Battle of the Atlantic · United Kingdom vs Germany
Convoys SC 7 and HX 79
16 October 1940 – 20 October 1940
A wolfpack of U-boat aces including Kretschmer and Schepke fell on the weakly escorted convoy SC 7 west of Ireland, sinking 20 of its 35 ships. The next night Prien found convoy HX 79 nearby and called the same boats onto it; twelve more ships were sunk for no loss, the high point of the U-boats' 'First Happy Time'.
Explore Convoys SC 7 and HX 79 on the interactive map · Wikipedia
Day by day
— First contact
SC 7, 35 slow ships out of Sydney, Cape Breton, has one sloop, Scarborough, for escort until Fowey and Bluebell join on the 17th. U-124 picks off the straggler Trevisa on the 16th; U-48 finds the convoy that evening and sinks Languedoc and Scoresby at about 04:00 on the 17th before Sunderlands drive her down. Doenitz orders five boats to a patrol line west of Rockall.
— The wolfpack
Leith and Heartsease join, making five escorts; U-38 sinks Carsbreck that morning. After dark U-46, U-99, U-100, U-101 and U-123 attack together from inside the columns, the first true pack attack of the war. Kretschmer alone sinks six ships. Fifteen go down before dawn on the 19th, among them the commodore's Assyrian, and the escorts, with no plan for fighting together, never get a firm contact.
— HX 79
Prien in U-47 sights HX 79 on the 19th and calls up U-46, U-48, U-100 and U-38. The convoy has eleven escorts, more than any yet, but they have never worked together and the boats attack on the surface after dark; twelve ships are sunk for no loss. SC 7's fifteen survivors are entering the North Channel.
— The reckoning
U-99 sinks the straggler Loch Lomond on the morning of the 20th, and the boats, out of torpedoes, turn for Lorient. Thirty-two ships of some 150,000 tons have gone in three nights without a U-boat scratched. The Admiralty answers with permanent escort groups, which take a year to train.
