Convoy SC 129 SC 129 was a North Atlantic convoy of the SC series which ran during the battle of the Atlantic in World War II . It was one of several convoy battles that occurred during the crisis month of May 1943 . Background . SC 129 was an east bound convoy of 25 ships , plus local contingents , which sailed from New York on 2 May 1943 bound for Liverpool and carrying war materials . Mid - Ocean Escort Force group B2 joined the convoy from St Johns on 6 May . Escort group B2 was led by Cdr D MacIntyre in HMS " Hesperus " ; other ships of this group were destroyer " Whitehall " and five corvettes . They were joined for the voyage by two armed trawlers , plus a rescue ship and an oiler . Arrayed against them in the North Atlantic were patrol lines " Rhein " , " Elbe " and " Drossel " , though although in the event only " Elbe " , re - configured and comprising 21 U - boats , engaged SC 129 . Action . First contact with the convoy was made on 11 May by " U - 504 " , which called up other boats from " Elbe " and commenced shadowing . The radio activity alerted the Admiralty to the threat , and they ordered Support Group 5 , comprising escort carrier " Biter " and four destroyers to join . SG 5 was at that time supporting HX 237 , under attack by boats from " Rhein " and " Drossel " , but was then in range of Coastal Command aircraft , and it was decided SC 129 was in more need . The report by " U - 504 " had brought up about a dozen U - boats , and on the evening of 11 May one of these , " U - 402 " , slipped past the escorts and torpedoed two ships . These were the freighter " Antigone " , and the Norwegian freighter " Grado " . Both ships sank , " Antigone " with the loss of three of her crew . MacIntyre was , in his own words , “ furious ” that ships under his group ’ s protection had been sunk ; in the previous nine months they had escorted tens of convoys without loss . MacIntyre organized a vigorous hunt for the U - boat ; she was found by " Gentian " , attacked with depth - charges , and so badly damaged she was forced to abandon her patrol and return to base . Later that night " Hesperus " got a contact with " U - 223 " and attacked ; by depth - charge and ramming . " U - 223 " was also so badly damaged she was forced to retire . On returning to the convoy " Hesperus " found another U - boat in the early hours of 12 May . This was " U - 186 " , tracking the convoy . " Hesperus " quickly closed in , and as the U - boat crash - dived , attacked with depth - charges . This time the boat was destroyed , all hands were lost . During 12 May the assembled U - boats made over a dozen separate attempts to penetrate the escort screen , but an aggressive defence by the warships , despite being low on fuel and ammunition , prevented any losses . On 13 May the convoy was joined by " Biter " and her group ; " Hesperus " and her group were able to re - fuel and re - arm , and " Biter " was able to mount continuous air patrols . At this BdU saw there was nothing to be achieved , and the attack by the " Elbe " boats was called off , though they continued to shadow . On 17 May this too was abandoned , and " Elbe " was disbanded . During this period , one of the " Drossel " boats , " U - 607 " , encountered a neutral Irish freighter , " Irish Oak " , and on 15 May torpedoed her . The incident caused a political controversy in Ireland , as there were allegations that " Irish Oak " had warned the convoy of the presence of U - boats . The U - boat commander received a mild reprimand . SC 129 arrived without further incident in Liverpool on 22 May 1943 . Aftermath . SC 129 was a success for the Allies . Despite the loss of two ships , 23 ships had arrived safely . Added to this , an attack by a wolfpack of 12 U - boats had been beaten off , one U - boat had been destroyed , and two more so badly damaged they had to return to base . The convoy was another in a series of set - backs suffered by the U - boat Arm collectively known as Black May .