German submarine U-102 (1940)

German submarine U-102 was a Type VIIB submarine of Nazi Germany's Kriegsmarine during World War II.

The U-boat was laid down on 22 May 1939 at the Friedrich Krupp Germaniawerft shipyard at Kiel as yard number 596, launched on 21 March 1940 and commissioned on 27 April under the command of Kapitänleutnant Harro von Klot-Heydenfeldt to serve with the 7th U-boat Flotilla from 27 April 1940 to 1 June for crew training and operationally until she was sunk on 1 July. She sank one Allied ship, claiming.

Design
German Type VIIB submarines were preceded by the shorter Type VIIA submarines. U-102 had a displacement of 753 t when at the surface and 857 t while submerged. She had a total length of 66.50 m, a pressure hull length of 48.80 m, a beam of 6.20 m, a height of 9.50 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two AEG GU 460/8-276 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.9 kn and a maximum submerged speed of 8 kn. When submerged, the boat could operate for 90 nmi at 4 kn; when surfaced, she could travel 8700 nmi at 10 kn. U-102 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and one 2 cm anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
U-102's first and only patrol began on 22 June 1940. Having sunk the Clearton about 180 nmi west of Ushant (often known as Ouessant, an island in northwest France) on 1 July, she was herself sunk on the same day as the latter ship by depth charges from a British destroyer, HMS Vansittart (D64).

43 men died with the submarine; there were no survivors.

After the U-boat's sinking, Vansittart rescued the 26 survivors from Clearton.

Previously Recorded Fate
U-102 was originally believed to have been sunk in the Bay of Biscay due to unknown causes on or after 30 June 1940.