ON convoys

The ON convoys were a series of North Atlantic trade convoys running Outbound from the British Isles to North America during the Battle of the Atlantic (1939-1945).

From 7 September 1939, shortly after the outbreak of World War II, OB convoys sailed from Liverpool south through St George's Channel to the open Atlantic. Off Land's End the convoy would be joined by an OA convoy from London on the River Thames via the English Channel. The combined OA/OB convoys were escorted for about four days to get beyond the range of U-boat patrols before the ships dispersed to reach their individual destinations. After the fall of France in June 1940, OA and OB convoys sailed north to join in the Western Approaches. As German aircraft, submarines, and surface ships reached further into the Atlantic, ships formerly assigned to OA/OB convoys were formed into ON convoys sailing from Liverpool via the North Channel and escorted all the way to Halifax Harbour. These convoys were sequentially numbered from ON 1 sailing on 26 July 1941 to ON 305 sailing on 27 May 1945.

From August 1942, the Mid-Ocean Escort Force of British and Canadian ships (with a few United States Coast Guard cutters) delivered ON convoys to the Royal Canadian Navy Western Local Escort Force (WLEF) off Halifax; and the WLEF escorted most convoys from ON 125 through ON 301 to New York City.

...
Wikipedia