German submarine U-40 was a Type IXA U-boat of Nazi Germany's Kriegsmarine that operated during World War II.
U-40 was built in Bremen by DeSchiMAG AG Weser as yard number 945. She was launched in November 1938 and commissioned in February 1939.
U-40 conducted two war patrols during her career. Both of which were part of the 6th U-boat Flotilla. During her short time in the war, she sank no ships.
U-40 was sunk on 13 October 1939 by a mine in the English Channel.
German Type IXA submarine
U-40 was ordered by the Kriegsmarine on 29 July 1936 (as part of Plan Z and in violation of the Treaty of Versailles). Her kneel was laid down on 1 July 1937. U-40 was launched on 9 November 1938 and commissioned on 11 February 1939 under the command of Kapitänleutnant Werner von Schmidt.
As one of the eight original German Type IX submarines, later designated IXA, U-40 had a displacement of when at the surface and while submerged. The U-boat 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 MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 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-40 was fitted with six torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one SK C/32 naval gun, 180 rounds, and a SK C/30 as well as a C/30 anti-aircraft gun. The boat had a complement of forty-eight.
After being commissioned and deployed, U-40 was stationed in the German port city of Wilhelmshaven, which to be her home for the rest of her fairly short career.
U-40 left Wilhelmshaven on 19 August 1939, before World War II began, for her first patrol.