the film itself was shot "silent", since in any case the dialogue spoken on-set would have been drowned out by the gyroscopes in the special camera developed for filming. While several actors went on to even greater success, Wolfgang Petersen established himself as a long-standing fixture as a Hollywood director and producer.