German submarine U-666
German submarine U-666 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 16 September 1941 by Deutsche Werft, Hamburg as yard number 815, launched on 18 July 1942 and commissioned on 26 August 1942 under Kapitänleutnant Herbert Engel. Oberleutnant zur See Ernst Wilberg took over command on 10 December 1943. Design German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-666 had a displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two Siemens-Schuckert GU 343/38–8 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to . The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-666