German submarine U - 539 German submarine " U - 539 " was a Type IXC / 40 U - boat of the Nazi German " Kriegsmarine " during World War II . The submarine was laid down on 8 May 1942 at the Deutsche Werft yard in Hamburg as ' werk ' 360 , launched on 4 December 1942 , and commissioned on 24 February 1943 under the command of " Oberleutnant zur See " Hans - Jürgen Lauterbach - Emden . After training with the 4th U - boat Flotilla in the Baltic Sea , the boat was transferred to the 10th U - boat Flotilla for front - line service on 1 July 1943 . She carried out three war patrols , sinking one ship and damaged two more . Transferred to the 33rd U - boat Flotilla on 1 October 1944 , she sailed on no further patrols , and surrendered to Allied forces in May 1945 . Transferred from Bergen , Norway , to Loch Ryan , Scotland , she foundered on 4 December 1945 while being towed to the scuttling grounds as part of " Operation Deadlight " . Service history . 1st patrol . The U - boat sailed from Kiel on 4 September 1943 for a three - day voyage to Bergen , before commencing her first war patrol on the 14th . " U - 539 " sailed out into the north Atlantic , and patrolled the waters between Iceland and Greenland . She had no successes , and was attacked by aircraft three times . On 21 September the U - boat was attacked by a British Lockheed Hudson bomber of No . 269 Squadron RAF , southeast of Iceland . The submarine avoided the aircraft ' s bombs and depth charges , and escaped by diving . On 4 October a British B - 24 Liberator bomber of 120 Squadron , escorting Convoy ONS - 19 attacked , but was hit by the U - boat ' s flak , setting both starboard engines on fire and causing it to crash , killing all eight crew . The aircraft ' s depth charges caused only minor damage , and a crewman was slightly wounded by strafing . Finally , on 8 October , an unknown Liberator southeast of Greenland dropped two depth charges , causing serious damage to the U - boat . The U - boat arrived at Lorient in occupied France on 23 October 1943 after 40 days at sea . 2nd patrol . " U - 539 " departed Lorient on 2 January 1944 , as the first U - boat to sail on combat patrol equipped with the " Schnorchel " breathing device . She sailed across the Atlantic to the waters south of Newfoundland , but had no successes . She returned to Saint - Nazaire on 21 March . 3rd patrol . The U - boat departed from Saint - Nazaire for her third and final war patrol on 1 May 1944 . She sailed back across the Atlantic and into the Caribbean Sea . There , on 5 June , she torpedoed and sank the 1 , 517 ton Panama - registered Danish ship " Pillory " off Puerto Rico with the loss of 25 from her crew of 47 . On 11 June , she fired two torpedoes at the 2 , 701 ton Dutch tanker " Casandra " , before surfacing to fire at the ship with her deck gun . However the ship fought back and damaged the U - boat with machine - gun fire , forcing her to break off the attack . The next day , 12 June , an American Mariner patrol bomber attacked the U - boat , but she got away once again . On 4 July , the " U - 539 " , attacked the 10 , 195 ton American Type T2 tanker " Kittanning " , about 40 miles northeast of Cristóbal , Panama , and hit her with three torpedoes , ripping a hole 65 feet long and 20 feet high on her starboard side . The crew of 74 abandoned ship in four lifeboats , but the tanker remained afloat . Two Coast Guard cutter s , and arrived to pick up the survivors and take the ship in tow to Cristobal . " U - 539 " arrived at Flensburg on 22 September , after a patrol lasting 145 days , her longest . Later career . In mid - April 1945 " U - 539 " sailed to Horten , then to Bergen in early May , arriving there three days before the German surrender on 8 May . The U - boat was transferred from Bergen to Loch Ryan in Scotland on 30 May 1945 for Operation " Deadlight " . On 4 December 1945 , while under tow to the scuttling grounds she foundered in position .