German submarine U-591 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II.She was laid down on 30 October 1940 by Blohm & Voss, Hamburg as yard number 567, launched on 20 August 1941 and commissioned on 9 October 1941 under Kapitänleutnant Hans-Jürgen Zetzsche.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-591 had a displacement of 769t when at the surface and 871t while submerged. She had a total length of 67.1m (220.1feet), a pressure hull length of 50.5m (165.7feet), a beam of 6.2m (20.3feet), a height of 9.6m (31.5feet), and a draught of 4.74m (15.55feet). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of NaNPS for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of 750PS for use while submerged. She had two shafts and two 1.23abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-591 was fitted with five 53.30NaN0 torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.82NaN2 SK C/35 naval gun, 220 rounds, and a 2sp=usNaNsp=us C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.
The boat's service began on 9 October 1941 with training, followed by active service as part of the 6th U-boat Flotilla. She was transferred to the 11th Flotilla on 1 July 1942 for active service in the North Atlantic operating out of Bergen. The following year, on 1 June 1943, she transferred to 9th Flotilla operating of Brest, France.
In 8 patrols she sank four merchant ships, for a total of, plus one merchant ship damaged.
The first victim of Convoy ONS 154 was the 5,701-GRT Norwegian freighter Norse King, the second in column eleven, on 28 December 1942. U-591 torpedo hit her at 20:04. Badly damaged, Norse King attempted to limp to the Azores but was found by and sent to the bottom.
U-591’s second success was the badly damaged and abandoned 4,871-GRT United Africa Company freighter Zarian with a single torpedo, although she missed the Baron Cochrane
Having recently returned to sea after a long recovery from gunshot wounds, Hans-Jürgen Zetzsche was on target with Convoy SC 121 when he sighted the Empire Impala, hove-to picking up survivors from the torpedoed Egyptian, on 7 March 1943. Of the combined crew of 80 men, from both Egyptian and Empire Impala, only 3 survived.
U-591 was sunk on 30 July 1943 in the South Atlantic near Pernambuco in position -8.6°N -68°W; depth charged by a US Lockheed Ventura aircraft of VB-127. There were 19 dead and 28 survivors.
U-591 took part in nine wolfpacks, namely:
| Date | Ship Name | Nationality | Tonnage (GRT) | Fate[1] | |
|---|---|---|---|---|---|
| 21 December 1942 | Montreal City |  United Kingdom | 3,066 | Sunk | |
| 28 December 1942 | Norse King |  Norway | 5,701 | Damaged | |
| 29 December 1942 | Zarian | United Kingdom | 4,871 | Sunk | |
| 7 March 1943 | Empire Impala | United Kingdom | 6,116 | Sunk | |
| 8 March 1943 | Vojvoda Putnik | 5,879 | Sunk |