also received a preferential promotion to Korvettenkapitän (corvette captain) and Dönitz presented him an honorary dagger of the Kriegsmarine with diamonds. Ashore Command of U-552 was passed on to Kapitänleutnant Klaus Popp. Topp officially remained with the 7th U-boat Flotilla until 4 November, when he was appointed chief of the 27th U-boat Flotilla, a training flotilla based in Gotenhafen (now Gdynia, Poland). In August 1944, Topp was appointed head of the department charged with introducing the Type XXI submarines into service, the first submarines designed to operate primarily submerged. In this position, he was promoted to Fregattenkapitän (frigate captain) on 1 December 1944. On 23 March 1945, he was appointed commander of in the 4th U-boat Flotilla, and commander of in the 11th U-boat Flotilla on 26 April. On 20 May 1945, Topp was taken prisoner of war in Kragerø, Norway. He was released on 17 August 1945. Topp's boat, U-2513, was tested by the US Navy. American reports concluded at 12 knots submerged speed, she is quieter than our best fleet submarines at six....up to 10 knots she is extremely quiet." The same report concluded at least seven ships were required to carry out a search for the XXI submarine. Later life and Bundesmarine On 4 June 1946, he started at the Technical University of Hannover, studying architecture, and graduated in 1950 with a degree in engineering. He also served as technical advisor for the 1957 film Sharks and Little Fish. On 3 March 1958, Topp joined West Germany's navy, at the time named the Bundesmarine (Federal Navy), holding the rank of Fregattenkapitän. His first assignment was with the Führungsstab der Marine (navy staff). On 16 August 1958, he served with the NATO Military Committee in Washington, DC, initially as a naval speaker, later as the chief-of-staff of the German delegation in Washington. During this assignment, he was promoted to Kapitän zur See (captain at sea/captain) on 1 November 1959. On 1 January 1962, Topp was transferred to the position of commander of the Bundesmarines Amphibische Streitkräfte ("amphibious forces"), a position he held until 30 September 1963. In parallel, on 1 November 1962, he was made acting commander of U-boats, serving in this capacity until 1 December 1962. Topp was then appointed chief-of-staff of the Flottenkommando (Fleet Command) on 1 October 1963. On 1 July 1965, he headed the sub command department with Führungsstab der Marine in the Federal