Convoy HX 72 HX 72 was a North Atlantic convoy of the HX series which ran during the battle of the Atlantic in World War II . Background . HX 72 was an east - bound convoy of 43 ships which sailed from Halifax on 9 September 1940 bound for Liverpool and carrying war materials . The convoy , made up of contingents from Halifax , Sydney and Bermuda was led by Commodore HH Rogers RNR in " Tregarthen " . Escorts at this stage of the campaign were generally meagre ; convoys generally were unescorted , or had just an Armed Merchant Cruiser ( AMC ) as protection against surface raiders until reaching the Western Approaches . HX 72 ' s ocean escort was the AMC " Jervis Bay " , though at sunset on 20 September " Jervis Bay " detached to meet a west - bound convoy . HX 72 wasn ’ t due to meet the Western Approaches escort until the afternoon of 21st , so HX 72 was unprotected when it was sighted at last light by Prien of . The U boat Arm ( UBW ) was also sparse , able to maintain only a few boats at any one time in the North Atlantic , operating at the edge of the Western Approaches to intercept convoys before their escort had joined . " U 47 " was on weather duty , her armament depleted after an attack on Convoy SC 2 earlier that month , and was able only to report contact . After reporting the convoy Prien shadowed the convoy , while U - boat Control ( BdU ) summoned all available U - boats . During night and following day a pack of 6 boats was gathered , and , which were nearby , and others en route from Germany . Action . Kretschmer , in " U - 99 " made contact around midnight of 20 / 21 September and attacked , hitting " Invershannon " . Rogers ordered a turn to port to try and shake off the attack , but this failed ; " U - 99 " attacked again , hitting " Baron Blythswood " ( which sank ) and " Elmbank " ( which was disabled ) . " U - 99 " and " U - 47 " then attacked " Elmbank " with gunfire , but she did not sink until morning , at which point " U - 99 " left the scene to return to Lorient . Rogers dropped smoke and turned again , to try and shake off his pursuers , but failed once more ; " U - 47 " and " U - 48 " continued to shadow throughout the daylight on the 21st . During 21 September , Prien and Bleichrodt were joined by 4 other boats of 2nd U - boat Flotilla , , , and , while arrived at nightfall . However that afternoon the Western Approaches escort also arrived , causing the U boats to draw back . At this stage , escorts usually arrived piecemeal , but by evening 5 warships had arrived , sloop " Lowestoft " , destroyer " Shikari " and 3 corvettes , " Calendula " , " Heartsease " and " La Malouine " . At nightfall on 21 / 22 September " U - 100 " struck , entering the convoy to attack at close range . Attacking before moonrise Schepke hit three ships within minutes , causing confusion . " Canonesa " , " Torinia " and " Dalcairn " were sunk , and the convoy began to scatter in confusion . The escort sought to retaliate , but searched outside the convoy perimeter , where the rest of the pack was gathered ; they were unable to find Schepke , but were able to frustrate further attacks . " U - 48 " hit " Broompark " , which was damaged , but no other boat was successful . Just after midnight " U - 100 " struck again , sinking 3 more ships , , " Scholar " , and " Frederick S Fales " . She also attacked " Harlingen " , but was spotted ; " Harlingen " avoided the torpedoes aimed at her , and returned fire with her stern gun , scoring several hits , but causing little damage . As the convoy broke up , two more ships were hit ; " U - 100 " sank " Simla " , while " U - 32 " damaged " Collegian " . This was the end of the action ; HX 72 was scattered , but the U – boats were unable to pursue , as the presence of the escorts had forced them to submerge . The remaining ships of HX 72 proceeded independently , while the escorts tried to gather the convoy back together , but no further attacks took place and all remaining ships reached port safely . Conclusion . HX 72 had lost 11 ships of 72 , 727 gross register tons , of which Kretschmer sank three and Schepke seven ships . Whilst undoubtedly a victory , and a vindication of Donitz ’ s wolfpack tactic , most of the UBW ' s successes were achieved by two of its aces using their high - risk tactic of penetrating the convoy to attack from within . The other boats following the more traditional approach from the flank , and at longer range , were far less successful . Table . Allied ships sunk