B - 7 Escort Group ( Royal Navy ) B - 7 Escort Group was a British formation of the Royal Navy which saw action during the Second World War ; principally in the Battle of the Atlantic . Formation . B - 7 Escort Group ( B - 7 EG ) was one of seven such British naval groups which served with the Mid - Ocean Escort Force ( MOEF ) . It provided convoy protection in the most dangerous midsection of the North Atlantic route . The MOEF was originally to be five American , five British and four Canadian groups . B - 7 was formed in the spring of 1942 , following the inability of the USN to form groups A - 4 and A - 5 due to other commitments . To replace them , two new escort groups , B - 6 and B - 7 , were formed . Service history . Led by HMS " Firedrake " , under the leadership of Commander William Banks , B - 7 comprised six Flower class corvette s ; HMS " Loosestrife " from the disbanded American group A - 5 , and " Alisma " , " Coreopsis " , " Jonquil " , " Pink " and " Sunflower " . These were joined later by the destroyers HMS " Chesterfield " and " Ripley " . B - 7 ’ s first convoys , in the spring of 1942 , were uneventful , and as the pace of the Battle of the Atlantic hotted up in the summer and autumn , the group ' s charges were escorted without loss . But in December , while escorting ON 153 , the convoy came under attack , and three ships were sunk . During this action , on 11 December , " Firedrake " was torpedoed by " U - 211 " and sank with the loss of 168 of her crew , including her current commander , and group SOE ( Senior Officer - Escort ) , Cdr Eric Tilden . Initially 35 survived the torpedoing , but only 27 managed to get on board " Sunflower " , which was under the command of Captain John Treasure Jones . B - 7s new SOE was Cdr Peter Gretton , of HMS " Duncan " , a tough and capable leader , who quickly moulded the group to his own image . At this point B - 7 comprised the destroyers " Duncan " , " Vidette " , the frigate HMS " Tay " , and the corvettes HMS " Alisma " , " Loosestrife " , " Pink " , " Sunflower " and " Snowflake " . After several convoys had been escorted without loss , B - 7 covered HX 231 in April 1943 . This came under attack by the " Lowenherz " U - boat group , which sank six ships , but lost two submarines destroyed and five damaged . In May 1943 , B - 7 escorted ONS 5 , sometimes regarded as the turning point of the Atlantic campaign . < br > In a week long battle against three U - boat groups , " Star " , " Amstel " and later " Fink " , ONS 5 saw the loss of 13 ships , for the destruction of six U - boats . At least four of these were credited to ships of the B - 7 EG . Later that month returning with SC 130 , B - 7 saw the destruction of between three and five U - boats ( sources vary ) for no losses . at least one of these was credited to ships of B - 7 EG . A series of uneventful convoys followed , as the U - boat Arm withdrew from the North Atlantic after ' Black May ' , while Gretton lobbied for a chance for B - 7 to operate as a Support Group . In October 1943 this was given , as the German U - boat Arm launched its autumn offensive . B - 7 was involved in the battles for convoys ONS 20 and ON 206 , ON 207 and ON 208 , during which period nine U - boats were destroyed . The battle for ONS20 / 206 saw six U - boats sunk , of which " U - 631 " was credited to " Sunflower " and another , " U - 844 " , was damaged by " Duncan " , to be destroyed later in an air attack . ON 207 saw three U - boats destroyed ; one , ( " U - 282 " ) by ships of B - 7 , another was shared with aircraft . During this period B - 7 had steamed 6 , 700 miles , crossing back and forth across the Atlantic five times . The group members had refueled at sea on six occasions , and had also re - armed with depth charges at sea . Following this B - 7 returned to escort duty on the North Atlantic route , continuing without major incident until the group was disbanded in the summer of 1944 as part of the preparations for Operation Neptune , the naval contribution to the Normandy invasion . Senior Officer Escort . Table