German submarine U-634

History
Nazi Germany
Name	U-634
Ordered	15 August 1940
Builder	Blohm & Voss, Hamburg
Yard number	610
Laid down	23 September 1941
Launched	10 June 1942
Commissioned	6 August 1942
Fate	Sunk 30 August 1943 in the North Atlantic in position 40°13′N 19°24′W / 40.217°N 19.400°W, by depth charges from HMS Stork & HMS Stonecrop.
General characteristics
Class and type	Type VIIC submarine
Displacement	769 tonnes (757 long tons) surfaced; 871 t (857 long tons) submerged;
Length	67.10 m (220 ft 2 in) o/a; 50.50 m (165 ft 8 in) pressure hull;
Beam	6.20 m (20 ft 4 in) o/a; 4.70 m (15 ft 5 in) pressure hull;
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);
Propulsion	2 shafts; 2 × diesel engines; 2 × electric motors;
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	230 m (750 ft); Crush depth: 250–295 m (820–968 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; 6 August 1942 – 31 January 1943; 9th U-boat Flotilla; 1 February – 30 August 1943;
Identification codes:	M 23 270
Commanders:	Oblt.z.S. Hans-Günther Brosin; 6 August 1942 – 2 February 1943; Oblt.z.S. Eberhard Dahlhaus; 28 January – 30 August 1943;
Operations:	3 patrols:; 1st patrol:; 18 February – 23 March 1943; 2nd patrol:; 15 April – 23 May 1943; 3rd patrol:; 12 June – 30 August 1943;
Victories:	1 merchant ship sunk ; (7,176 GRT)

German submarine U-634 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 23 September 1941 by Blohm & Voss, Hamburg as yard number 610, launched on 10 June 1942 and commissioned on 6 August 1942 under Oberleutnant zur See Hans-Günther Brosin.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-634 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 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).^[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-634 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.^[2]

Service history

The boat's career began with training at 5th U-boat Flotilla on 6 August 1942, followed by active service on 1 February 1943 as part of the 9th Flotilla for the remainder of her service. In three patrols she sank one merchant ship, for a total of 7,176 gross register tons (GRT).

Fate

U-634 was sunk on 30 August 1943 in the North Atlantic in position 40°13′N 19°24′W / 40.217°N 19.400°W / 40.217; -19.400, by depth charges from HMS Stork and HMS Stonecrop, escorting the Allied convoys SL 135/MKS 22. All crew members of U-634 died.

Wolfpacks

U-634 took part in five wolfpacks, namely:

Westmark (6 – 11 March 1943)
Amsel (22 April – 3 May 1943)
Amsel 2 (3 – 6 May 1943)
Elbe (7 – 10 May 1943)
Elbe 1 (10 – 14 May 1943)

Summary of raiding history

Date	Ship Name	Nationality	Tonnage (GRT)	Fate^[3]
2 March 1943	Meriwether Lewis	United States	7,176	Sunk

References

^ Helgason, Guðmundur. "The Type VIIC boat U-634". German U-boats of WWII - uboat.net. Retrieved 31 August 2014.
^ ^a ^b ^c ^d Gröner 1991, pp. 43–46.
^ Helgason, Guðmundur. "Ships hit by U-634". German U-boats of WWII - uboat.net. Retrieved 31 August 2014.

Bibliography

Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN 1-55750-186-6.
Busch, Rainer; Röll, Hans-Joachim (1999). Der U-Boot-Krieg, 1939-1945: Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945] (in German). Vol. IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
Gröner, Eric; Jung, Dieter; Maass, Martin (1991). German Warships 1815-1945: U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
Sharpe, Peter (1998). U-Boat Fact File. Great Britain: Midland Publishing. ISBN 1-85780-072-9.