History
Nazi Germany
Name	U-639
Ordered	20 January 1941
Builder	Blohm & Voss, Hamburg
Yard number	615
Laid down	31 October 1941
Launched	22 July 1942
Commissioned	10 September 1942
Fate	Torpedoed and sunk by the Soviet submarine S-101 in the Kara Sea on 28 August 1943
General characteristics
Class and type	Type VIIC U-boat
Displacement	769 tonnes (757 long tons) surfaced 871 t (857 long tons) submerged
Length	67.10 m (220.1 ft) o/a 50.50 m (165.7 ft) pressure hull
Beam	6.20 m (20.3 ft) o/a 4.70 m (15.4 ft) pressure hull
Draught	4.74 m (15.6 ft)
Propulsion	3,200 PS (2,400 kW; 3,200 bhp) surfaced 750 PS (550 kW; 740 shp) submerged
Speed	17.7 knots (32.8 km/h; 20.4 mph) surfaced 7.6 knots (14.1 km/h; 8.7 mph) submerged
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
Test depth	Calculated crush depth: 220 m (720 ft)
Complement	4 officers, 40–56 enlisted
Armament	5 × 53.3 cm (21 in) torpedo tubes (four bow, one stern) 14 × torpedoes or 26 TMA mines 1 × 8.8 cm (3.46 in) deck gun (220 rounds) 1 × twin 2 cm (0.79 in) C/30 anti-aircraft gun
Service record
Part of:	5th U-boat Flotilla 10 September 1942 – 31 March 1943 11th U-boat Flotilla 1 April – 31 May 1943 13th U-boat Flotilla 1 June – 28 August 1943
Identification codes:	M 50 196
Commanders:	Oblt.z.S. Walter Wichmann 10 September 1942 – 28 August 1943
Operations:	4 patrols: 1st patrol: 24 March – 25 April 1943 2nd patrol: a. 12 May – 7 June 1943 b. 8 June 1943 c. 14 – 15 June 1943 3rd patrol: a. 24 July – 4 August 1943 b. 5 August 1943 4th patrol: 11 – 28 August 1943
Victories:	None

German submarine U-639 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 31 October 1941 at Blohm & Voss in Hamburg as yard number 615, launched on 22 July 1942 and went into service on 10 September 1942. U-639 spent her entire career operating out of Norway. Over the course of four patrols she neither sank nor damaged any ships, and was sunk by the Soviet submarine S-101 in the Kara Sea while on a minelaying mission.^[1][2]

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-639 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.^[3] 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 BBC 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).^[3]

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).^[3] 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-639 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.^[3]

• Helgason, Guðmundur. "The Type VIIC boat U-639". German U-boats of WWII - uboat.net. Retrieved 30 December 2014.

76°49′N 69°42′E / 76.817°N 69.700°E / 76.817; 69.700