7. The wolfpacks overwhelmed escorts of slow convoys in October, 1940
On October 5, convoy SC7 formed off Nova Scotia bound for Liverpool and ports in Scotland. The 35 ships included vessels from Greece, Norway, the Netherlands, Sweden, and Great Britain. A single British sloop served as the escort for the crossing, until it met another escort off the Western Approaches. Bad weather forced many ships to scatter six days out, and several were then sighted and sunk by U-boats. On October 17, three more escorts joined the remains of the convoy, which was nonetheless attacked by German submarines, with several more ships lost. The following day two additional escorts arrived but the Germans pressed their attacks.
On the night of October 18, a five U-boat wolfpack attacked the convoy, sinking several more ships, and attacks continued the following day. The escorts were simply overwhelmed. The Germans finally broke off the attacks, after sinking 20 of the 35 ships which had departed Canada. They carried badly needed food, lumber, steel, fuel oil, iron ore, and finished products such as trucks. Nearly 80,000 gross tons of shipping was lost through the U-boat attacks. It was, from the German point of view, the most successful coordinated U-boat attack of the war. For the British it was an unmitigated disaster, a loss of shipping and materiel ill-afforded.