Early escort groups often contained destroyers, sloops, naval trawlers and, later, corvettes of differing specifications lacking the ability to maneuver together as a flotilla of similar warships, but rigorously trained in anti-submarine tactics to use teamwork emphasizing the unique sensors, weapons, speed, and turning radius of each ship.
Based on experience during World War I, the Admiralty instituted trade convoys in United Kingdom coastal waters from September 1939.
[1] 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 1940 Fall of France, in Liverpool.
[2] The newest and most capable destroyers were assigned to screen capital ships of the Home Fleet; so, to augment the inadequate number of purpose-designed sloops, WAC was allocated a leftover array of limited production prototypes, ships built to foreign specifications, minesweepers, militarized yachts, and fishing trawlers, and survivors of elderly destroyer classes no longer considered suitable for operation with the Home Fleet.
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.
In one example, in November 1942, Convoy ON 144 of 33 ships from Britain to North America protected by the Mid-Ocean Escort Force B6 of five Flower-class corvettes, was attacked by a group of ten U-boats.
[6][7] Following this action, the Senior Officer Escort (SOE) – commander of the group – was "warmly congratulated" for preventing what could have been a major disaster,[7] and the contrast with HX 79 was apparent.