Battle of the Atlantic. Developing a taste for small fry, U-19 sinks two more unescorted Danish steamers in the Moray Firth, Scotland. SS Viking is sunk at 5 AM (15 dead, 2 survivors) and SS Bothal is sunk at 5.15 (15 lives lost, 5 survivors).
U-22 departs Wilhelmshaven and is lost shortly thereafter (all 27 hands lost), failing to respond to orders on March 22, 26, 27.
Off the coast of Holland, British bombers sink the converted steamer Altenfels now known as German Sperrbrecher 12 (path-clearing ship, designed to detonate minefields).