Name U-644 Yard number 144 Commissioned 15 October 1942 Launched 20 August 1942 Draft 4.74 m Builder Blohm + Voss | Ordered 20 January 1941 Laid down 1 December 1941 Construction started 1 December 1941 Length 67 m Beam 6.18 m | |
Fate Sunk by British submarine in position | ||
German submarine U-644 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 1 December 1941 at the Blohm & Voss yard at Hamburg, launched on 20 August 1942, and commissioned on 15 October 1942 under the command of Oberleutnant zur See Kurt Jensen.
Contents
Attached to 5th U-boat Flotilla based at Kiel, U-644 completed her training period on 31 March 1943 and was assigned to front-line service.
Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-644 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged. She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph). When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-644 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and an anti-aircraft gun. The boat had a complement of between forty-four and sixty.
Service history
In April 1943, U-644 was on patrol between the Shetlands and Jan Mayen. British signals intelligence had pinpointed the U-boat's position and HMS Tuna was dispatched to hunt down U-644. On 7 April, the Tuna detected the U-boat only 500 metres (550 yd) away and fired a spread of five torpedoes. Two torpedoes hit U-644, which sank with all 45 crew members on board, there were no survivors.