German submarine U-668

History
Nazi Germany
Name	U-668
Ordered	15 August 1940
Builder	Howaldtswerke, Hamburg
Yard number	817
Laid down	11 October 1941
Launched	5 October 1942
Commissioned	16 November 1942
Fate	Surrendered on 9 May 1945; Sunk on 31 December 1945 as part of Operation Deadlight;
General characteristics
Class and type	Type VIIC submarine
Displacement	769 t (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 × torpedo tubes (four bow, one stern); 14 × 53.3 cm (21 in) torpedoes or 26 TMA mines; 1 × 8.8 cm (3.46 in) deck gun (220 rounds); 2 × twin 2 cm (0.79 in) C/30 anti-aircraft guns;
Service record
Part of:	5th U-boat Flotilla; 16 November 1942 – 31 March 1944; 6th U-boat Flotilla; 1 April – 31 May 1944; 13th U-boat Flotilla; 1 June 1944 – 8 May 1945;
Identification codes:	M 49 834
Commanders:	Oblt.z.S. / Kptlt. Wolfgang von Eickstedt; 16 November 1942 – April 1945; Kptlt. Fritz Henning; April – 9 May 1945;
Operations:	6 patrols:; 1st patrol:; a. 22 May – 25 June 1944; b. 6 – 7 July 1944; 2nd patrol:; 19 July – 27 August 1944; 3rd patrol:; a. 14 September – 3 October 1944; b. 14 October 1944; 4th patrol:; 15 October – 11 November 1944; 5th patrol:; 22 November – 19 December 1944; 6th patrol:; a. 1 March – 17 April 1945; b. 12 May 1945; c. 15 – 19 May 1945;
Victories:	None

German submarine U-668 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 11 October 1941 at the Howaldtswerke yard at Hamburg, launched on 5 October 1942, and commissioned on 16 November 1942 under the command of Oberleutnant zur See Wolfgang von Eickstedt.

Attached to 5th U-boat Flotilla based at Kiel, U-668 completed her training period on 31 March 1944 and was assigned to front-line service.

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-668 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), 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 Siemens-Schuckert GU 343/38–8 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).^[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-668 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 two twin 2 cm (0.79 in) C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.^[1]

Service history

U-668 completed six war patrols with no ships sunk.

Fate

The U-boat surrendered at Narvik, Norway on 9 May 1945. On 31 December 1945 U-668 was sunk by gunfire from HMS Onslaught in position 56°3′N 9°24′W / 56.050°N 9.400°W / 56.050; -9.400 as part of Operation Deadlight.^[2]

References

^ ^a ^b ^c ^d Gröner 1991, pp. 43–46.
^ Busch & Röll 1999b, p. 391.

Bibliography

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. ISBN 1-55750-186-6.
Busch, Rainer; Röll, Hans-Joachim (1999b). 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.