Battle of the Atlantic

• The British steamer Adelaide Star (11,000) is seized in Copenhagen and renamed Seeburg for German use. Also seized in Copenhagen at the same time is the Icelandic steamer Gullfoss (1414t).
• The British destroyer Glowworm engages in indecisive action with the German destroyer Arnim 80 miles west of Fro Havet. The German heavy cruiser Admiral Hipper, answering Arnim's call for assistance, mortally damages the Glowworm. 9 officers and 110 sailors are lost while 38 of the crew are rescued and taken prisoner.

  British Destroyer Glowworm Under Fire

• The Polish submarine Orzel intercept the German transport Rio De Janeiro (5261t) Lillesand. The crew is ordered into lifeboats and the transport is sunk. The crew is picked up by the Norwegian destroyers Odin and Gyller.
• The British submarine Trident stops the German tanker Posidonia (8036t) in the Northern Skagerrak. The crew scuttles the tanker as they abandon ship. The tanker is salvage in June, however, and renamed Stedingen.
• The Greek steamer Okeania (4843t) sinks on a mine in the North Sea with the loss of 1 crewmen. The British destroyer Boadicea picks up 20 survivors and the Dutch steamer Beverland picks up the rest.

Norway

British destroyers begin laying mines in Norwegian territorial waters southwest of Narvik (Operation Wilfred). This action is taken to prevent the passage of German ships and the transit of Swedish iron orre to Germany. Right away Norway protests this operation.

Early in the morning the British destroyer Glowworm, after separating from her group searching for a man overboard, meets part of the German force bound for Narvik off Trondheim Fiord. After ramming the heavy cruiser Admiral Hipper, Glowworm is sunk. About midday the German transport Rio de Janeiro is torpedoed by the Polish submarine Orzel in the Skaggerak off Lillesand, southern Norway. Some 80 horses and 150 men, including 97 Luftwaffe Flak troops, drown. There are 183 survivors as many German soldiers are rescued by Norwegian fishing boats. Although this makes it clear that the German invasion force is already at sea the Norwegian authorities only alert the coastal forces in the evening.

During an evening meeting of the Council of Ministers, the Chief of Staff of the army, Col Rasmus Hatledal, informs the Defense Ministry that all officers of the general staff have assumed their posts. A decision is made on a more secret mobilization of 5 bdes in southern Norway.

The British naval forces at sea are of course alerted, but are not kept up to date with all the information available to London and are, therefore, deployed too far out to sea to hope for interceptions of a landing force. Instead they guard against a raid out toward the Atlantic. The troops embarking at Rosyth for the Anglo-French expedition to Narvik are sent back onshore and their cruiser transports sail. In fact these troops could easily have reached their objectives before the German landings, or at least have been on hand for an attempt on Narvik early in the campaign when this would have been most worthwhile.