from The Ships of Canada's Naval Forces 1910-1981
by Ken Macpherson and John Burgess

Westbound Convoys - There were seven series of convoys (in total) associated with the transatlantic crossing as shown in the chart below. Westbound convoys were at first escorted to 12/13° W and then dispersed, but soon afterward this was extended to 15° W. In July 1940, it was extended to 17° W and by October 1940, convoys were dispersed at 19° W, some 400 miles west of Ireland. In April 1941, with the acquisition of a fueling base in Ireland, the dispersal point was shifted to 35° W, more than halfway across the Atlantic. By June 1941, with the formation of Newfoundland Force, it was possible to provide continuous escort across the Atlantic. Convoys were escorted to approximately 61° N:25° W (south of Iceland), where a group from Iceland escorted the ships to a dispersal point south of Newfoundland. The RCN supplied a majority of the escorts for the latter part of the voyage.

In February 1942, coincident with the arrival of U-boats off the east coast of Canada and the U.S., the organization of westbound convoys was again changed. Eastern Local escorts brought feeder convoys from various U.K. ports to Oversay, the collection point, where transatlantic convoys were taken over by mid-ocean escort groups based at Londonderry or Liverpool. These in turn would hand over their convoys to Western Local escort groups off Newfoundland, then proceed to St. John's. The Western Local escort took the convoy to Halifax or later, to New York. This pattern continued until the end of the war.

Eastbound Convoys - Eastbound convoys followed the same general pattern. HX convoys were at first provided with an ocean escort of an RN armed merchant cruiser or, occasionally, a battleship. In addition, the convoys were, for the first few months of the war, escorted by RCN destroyers to 52ºW (southeast of Newfoundland). The convoys were met west of the U.K. by an escort turning homeward from an outbound ON or ONS convoy.

With the formation of the Newfoundland Force it was possible to provide continuous escort across the Atlantic. The first convoy so protected was HX.129 which left Halifax on May 27, 1941. An eastbound convoy was now provided with a local escort to 52ºW, where an escort group from St. John's took it to MOMP (Mid-Ocean Meeting Point) at 35ºW. There it was met by a group from Iceland, which escorted the convoy on its final leg to the U.K. This pattern was changed in February 1942, to a reverse version of the westbound convoy system.