High Quality Content by WIKIPEDIA articles! German submarine U-99 was a Type VIIB U-boat of the German Kriegsmarine during World War II. Her keel was laid on 31 March 1939 at the Friedrich Krupp Germaniawerft in Kiel. She was launched on 12 April 1940 under the command of Otto Kretschmer and was assigned to the 7th U-boat Flotilla based in Kiel and later in St Nazaire.