Battle of the Atlantic

• Adm Dönitz attempts his first 'wolf pack' deployment of U-boats, but without success. In the Orkneys, Günther Prien, with masterly navigational skill, threads his way throught the boom and net defenses to enter Scapa Flow. Amazingly he remains undetected although surfaces until he reaches his first targets.
• U-40 is mined and sinks in the Dover Strait in the Folkestone-Gris Nez deep minefield. 38 crew are lost with British destroyers Brazen and Boreas picking up 3 survivors.
• U-42 damages the British steamer Stonepool (4802t), but is counterattacked by the British destroyers Imogen and Ilex. The submarine sinks 290 miles southwest of Fastnet. 25 of the crew are lost, but the Ilex pics up 17 survivors.
• U-48 sinks the French steamer Louisiane (6903t) from the dispersed convoy OB-17 240 miles southwest of Fastnet losing 1 crewman. The survivors are picked up by the British destroyer Imogen.
• The Norwegian steamer Gressholm (619t) is sunk by a mine 90 miles northwest of Texel losing 3 or her crew. 8 survivors are rescued by the Finnish steamer Emmi