German submarine U-705

German submarine U-705 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.

Commissioned on 30 December 1941, she served with the 5th U-boat Flotilla until 31 July 1942 as a training boat, and as a front boat of 6th U-boat Flotilla under the command of Oberleutnant zur See Karl-Horst Horn, until her sinking on 3 September 1942.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-705 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-705 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
Departing on her first and only patrol on 1 August 1942, U-705 left Kiel to encircle the British Isles and turn back after crossing more than half of the Atlantic. On 15 August while cruising some 550 nmi south-east of Iceland, she caught sight of a number of vessels; Convoy SC 95, and the merchant ship Balladier.

Diving after first being seen, she stayed submerged for nearly four hours before firing a torpedo at the starboard side of the Balladier. Listing to the starboard side, the armed guards were unable to return fire on U-705, with the ship sinking after seven minutes.

On 24 August, the Norwegian corvette HNOMS Potentilla and HMS Viscount (D92) of convoy ON 122 located U-705. Dropping five depth charges from the Viscount, along with a further ten from the Potentilla, the two were unable to cause damage to the boat. A further fifty-seven charges were dropped at her and GS U-135 (1941), finally damaging her stern torpedo tube.

Fate
On 3 September 1942, Armstrong Whitworth Whitleys of No. 77 Squadron RAF dropped depth charges at U-705, causing her to sink with all hands lost in the Bay of Biscay.

Wolfpacks
U-705 took part in one wolfpack, namely:
 * Lohs (11 – 26 August 1942)