German submarine U - 155 ( 1941 ) German submarine " U - 155 " was a Type IXC U - boat of the Nazi German " Kriegsmarine " built for service during World War II . Her keel was laid down on October 1 , 1940 by AG Weser in Bremen as ' werk ' 997 . She was launched on May 12 , 1941 and commissioned on August 23 , with " Kapitänleutnant " Adolf Cornelius Piening in command . Piening was relieved in February 1944 ( after being promoted to " Korvettenkapitän " ) , by " Oberleutnant zur See " Johannes Rudolph . " Leutnant zur See " Ludwig von Friedeburg relieved Rudolph from August to November 1944 , when Rudolph resumed command for another month . During these four months , " U - 155 " had the youngest U - boat commander during the war since Von Friedeburg was only 20 years old . In December , " Kptlt . " Erwin Witte took over , and was relieved in April 1945 by " Oblt . " Friedrich Altmeier . Altmeier commanded the boat for one month before being ordered to surrender her . Operational career . " U - 155 " conducted 10 patrols , sinking 26 ships totalling ( ) , one warship of 13 , 785 tons and damaging one auxiliary warship of 6 , 736 GRT . She was a member of one wolfpack . She sank the escort carrier and the British troop transport ship " Ettrick " on November 15 , 1942 , she also damaged the requisitioned cargo ship " USS Almack " on the same day . On May 4 , 1945 , the boat shot down a P - 51 Mustang of No . 126 Squadron RAF . 1st patrol . " U - 155 " left Kiel on her first patrol on February 7 , 1942 . Her route took her ' up ' the North Sea , through the ' gap ' between the Faroe and Shetland Islands and into the Atlantic . South of Cape Farewell in Greenland , she sank the " Sama " and the Adellen " on the 22nd . She then moved on to the US east coast , sinking the " Arabutan " about off Cape Hatteras , North Carolina on March 7 . Tragedy struck on the 10th when the First Watch Officer ( 1WO ) " Oberleutnant zur See " Gert Rentrop was washed overboard . The boat docked at Lorient on the French Atlantic coast on March 27 . 2nd patrol . Having left Lorient on April 24 , 1942 , " U - 155 " steamed to the eastern Caribbean Sea and that portion of the Atlantic adjacent to it . She attacked the " Brabant " southwest of Grenada on May 14 . The ship sank in eight minutes . The U - boat sank another six ships ; one of them , the " Sylvan Arrow " , was torpedo ed on May 20 , but did not go down until the 28th , following a salvage attempt . The submarine returned to Lorient on June 14 . 3rd patrol . " U - 155 " s third and most successful foray was conducted in similar waters to her second effort , beginning in Lorient on July 9 . She sank the " Barbacena " with torpedoes east of Barbados , but others , such as the " Piave " , went to the bottom with the more economic deck gun . Another victim , the " Cranford " , met her end within three minutes . Part of her cargo was 6 , 600 tons of chrome ore . Two injured survivors were treated on " U - 155 " before water , supplies and directions were handed over to their colleagues . The submarine ' s skipper apologized for sinking one ship ( the " Empire Arnold " on August 4 ) , to the Chief Officer , who told him it was a bad business and wished it [ the war ] was over . Piening replied : " So do I " . " Maschinengefreiter " Konrad Garneier was lost overboard during an air attack on August 19 . In all , the boat sank ten ships , a total of 43 , 514 tons . 4th patrol . A spread of four torpedoes resulted in three hits , one " aal " ( eel : U - boat slang for torpedo ) , damaged the USS " Almaack " , a US Navy - requisitioned cargo transport ; two others sank HMS " Avenger " , an escort aircraft carrier and the " Ettrick " , a British troop transport on 15 November 1942 northwest of Gibraltar . Of 526 men on " Avenger " , there were 12 survivors . " Etterick " s master was awarded the Order of the British Empire ( OBE ) . The boat also sank the " Serroskerk " in mid - Atlantic . There were no survivors . 5th patrol . " U - 155 " s fifth sortie involved her move to the western Caribbean and southern Florida . She sank the " Lysefjord " west of Havana on April 2 , 1943 , and on April 3 , sank the " Gulfstate " about east northeast of Marathon Key , Florida . On the return journey , she was attacked by an unknown aircraft on April 27 northwest of Cape Finisterre , Spain . In 2013 , some 70 years later , the oil tanker " Gulfstate " was once again a target , this time of the National Oceanic and Atmospheric Administration ' s Remediation of Underwater Legacy Environmental Threats ( RULET ) project , which hunts down potential sources of oil pollution from sunken vessels . 6th patrol . To try and counter the air threat , " U - 155 " was grouped together with " U - 68 " , " U - 159 " , " U - 415 " and " U - 634 " in the Bay of Biscay . The little flotilla was attacked by four De Havilland Mosquito s on June 14 - three from No . 307 ( Polish ) Squadron RAF and one from No . 410 Squadron RCAF . One aircraft , hit in the port engine , was forced to break off its attack and return to base where it made a belly landing . Five men in the boat ' s crew were wounded , they were treated by " U - 68 " s doctor on the return to Lorient , which was reached on June 16 . 7th and 8th patrols . Patrol number seven was as long as any of the others , to a point northeast of the Cape Verde Islands ; but the boat did not find any targets . The submarine ' s eighth outing took her toward the northeast coast of Brazil . While sinking the " Siranger " she took the third mate prisoner ( he had been wounded and was operated - on by the boat ' s doctor ) . He was taken back to Lorient and was eventually transferred to the POW camp at Milag Nord near Bremen . 9th and 10th patrols . " U - 155 " s ninth patrol was , at 105 days , her longest , but like her seventh , was devoid of success . On June 23 , 1944 , Mosquitos of 248 Squadron attacked , killing " Matrosenobergefreiter " Karl Lohmeier and " Mechanikerobergefreiter " Friedrich Feller and wounding seven others . Her tenth and final sally was the last by a U - boat from Lorient , which she left on September 9 , 1944 . By a circuitous route , she returned to Germany , docking at Flensburg on October 21 . Fate . On June 30 , 1945 , she was transferred from Wilhelmshaven to Loch Ryan , Scotland for Operation Deadlight on June 30 , 1945 and sunk on December 21 the same year . Post war . " U - 155 " lies at a depth of . She was located and identified in 2001 by a team of divers led by nautical archaeologist Innes McCartney , revealing the wreck was lying upright on the sea bed and largely intact . Her crew held their 25th reunion in 1995 with former " Oberleutnant " Johannes Rudolph and one of the Mosquito pilots who attacked the boat in June 1944 ' on board ' .