German submarine U-640


German submarine U-640 was a [German German Type VIIC submarine|Type VIIC submarine|Type VIIC] U-boat built for Nazi Germany's Kriegsmarine for service during World War II.
She was laid down on 30 October 1941 by Blohm & Voss, Hamburg as yard number 616, launched on 23 July 1942 and commissioned on 17 September 1942 under Oberleutnant zur See Karl-Heinz Nagel.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-640 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 Brown, Boveri & Cie GG UB 720/8 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-640 was fitted with five torpedo tubes, fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and one twin C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history

The boat's career began with training at 5th U-boat Flotilla on 17 September 1942, followed by active service on 1 May 1943 as part of the 6th Flotilla.
In 1 patrol she sank no ships.

Wolfpacks

U-640 took part in one wolfpack, namely:
  • Iller

Fate

There are discrepancies between the fate of U-640 and, which was sunk in the same vicinity around the same time. Paul Kemp's book attributes the sinking of British freighter Aymeric to U-640, and then subsequently sunk by on the 17 May 1943, whereas UBoat.net attributes this success and fate to U-657.
Uboat.net states that U-640 was sunk on 14 May 1943 in the Atlantic Ocean in position, by depth charges from a US Catalina of VP-84. All hands were lost.