Simone Strasser arrives from Alsace to work at the Police H.Q. In the meantime he gives evidence at the court-martial of a submariner accused of cowardice in the face of the enemy and attends the execution, whereupon he performs a mercy killing. In La Rochelle, U-612 is being readied for its maiden voyage under the inexperienced Captain Klaus Hoffmann. U-113 is then barraged with depth charges by an American destroyer and sinks with the loss of all hands on board. Captain Wrangel goes overboard whilst the U-boat is forced to dive. U-113 is attacked by an Allied plane in the Atlantic Ocean. Pierre Kiwitt as Korvettenkapitän Bobby Schulz ("King Kong").Ernst Stötzner as older Wilhelm Hoffmann.Ulrich Matthes as Kapitän zur See a.D.Michael McElhatton as Deputy Inspector Thomas O'Leary.Marvin Linke as Funkgast Peter Kraushaar.Ben Münchow as Dieselmaschinist Lutz Rizenhoff.Klaus Steinbacher as Obermechanikermaat Josef Wolf.Julius Feldmeier as Obersteuermann Eugen Strelitz.Luise Wolfram as Hannie Hoffmann Lessing.Florian Panzner as Fregattenkapitän Albrecht Lessing.Martin Schnippa as Maschinenmaat Dieter Heizer.Joseph Konrad Bundschuh as Leutnant zur See Julius Fischer ( 2WO).Samuel Valentine as Lieutenant Commander David Mercer, HMS Perseverance.Ray Stevenson as Commander Jack Swinburne, HMS Perseverance.Stefan Konarske as Korvettenkapitän Ulrich Wrangel ("Der Alte").Pit Bukowski as Obermaschinenmaat Pips Lüders.Leon Lukas Blaschke as Mechanikergast Thorsten Hecker.Rafael Gareisen as Mechanikerobergefreiter Max von Haber.Philip Birnstiel as Leutnant zur See Benno Schiller ( 2WO).Franz Dinda as Oberleutnant (Ing.) Robert Ehrenberg ( LI).Thierry Frémont as Inspector Pierre Duval.Joachim Foerster as Elektromaschinenmaat Ralf Grothe.Tom Wlaschiha as Kriminalrat Hagen Forster.August Wittgenstein as Oberleutnant zur See Karl Tennstedt ( 1WO).Clemens Schick as Korvettenkapitän Johannes von Reinhartz.Rainer Bock as Fregattenkapitän Heinrich Gluck.Leonard Scheicher as Oberfunkmaat Frank Strasser.Robert Stadlober as Oberfähnrich (Ing.) Hinrich Laudrup ("Smut").Rick Okon as Kapitänleutnant Klaus Hoffmann ("Kaleun").A fourth season (6 episodes) has been ordered, with filming set to begin in June 2022. A source from broadcast network Sky cites sensitivities to the ongoing conflict in Ukraine as the reason for the five week delay of the Season 3 release. Season 3 was originally slated for 9 April 2022 but was pushed back to debut in Europe on 14 May. The storyline is split into two narratives, one based on land around the French Resistance, the other set around German U-boat U-612 and its crew. As the original film's plot ends in December 1941, the series' setting takes place nine months later, in 1942.
Like the film, the series is based on Lothar-Günther Buchheim's 1973 book Das Boot, but with additions from Buchheim's 1995 sequel Die Festung. Das Boot is a German television series produced for Sky One and a sequel to Das Boot (1981).