German submarine U-704

German submarine U-704 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

History
Nazi Germany
Name	U-704
Ordered	9 October 1939[1]
Builder	HC Stülcken & Sohn, Hamburg
Yard number	763
Laid down	26 August 1940[1]
Launched	28 August 1941[1]
Commissioned	18 November 1941[1]
Fate	Scuttled on 30 April 1945[1]
General characteristics
Class & 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 1 × 8.8 cm (3.46 in) deck gun (220 rounds) 1 x 2 cm (0.79 in) C/30 AA gun
Service record
Part of:	8th U-boat Flotilla 18 November 1941 – 30 June 1942 7th U-boat Flotilla 1 July 1942 – 1 April 1943 21st U-boat Flotilla 1 April – 31 May 1943 24th U-boat Flotilla 1 June – 31 August 1943 23rd U-boat Flotilla 1 September 1943 – 31 July 1944 21st U-boat Flotilla 1 August 1944 – 24 March 1945
Identification codes:	M 43 929
Commanders:	Oblt.z.S. / Kptlt. Horst Wilhelm Kessler 18 November 1941 – April 1943 Oblt.z.S. Karl-Heinz Hagenau 12 Jun 1943 – April 1944 Lt.z.S. Gerhard Ady April – July 1944 Oblt.z.S. Wolfgang Schwarzkopf 6 August – 18 December 1944 Oblt.z.S. Gerhard Nolte 19 December 1944 – 24 March 1945
Operations:	5 patrols:[1] 1st patrol: 30 June – 16 August 1942 2nd patrol: 9 – 15 September 1942 3rd patrol: 5 October – 23 November 1942 4th patrol: a. 1 – 2 January 1943 b. 7 January – 12 February 1943 5th patrol: a. 14 March – 5 April 1943 b. 6 – 11 April 1943
Victories:	1 merchant ship sunk (6,942 GRT)[1]

Commissioned on 18 November 1941 under the command of Kapitänleutnant Horst Wilhelm Kessler, U-704 carried out training operations as part of the 8th U-boat Flotilla until 30 June 1942.^[1]

Design

German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-704 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 AEG GU 460/8–27 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-704 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 a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.^[2]

Service history

U-704 set out on its first patrol, a transit to its operational base at Saint-Nazaire on 30 June 1942.^[3] During this patrol, U-704 formed part of wolfpack "Wolf" which was to patrol between Iceland and Greenland, out of the range of allied air cover. On 26 July 1942, U-704 torpedoed the 6,942 GRT British freighter Empire Rainbow, part of convoy Convoy ON 113. Empire Rainbow had already been damaged by a torpedo from U-607, and U-704's torpedo sank the freighter.^[3][4]

U-704 carried out a further four operational patrols under the command of Kessler from Saint Nazaire and La Pallice, sinking no further ships.^[3] U-704 did fire four torpedoes at the troopship Queen Elizabeth on 9 November 1942, with Kessler claiming a hit, although Queen Elizabeth was undamaged.^[5]

Fate

U-704 then served as a training submarine in the Baltic Sea for the rest of the war, and was scuttled at Vegesack on 30 April 1945.^[1]

Wolfpacks

U-704 took part in seven wolfpacks, namely:

• Wolf (13 – 31 July 1942)
• Pirat (31 July – 3 August 1942)
• Steinbrinck (3 – 11 August 1942)
• Panther (10 – 20 October 1942)
• Veilchen (20 October – 7 November 1942)
• Habicht (10 – 19 January 1943)
• Haudegen (19 January – 9 February 1943)

Summary of raiding history

Date	Ship Name	Nationality	Tonnage (GRT)	Fate[6]
26 July 1942	Empire Rainbow	United Kingdom	6,942	Sunk