31st U-boat Flotilla
31st U-boat Flotilla ("31. Unterseebootsflottille") was a training flotilla (""Ausbildungsflottille"") of Nazi Germany's "Kriegsmarine" during World War II. The flotilla was formed in Hamburg in September 1943 under the command of "Kapitän zur See" Bruno Mahn. Later based at Wilhelmshaven, and then Wesermünde, it was commanded by Carl Emmermann for the final month of the war. It was disbanded in May 1945 when Germany surrendered. Assigned U-boats. 156 U-boats were assigned to this flotilla during its service.