German submarine U-617

German submarine U-617 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 31 May 1941 by Blohm & Voss in Hamburg as yard number 593, launched on 14 February 1942 and commissioned on 9 April under Kapitänleutnant Albrecht Brandi.

The boat's service began on 9 April 1942 with training as part of the 5th U-boat Flotilla. She was transferred to the 7th flotilla on 1 September 1942 and moved on to the 29th flotilla on 1 December 1942.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-617 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 Brown, Boveri & Cie GG UB 720/8 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-617 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
In seven patrols she sank eight ships for a total of, plus two warships and one auxiliary warship.

Wolfpacks
In addition she took part in five wolfpacks, namely:
 * Pfeil (12 – 22 September 1942)
 * Blitz (22 – 26 September 1942)
 * Tiger (26 – 30 September 1942)
 * Delphin (4 – 10 November 1942)
 * Wal (10 – 15 November 1942)

Fate
She ran aground on 12 September 1943 at position 35.63333°N, -3.45°W near Melilla after a sustained air attack by Leigh light-equipped RAF Wellington bombers from 179 Squadron.

All crew members were able to evacuate the stricken sub and subsequently interned by the Spanish authorities. They were later repatriated to Germany.

The abandoned submarine was then finished off with combined RAF Hudson and FAA Swordfish aircraft from Gibraltar and gunfire from HMS Hyacinth (K84) and HMAS Wollongong (J172).