Order of battle for Convoy SC 7

Convoy SC 7 was the seventh of the SC convoys, bound from Sydney, Nova Scotia across the North Atlantic to British ports, mainly Liverpool.^[1] They were called SC as their departure point was designated Sydney, Cape Breton to avoid confusion with Sydney in Australia.^[2] The convoys formed part of the battle of the Atlantic during the Second World War. Large numbers of merchant ships travelled with naval escorts to protect against U-boat attacks. Th convoys were often slow, the merchantmen often only being capable of a speed of around 8 kn (15 km/h; 9.2 mph) and so were particularly vulnerable to attack.^[2] This problem was exacerbated by a shortage of suitable escorts from either the Royal Canadian Navy or the Royal Navy early in the war.^[3]

Convoy SC 7 left Sydney on 5 October 1940, consisting of 36 freighters initially escorted by the Canadian armed yacht HMCS Elk and the British sloop HMS Scarborough.^[4] Having seen the convoy out of Canadian waters, Elk turned back on 7 October, leaving the convoy to spend three-quarters of the crossing escorted by Scarborough.^[4] SS Winona had developed engine problems and also turned back.^[4] The crossing was uneventful, the only casualty being SS Trevisa, which straggled behind the convoy and was torpedoed and sunk near Rockall on 16 October by U-124.^[5]

The main convoy was spotted the following day by U-38, which sank SS Aenos.^[6] Further sporadic attacks continued that day and the following, despite the arrival of the sloop HMS Fowey and the corvette HMS Bluebell. The night of 18/19 October saw the use of the wolf pack tactic by the U-boats. Five U-boats; U-46, U-99, U-100, U-101 and U-123 attacked together, overwhelming the escorts, despite being reinforced by HMS Leith and Heartsease.^[7] They sank 16 ships in a six-hours, bringing the total to twenty freighters sunk and a total tonnage lost of 79,592 gross registered tons. The U-boats only broke off their attacks to intercept convoy HX 79, which had arrived in the area. They went on to sink a further 12 ships from this convoy, for a total of 28 ships sunk on 18/19 October, making this the deadliest two days of the battle of the Atlantic.^[7] The surviving merchant ships were gathered up by the remaining escorts and brought into port several days later.