[2] The ships departed Liverpool on 4 September 1942[3] and were met at noon on 5 September[1] by the Royal Canadian Navy Mid-Ocean Escort Force Group C-4 consisting of the River-class destroyer Ottawa and the Town-class destroyer St. Croix with the Flower-class corvettes Amherst, Arvida, Sherbrooke, and Celandine.

[5] As western Atlantic coastal convoys brought an end to the second happy time, Admiral Karl Dönitz, the Befehlshaber der U-Boote (BdU) or commander in chief of U-Boats, shifted focus to the mid-Atlantic to avoid aircraft patrols.

[8] A coordinated night attack on the convoy began with U-659 torpedoing the British tanker Empire Oil on the evening of 10 September.

[2][12][13] Sherbrooke remained astern of the convoy aiding the ships torpedoed by U-96, and rescued all but one of the crew of the sinking Svene and Elisabeth van Belgie.

U-584 torpedoed the Norwegian Hindanger in a submerged daylight attack while St. Croix investigated a visual sighting six miles distant.

120 Squadron RAF prevented further daylight attacks on 11 September[15] but U-96 sank a 415-ton Portuguese sailing trawler by gunfire in the vicinity of the convoy.

[2][9][17] Excellent visibility on 12 September allowed a close forward screen of four escorts to discourage U-boats sighted up to 7 miles away.

U-594 sank the straggling Stone Street[12] as the convoy came within range of Canadian Canso patrol bombers from Botland, Newfoundland on 13 September.