German submarine U - 564 German submarine " U - 564 " was a Type VIIC U - boat built for the Nazi German 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 ' werk 540 ' . She was launched on 7 February 1941 and commissioned under her first commander " Oberleutnant " Reinhard Suhren on 3 April of that year . 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 . Operational career . 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 and sank the Dutch and the British that day . He had one further success on that patrol , sinking the Icelandic merchantman on 29 June . " U - 564 " put in to Brest on 27 July , having sunk three merchant ships for , and damaged another for 9 , 467 tons . She sailed again from Brest on 16 August , heading into the Atlantic . She came across convoy OG - 71 and sank the Irish and the British tug " Empire Oak " on 22 August . She sank an escort the following day , the . " 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 , the , and the . " U - 564 " was attacked later in the evening , by a bomb from an aircraft and later by an escort with depth charge s . She escaped damage however , and returned to port at Lorient on 1 November having spent 47 days at sea and sunk three ships for 2 , 587 tons . " U - 564 " relocated to La Pallice in early 1942 , and sailed from there on 18 January . She sank the Canadian tanker northwest of Bermuda on 11 February and damaged the British tanker , 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 the 3rd secured her first success , sinking the British . On the 4th she damaged the British , and on 5 May she damaged the American . On the 8th she sank the American merchantman , the following day she sank the Panamanian tanker . Her final success in American waters was to sink the Mexican tanker . " 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 and on 19 July sank the British merchant ships and . Operating off the northern South America coast , he sank the and the 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 " 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 , , , and . 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 " . 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 . " U - 185 " picked them up and transferred them to the two hours later .