Development began in 1979. Several American directors were considered three years earlier before the film was shelved. During production, Heinrich Lehmann-Willenbrock, the captain of the real "U-96" during Buchheim‘s 1941 patrol and one of Germany's top U-boat "tonnage aces" during the war, and Hans-Joachim Krug, former first officer on , served as consultants. One of Petersen's goals was to guide the audience through "a journey to the edge of the mind" (the film's German tagline ), showing "what war is all about".