German submarine U-704

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

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.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-704 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-704 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and a 2 cm C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
U-704 set out on its first patrol, a transit to its operational base at Saint-Nazaire on 30 June 1942. 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 British freighter Empire Rainbow, part of convoy Convoy ON-113. Empire Rainbow had already been damaged by a torpedo from GS U-607, and U-704's torpedo sank the freighter.

U-704 carried out a further four operational patrols under the command of Kessler from Saint Nazaire and La Pallice, sinking no further ships. 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.

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.

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)