German submarine U - 75 ( 1940 ) German submarine " U - 75 " was a Type VIIB U - boat of the Nazi German " Kriegsmarine " during World War II . " U - 75 " was moderately successful in her early career in the Battle of the Atlantic , but in autumn 1941 she was dispatched to the Mediterranean Sea with poor results , leading to the eventual destruction of the boat and her crew . She was laid down on 15 December 1939 at the Bremer Vulkan - Vegesacker Werft ( yard ) , in Bremen as " Werk " 3 , launched on 18 October 1940 and commissioned on 19 December under the command of " Kapitänleutnant " ( " Kptlt . " ) Helmuth Ringelmann . " U - 75 " carried out training with the 7th U - boat Flotilla in December 1941 until March 1941 . She then became operational with the same organization until October . After that , she was reassigned to the 23rd flotilla . War patrols . 1st patrol . Ringelmann was a good sea officer , who made an impact within three weeks of the boat ' s initial patrol starting , when on 29 April the submarine torpedoed and sank the 10 , 000 ton liner in the Central North Atlantic Ocean , killing fifteen sailors and one passenger . 2nd and 3rd patrols . This success was followed on her second foray with another victim , this time a Dutch freighter , the " Elbergen " , which went down about north of the Azores . As the Germans watched her demise , the U - boat was illuminated by a searchlight which was hurriedly extinguished by fire from the boat ' s AA gun . On her third patrol " U - 75 " sank two British cargo ships - the " Harlingen " and the " Cape Rodney " both west of Ireland on 5 August 1941 . The latter ship was taken in tow after being hit , but foundered west of Ushant on the 9th . These operations were conducted from the new submarine base at Saint - Nazaire in France , which provided type VII boats like " U - 75 " with a greater patrol range and cruising ability , thus conferring an essential advantage . 4th patrol . The boat ' s fourth patrol was more unusual , requiring her to slip unnoticed through the heavily defended Strait of Gibraltar and into the Mediterranean to attack allied shipping operating from Gibraltar , Malta and Egypt . She was accompanied in this task by , , , and , which together formed the ' Goeben ' group , ( so - named for the German battleship of the same name which had operated in the Mediterranean in 1914 ) . For these operations , " U - 75 " s home base was now Salamis in Greece , where she arrived on 2 November . On the journey there , the boat had taken a successful detour along the Libyan coast to see if she could catch any British resupply convoys . On 12 October she had seen just such a convoy and managed to sink two landing craft with gunfire before she escaped . 5th patrol and loss . Her final patrol was from 22 December 1941 , and consisted of a similar sweep along the Libyan coast . On 28 December , six days since leaving Salamis , a small coastal convoy was spotted off Mersa Matruh , " U - 75 " launched an attack which sank the small British freighter . The convoy ' s escorts had spotted the U - boat however , and ran the submarine down and dropped depth charge s on the boat . The explosions forced " U - 75 " to the surface , where 30 of her crew were rescued and taken prisoner by her erstwhile opponent before the boat heeled over and sank , taking 15 men with her , including her only captain .