| History | |
|---|---|
| Name | U-731 |
| Ordered | 21 November 1940 |
| Builder | Schichau-Werke,Danzig |
| Yard number | 1522 |
| Laid down | 1 October 1941 |
| Launched | 25 July 1942 |
| Commissioned | 3 October 1942 |
| Fate | Sunk on 15 May 1944 |
| General characteristics | |
| Class & type | Type VIICsubmarine |
| Displacement | |
| Length |
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| Beam |
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| Height | 9.60 m (31 ft 6 in) |
| Draught | 4.74 m (15 ft 7 in) |
| Installed power |
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| Propulsion |
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| Speed |
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| Range |
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| Test depth |
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| Complement | 4 officers, 40–56 enlisted |
| Armament |
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| Service record | |
| Part of: |
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| Identification codes: | M 50 791 |
| Commanders: |
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| Operations: |
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| Victories: | None |
German submarineU-731 was aType VIICU-boat ofNazi Germany'sKriegsmarine duringWorld War II. The submarine waslaid down on 1 October 1941 at theSchichau-Werke yard atDanzig,launched on 25 July 1942, andcommissioned on 3 October 1942 under the command ofOberleutnant zur See Werner Techand.
Attached to8th U-boat Flotilla based atKiel,U-731 completed her training period on 30 April 1943 and was assigned to front-line service.
German Type VIIC submarines were preceded by the shorterType VIIB submarines.U-731 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.[1] She had a total length of 67.10 m (220 ft 2 in), apressure hull length of 50.50 m (165 ft 8 in), abeam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and adraught of 4.74 m (15 ft 7 in). The submarine was powered by twoGermaniawerft F46 four-stroke, six-cylindersuperchargeddiesel 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, twoAEG GU 460/8–27double-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).[1]
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).[1] 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-731 was fitted with five 53.3 cm (21 in)torpedo tubes (four fitted at the bow and one at the stern), fourteentorpedoes, one8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and two twin2 cm (0.79 in) C/30anti-aircraft guns. The boat had acomplement of between forty-four and sixty.[1]
On the fourth and final war patrol,U-731 was detected on 15 May 1944 by twoCatalinas, P-14 and P-1, ofVP-63 off Tangiers, when the U-boat tried to force the Strait of Gibraltar. Two British patrol craft,HMS Kilmarnock andHMS Blackfly, received reports of the U-boat and attacked with hedgehogs.U-731 was sunk in position35°54′N5°45′W / 35.900°N 5.750°W /35.900; -5.750; all 54 crew members perished in the attack.[2]