Attached to 5th U-boat Flotilla based at Kiel, U-643 completed her training period on 30 June 1943 and was assigned to front-line service.
Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-643 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.[2] 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 superchargeddiesel 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).[2]
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).[2] 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-643 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/30anti-aircraft gun. The boat had a complement of between forty-four and sixty.[2]
Service history
On 8 October 1943, while operating against convoy SC 143, U-643 was detected by LiberatorR of No. 86 Squadron RAF. The aircraft strafed the U-boat but had to return to base short on fuel. Another British aircraft, Liberator Z of the same squadron, continued the attack on U-643, which attempted to dive. Four depth charged were dropped in the wake of the diving U-boat, which resulted in an oil spill. Liberator Z returned to the convoy, only to return an hour later to find Liberator T of No. 120 Squadron RAF attacking an U-boat, which turned out to be U-643. The two aircraft attacked with depth charges and strafed the U-boat. When two more Liberators arrived at the scene, the U-boat's crew prepared to abandon ship. Upon arrival of the destroyer HMS Orwell the U-boat was scuttled, 18 survivors were picked up by Orwell.[1]
Busch, Rainer; Röll, Hans-Joachim (1999a). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN1-55750-186-6.
