HMS Cossack (F03)

Wartime modifications

Heavy losses to German air attack during the Norwegian Campaign demonstrated the ineffectiveness of the Tribals' anti-aircraft suite and the RN decided in May 1940 to replace 'X' mount with two QF 4-inch (102 mm) Mark XVI dual-purpose guns in a twin-gun mount. To better control the guns, the existing rangefinder/director was modified to accept a Type 285 gunnery radar as they became available. The number of depth charges was increased to 46 early in the war, and still more were added later.^[11] To increase the firing arcs of the AA guns, the rear funnel was shortened and the mainmast was reduced to a short pole mast.^[12]

Altmark incident

Cossack's first action was on 16 February 1940, under the command of Philip Vian. This was the Altmark Incident in Jøssingfjord, Norway which resulted in the freeing of the Admiral Graf Spee's prisoners, who were being held aboard the supply ship Altmark, and the death of eight crew members of the German ship.

In the incident the German tanker rammed her with the stern at an angle of about 30° at the level of her bridge and drove the destroyer towards the fjord wall. The Norwegian officers present later reported that only the mass of ice piled up prevented the destroyer being crushed onto the rocky shore. The powerful engines of the destroyer made her escape from the squeeze possible.^[18] Cossack arrived at Leith on 17 February with the 299 freed prisoners.^[19] She had to be docked for her propeller and A-brackets to be checked in case they had been damaged by the fjord's thick ice. They were unharmed, but her stern plating had to be repaired where it had been bumping against Altmark.^[20]

The Norwegian government subsequently protested at Cossack's breach of Norway's neutrality and demanded the return of the British prisoners of war; the German government also protested that the incident had been a violation of international law.^[21]

Second Battle of Narvik

Cossack participated in the Second Battle of Narvik in April 1940. Entering Narvik harbour at 14.15 hrs, she engaged a stationary German destroyer Z17. Broadside on, she was hit 7 times in 2 minutes, causing serious damage & breaking her steering gear. Out of control, Cossack ran aground on the shore. When her adversary, Diether von Roeder, ran out of ammunition, she was scuttled. With temporary repairs, Cossack refloated during the night at high tide and crawled her way stern-first to Skelfjord, Lofotens, where she was patched up sufficiently to limp home. In the brief but violent harbour engagement, Cossack lost 9 killed and 21 wounded. Later that year, she was part of the force which was assigned to hunt for a German surface raider that had been reported breaking out into the North Atlantic. The force consisted of the battlecruiser Hood, the light cruiser Edinburgh, and the destroyers Electra, Echo, Escapade, and Cossack. The report turned out to be false, so after spending a week at sea, including Christmas Day, she returned to port on New Year's Eve.

Chasing Bismarck

In May 1941, she participated in the pursuit and destruction of the German battleship Bismarck. While escorting Convoy WS-8B to the Middle East, Cossack and four other destroyers broke off on 26 May, and headed towards the area where Bismarck had been reported. They found Bismarck that evening and made several torpedo attacks in the evening and into the next morning. No hits were scored, but they kept the Bismarck's gunners from getting any sleep, making it easier for the battleships to attack the Bismarck the next morning. During the battle one of Bismarck's shells sheared off Cossack's antenna.