German submarine U-564

German submarine U-564 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during the Second World War. The RAF sank her in the Bay of Biscay on 14 June 1943.

Construction and commissioning
She was ordered on 24 October 1939 and was laid down on 30 March 1940 at Blohm & Voss, Hamburg, as ' 540'. She was launched on 7 February 1941 and commissioned under her first commander Oberleutnant zur See Reinhard Suhren on 3 April of that year. Her chief engineer under Suhren was Ulrich Gabler. Suhren commanded her for her work-up with the 1st U-boat Flotilla between 3 April and 1 June 1941. She then became a front (operational) boat of the 1st U-boat Flotilla, and set out on her first patrols.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-564 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-564 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.

Early patrols
Her first patrol took U-564 from Kiel to Brest in occupied France, spending a total of 41 days at sea. The patrol brought a number of successes; on 27 June Suhren came across convoy HX 133. He damaged the Norwegian tanker MV Kongsgaard and sank the Dutch SS Maasdam (1921) and the British MV Malaya II that day. He had one further success on that patrol, sinking the Icelandic merchantman SS Hekla on 29 June. U-564 put into Brest on 27 July, having sunk three merchant ships for, and damaged another for 9,467 GRT.

She sailed again from Brest on 16 August, heading into the Atlantic. She came across convoy OG-71 and sank the Irish SS Conlara and the British tug Empire Oak on 22 August. She sank an escort the following day, HMS Zinnia (K98). U-564 returned to Brest on 27 August after 12 days at sea, having sunk three ships for. She sailed again on 16 September, this time encountering convoy HG-75 on 24 October. She sank three British merchantmen that day, SS Alhama, SS Ariosto and SS Carsbreck. U-564 was attacked later in the evening, by a bomb from an aircraft and later by an escort with depth charges. She escaped damage however, and returned to port at Lorient on 1 November having spent 47 days at sea and sunk three ships for 1,687 and 900 tons.

U-564 relocated to La Pallice in early 1942, and sailed from there on 18 January. She sank the Canadian tanker MV Victolite 260 nmi northwest of Bermuda on 11 February 1942, and damaged the British tanker MV Opalia, although not severely (her deck gun firing 83 rounds, but only scoring three hits), on 16 February, before returning to Brest on 6 March, after 48 days on patrol with sunk and  damaged.

Off the American coast
U-564 sailed from Brest on 4 April 1942, to cross the Atlantic and prey on shipping off the North American coast, including Florida. She was in position in early May and on 3 May, secured her first success, sinking the British SS Ocean Venus. On the 4 May, she damaged the British SS Eclipse (1931), and on 5 May she damaged the American SS Delisle. On 8 May she sank the American merchantman SS Ohian, the following day she sank the Panamanian tanker MV Lubrafol. Her final success in American waters was to sink the Mexican tanker SS Potrero del Llano. U-564 arrived back in Brest on 6 June, having spent 64 days at sea and sunk four ships, for, and damaged two ships, for.

U-564 repeated the exercise on her next patrol, departing Brest on 6 July to operate off the coast of South America. Whilst outward-bound across the Atlantic, Suhren came across convoy OS-34 near the Azores, and on 19 July sank the British merchant SS Empire Hawksbill, and damaged the MV Lavington Court (sank 1 August whilst under tow back to the UK). Operating off the northern South America coast, he sank the SS British Consul and the SS Empire Cloud west of Grenada on 19 August and on the 30th, she sank the Norwegian tanker Vardaas north of Scarborough. U-564 arrived back in Brest on 18 September after 72 days on patrol, having sunk five ships for.

Fiedler takes charge
This was Suhren's last patrol as commander of U-564. He left on 1 October to become an instructor, Oberleutnant zur See Hans Fiedler took command. He took the boat on two war patrols in 1943 but failed to hit any enemy ships. On one of these sorties events took a dramatic turn when the U-boat lost a crewman, Fähnrich zur See (Ensign) Heinrich Fuerhake. U-564 was transferred to operate out of Bordeaux in April 1943. She left the French port city for the final time on 9 June with four other outbound U-boats, GS U-185, GS U-358, GS U-634 and GS U-653. A Royal Air Force Short Sunderland spotted the boats and attacked them off Cape Finisterre at 18.59 hours on 13 June. The aircraft targeted U-564 and dropped its bombs, but was shot down by anti-aircraft fire, killing all 11 of the crew. U-564 had sustained heavy damage and turned back, escorted by U-185.

Wolfpacks
U-564 took part in six wolfpacks, namely:
 * Brandenburg (16 – 19 September 1941)
 * Breslau (2 – 29 October 1941)
 * Natter (2 – 8 November 1942)
 * Westwall (8 – 16 December 1942)
 * Seeteufel (21 – 30 March 1943)
 * Löwenherz (1 – 10 April 1943)

Sinking
An Armstrong Whitworth Whitley sighted the two U-boats in the Bay of Biscay the following day and shadowed them. U-564 was unable to dive due to the damage already sustained. By 16:45 hours the Whitley was running low on fuel and attacked U-564. The two U-boats damaged their attacker with anti-aircraft fire but the aircraft's depth charges fatally damaged U-564 and she sank at 17:30 hours. The damaged Whitley was forced to ditch, where a French trawler rescued the crew. There were 18 survivors from U-564 including the commander. GS U-185 picked them up and transferred them to the GERMAN DESTROYER Z24 two hours later.