Wolf pack Hai Hai ( English : " Shark " ) was a wolfpack of German U - boat s that operated from 3 to 21 July 1942 in the Battle of the Atlantic during World War II . They attacked the Liverpool to Freetown , Sierra Leone convoy OS - 33 , sinking eight ships for a total of . Ships hit by this Wolfpack . Avila Star . At 00 : 36 on 6 July , after chasing her for five hours , " U - 201 " hit the unescorted 14 , 443 ton British Blue Star Line passenger ship " Avila Star " with two G7e torpedo es 90 miles east of San Miguel , Azores . Another torpedo was fired at 00 : 54 and failed to explode , but another , four minutes later , delivered the coup de grâce . The ship capsized and sank an hour later . The master , 66 crew and 17 passengers were lost , and the remaining 112 ( 93 crewmen , 6 gunners and 13 passengers ) were later rescued . Cortona . At 00 : 22 on 12 July , the 7 , 093 ton British merchant ship " Cortona " , dispersed from Convoy OS - 33 , was struck by a torpedo from " U - 116 " , and three minutes later by another from " U - 201 " . Another torpedo from " U - 201 " struck amidships at 00 : 41 and caused the ship to sink after about an hour . Of the crew , 29 men and 2 gunners were lost , while the Master , 18 crew and 4 gunners were picked up in their lifeboat ten days later by the destroyer . Port Hunter . At 01 : 47 on 12 July the 8 , 826 ton British merchant ship " Port Hunter " of Convoy OS - 33 was struck by a torpedo from " U - 582 " . The ship , whose cargo included ammunition and depth charges , suffered several heavy detonations , and sank within two minutes . The Master , 68 crew , 14 gunners , and 5 passengers were lost , the only survivors being three crewmen who had been sleeping on deck , who were blown into the water and survived by clinging to wreckage until rescued by after seven hours in the sea . Shaftesbury . At 09 : 45 on 12 July , the 4 , 284 ton British merchant ship " Shaftesbury " dispersed from Convoy OS - 33 was hit by two torpedoes from " U - 116 " and sank in 15 minutes . There were no losses among the crew , although the Master , Uriel Eynon , was taken prisoner by the U - boat , returned to Germany , and held at the Milag Nord POW camp . The second officer and 22 crew were picked up on 23 July by the " Tuscan Star " , while the chief officer and 20 survivors made landfall at Villa Cisneros , Spanish Sahara . Siris . At 04 : 13 on 12 July , the 5 , 242 ton British merchant ship " Siris " , dispersed from convoy OS - 33 , was hit by a torpedo from " U - 201 " . Damaged and alone she finally sank at 06 : 26 after the U - boat surfaced and fired 100 rounds from her deck gun at the ship . In the attack a crewman and two gunners were killed , while the master , 46 crew and five gunners abandoned ship , and were picked up ten days later by . Sithonia . At 02 : 21 on 13 July , the 6 , 723 ton British merchant ship " Sithonia " , dispersed from convoy OS - 33 , was torpedoed and sunk by " U - 201 " , killing 7 of the crew . The Master and 20 men made landfall at Timiris , Senegal , after 18 days at sea , and were interned by the Vichy French , while the chief officer and 24 men were picked up by a Spanish fishing vessel after 14 days . British Yeoman . " U - 201 " struck again at 01 : 46 on 15 July , sinking the unescorted 6 , 990 ton British tanker " British Yeoman " with a single torpedo after chasing her for about 14 hours . The tanker , loaded with 9 , 700 tons of Admiralty fuel oil , immediately caught fire . The next morning the U - boat returned to the scene of the attack and found the stern of the ship still floating , and sank it with 61 rounds from her deck gun . Only 10 of the crew of 53 survived . Empire Attendant . At 03 : 30 on 15 July " U - 582 " torpedoed and sank the 7 , 524 ton British merchant ship " Empire Attendant " south of the Canary Islands . There were no survivors from her crew of 59 . References .