Escort Group Escort Groups for convoy protection were a British development in the war at sea during the Second World War . They were a tactical innovation by the Royal Navy in anti - submarine warfare , to combat the threat of the German Navy ' s " wolfpack " tactics . Escort Groups typically consisted of mixed types of small warships that operated together as a permanent team ( sometimes these groups could be formed from a single class e . g . the 1st , 3rd , 4th , 5th , 15th and 21st Escort Groups were composed entirely of Captain - class frigate s ) , defending shipping convoys during the Second World War , and more particularly , during the Battle of the Atlantic . The development of these ' escort groups ' proved an effective means of defending shipping convoys . They were rigorously trained in anti - submarine tactics and had many successes . For example , in a ten - day period in 1941 , four U - boats were sunk with the loss of three of Germany ' s top U - boat commanders . Background . During the first year of the Battle of the Atlantic British convoy protection was the responsibility of the Western Approaches Command ( WAC ) , based first in Plymouth , then , as the focus of the campaign moved after the Fall of France , in Liverpool . Western Approaches Command controlled an array of escort vessels , mainly elderly destroyer s , sloops , naval trawler s and , later , corvette s to escort merchant ships travelling to and from Britain . These were not numerous enough or sufficiently long ranged to provide a full escort service across the Atlantic , but would accompany convoys to and from meeting points at the edge of the Western Approaches , at points thought to be beyond U - boat range . In the beginning convoy escorts were compiled on an ad hoc basis ; the escorts would be dispatched as and when available , and arrive singly or in small groups . Command of the escort force fell to the senior officer present , and could change as each new ship arrived . Any tactical arrangements had to be made on the spot , and communicated by signal lamp to each ship in turn . The ships would be un - coordinated , being unused to working together , and would have no common battle plan or tactics . These deficiencies led to a major defeat in October 1940 when Convoy HX 79 from Halifax to Liverpool was attacked by a wolfpack of five U - boats remaining after an attack on convoy SC 7 . Initially unprotected , a force of 11 warships were assembled but 12 ships in the convoy were sunk from attacks during the night while none of the U - boats were damaged . The loss of ships from both SC 7 and HX 79 gave the impetus for Admiral Percy Noble , the commander - in - chief of WAC , to form discrete groups ; by the beginning of 1941 eight groups had been formed . Service history . In 1941 WAC had 8 escort groups formed . These typically comprised four to eight ships , under the command of an RN officer , usually a Commander or Lieutenant Commander . By operating together under a single leader , groups were able to develop group tactics and practice their use ; with the issue of a single short command the various ships of the group , often out of sight of each other , could be relied upon to act in a co - ordinated fashion . Later these tactics were standardized and taught to all escort group commanders at the Western Approaches Tactical Unit . This level of teamwork was never achieved by the attacking U - Boats . Although the wolfpack was co - ordinated in that a number of boats would be concentrated on a target convoy , once gathered the boats would attack individually without any attempt at further co - operation . It was not unknown for U - boats to get in each other ' s way whilst attacking , or collide with each other . Time and again during the Battle of the Atlantic relatively small , well - handled escort groups were able to frustrate attacks by more numerous groups of U - boats , and ensure the " safe and timely arrival " of their charges . In one example , in November 1942 , Convoy ON 144 of 33 ships from Britain to North America protected by the Mid - Ocean Escort Force B - 6 of five Flower - class corvette s , was attacked by a group of ten U - boats . Over the next three days they fought off attacks by the wolfpack for the loss of five ships and one corvette ; 28 ships arrived safely . Following this action the SOE ( Senior Officer Escort ) was " warmly congratulated " for preventing what could have been a major disaster , and the contrast with HX 79 was apparent .