German World War II submarine
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|
| History |
|---|
 Nazi Germany |
|---|
| Name | U-644 |
| Ordered | 20 January 1941 |
| Builder | Blohm & Voss, Hamburg |
| Yard number | 620 |
| Laid down | 1 December 1941 |
| Launched | 20 August 1942 |
| Commissioned | 15 October 1942 |
| Fate | Sunk by HMS Tuna in position 69°38′N 5°40′W / 69.633°N 5.667°W / 69.633; -5.667 on 7 April 1943 |
| General characteristics |
|---|
| Class and type | Type VIIC submarine |
| Displacement |
- 769 t (757 long tons) surfaced
- 871 t (857 long tons) submerged
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| Length | |
| Beam |
- 6.20 m (20 ft 4 in) (o/a)
- 4.70 m (15 ft 5 in) (pressure hull)
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| Height | 9.60 m (31 ft 6 in) |
| Draught | 4.74 m (15 ft 7 in) |
| Installed power |
- 2,800–3,200 PS (2,100–2,400 kW; 2,800–3,200 bhp) (diesels)
- 750 PS (550 kW; 740 shp) (electric)
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| Propulsion | |
| Speed |
- 17.7 knots (32.8 km/h; 20.4 mph) surfaced
- 7.6 knots (14.1 km/h; 8.7 mph) submerged
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| Range |
- 8,500 nmi (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph) surfaced
- 80 nmi (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
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| Test depth | |
| Complement | 4 officers, 40–56 enlisted |
| Armament | |
| Service record |
| Part of: |
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| Identification codes: |
M 49 683 |
| Commanders: |
- Oblt.z.S. Kurt Jensen
- 15 October 1942 – 7 April 1943
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| Operations: |
- 1 patrol:
- 18 March – 7 April 1943
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| Victories: |
None |
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.
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 one twin 2 cm (0.79 in) C/30 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 Shetland 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 British submarine 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.
