1939 1940 1941 1942 1943 1944 1945 The Battle of the Bay of Biscay or Operation Bernau, was a naval action that took place on 28 December 1943 during the Second World War during the Atlantic campaign.

The engagement took place between two light cruisers of the Royal Navy and a force of destroyers and torpedo boats of the Kriegsmarine that had sailed to rendezvous with a blockade-runner and escort it to port.

After the supply route was closed at the start of Barbarossa and after the Japanese entry into the war, German and Italian ships were stranded in Japan and Japanese-occupied Singapore.

The ships were used as blockade-runners, sailing to ports in occupied France after mid-1940, when Germany had taken control of the European coast from Norway to the French–Spanish border.

[5] After sailing from Japan, through the Pacific and the Indian Ocean to the Cape of Good Hope, blockade-runners kept radio silence and passed rearranging points at planned times.

The vessel went into dry dock to have the hull cleaned to increase its speed and the ship underwent sea trials, sometimes incorporating the delivery of goods to Bassens or to another Biscay port.

From May 1943 decrypts of Japanese diplomatic wireless traffic revealed to the Allies that the losses of the 1942–1943 season had not deterred the Axis from making another attempt in the autumn.

[7] On 18 July the British and Portuguese reached a basing agreement for the Azores, which came into force on 8 October and which had the potential to deter the Axis from trying to run the blockade.

There were five motor vessels in Japan and it was thought that if they left at fairly frequent intervals, the Allies might be distracted by the hunt for one and let another slip through their blockades.

[12] Osorno was followed by the refrigerated cargo ship (reefer) Alsterufer (2,729 GRT, code-name Trave, Kapitan Piatek) of the Robert M. Sloman Jr. line of Hamburg, carrying 344 long tons (350 t) of tungsten; a year's worth of consumption in the German war economy.

Allied spies reported the arrival of the first three ships at Saigon (now Ho Chi Minh City), raising the alarm.

[14] In late December 1943 a Kriegsmarine destroyer flotilla, reinforced by six large Elbing-class torpedo boats, was ordered to the Bay of Biscay to escort the blockade runners Osorno and Alsterufer, which were carrying vital cargo from Japan (Operation Bernau).

[18] Just after noon the torpedo boats turned east, astern of the northernmost destroyers, taking station on their port side.

[15] The German flotillas did not know that during the previous afternoon a B-24 Liberator bomber of 311 (Czechoslovak) Squadron had attacked and set Alsterufer on fire.

[17] Captain Charles Clark on Glasgow, assuming that he had been reported, turned north-east, working around the position of the German ships to intercept them.

The sea was becoming rougher and the wind had increased to 30 kn (56 km/h; 35 mph), making sailing difficult for the destroyers and torpedo boats.

[16] At about 14:05, a German shell hit Glasgow, exploding in 'A' boiler room, killing two members of the port pom-pom crew and wounding six others; Enterprise was straddled by near misses.

[17] The German force split and Glasgow reversed course at 14:35 to chase the northerly group of destroyers; Enterprise had already altered course to the west to head them off.

[17] Glasgow concentrated on T25, which received hits near the aft torpedo tubes, the Flakvierling and the 3.7 cm flak platforms, which killed or wounded their crews.

[16] Morale in the Kriegsmarine was already depressed with the news that the battleship Scharnhorst had been sunk at the Battle of the North Cape, two days before the losses in the Bay of Biscay.

[20] In daylight the stability of the larger cruisers as gun platforms in stormy seas, gave them an advantage and the long-range torpedo attacks of the Germans were ineffective.