Convoy PQ 6

Convoy PQ 6 (8−20/23 December 1941) was the seventh of the Arctic convoys of World War II by which the Western Allies supplied military equipment, weapons and raw materials to the Soviet Union after the German invasion on 22 June 1941. The convoy sailed from Hvalfjörður on the western coast of Iceland, on 8 December 1941.

After a storm early in the voyage there were several calm days but the temperature plunged and the crews of all ships had to work hard removing ice from their ships' superstructures. As the convoy approached the entrance to the White Sea, the Eastern local escort, of two British minesweepers, encountered four German destroyers out minelaying. One of the minesweepers was damaged; a cruiser with two Soviet destroyers put to sea from Murmansk but the German destroyers escaped.

Most of the convoy arrived at Molotovsk on 23 December but two ships made port at Murmansk on 20 December after the ships and Soviet Hurricanes chased off two Luftwaffe bombers that had attacked the freighter Dekabrist. The ships at Molotovsk were iced in for the winter in very difficult circumstances.

Between Greenland and Norway are some of the most stormy waters of the world's oceans, 890 mi (1,440 km) of water under gales full of snow, sleet and hail. Around the North Cape and the Barents Sea the sea temperature rarely rises about 4° Celsius and a man in the water would probably die unless rescued immediately. The cold water and air made spray freeze on the superstructure of ships, which had to be removed quickly to avoid the ship becoming top-heavy. The cold Arctic water is met by the Gulf Stream, warm water from the Gulf of Mexico, which becomes the North Atlantic Drift. Arriving at the south-west of England, the drift moves between Scotland and Iceland.

North of Norway the drift splits, one stream of the North Atlantic Drift goes north of Bear Island to Svalbard and the southern stream follows the coast of Murmansk into the Barents Sea. The mingling of cold Arctic water and warmer water of higher salinity generates thick banks of fog for convoys to hide in but the waters drastically reduce the effectiveness of Asdic as U-boats moved in waters of differing temperatures and density. The phenomenon is at its most disruptive of submarine detection near the Kola Inlet. In winter, polar ice can form as far south as 50 mi (80 km) of the North Cape forcing ships closer to Luftwaffe air bases or being able to sail further out to sea in summer when the ice can recede northwards as far as Svalbard. The region is in perpetual darkness in winter and permanent daylight in the summer which makes air reconnaissance almost impossible or easy.

A convoy was defined as at least one merchant ship sailing under the protection of at least one warship. At first the British had intended to run convoys to Russia on a forty-day cycle (the number of days between convoy departures) during the winter of 1941–1942 but this was shortened to a ten-day cycle. The round trip to Murmansk for warships was three weeks and each convoy needed a cruiser and two destroyers, which severely depleted the Home Fleet. Convoys left port and rendezvoused with the escorts at sea. A cruiser provided distant cover from a position to the west of Bear Island. Air support was limited to 330 Squadron and 269 Squadron, RAF Coastal Command from Iceland, with some help from anti-submarine patrols from Sullom Voe, in Shetland, along the coast of Norway. Anti-submarine trawlers escorted the convoys on the first part of the outbound journey. Built for Arctic conditions, the trawlers were coal-burning ships with sufficient endurance. The trawlers were commanded by their peacetime crews and captains with the rank of Skipper, Royal Naval Reserve (RNR), who were used to Arctic conditions, supplemented by anti-submarine specialists of the Royal Naval Volunteer Reserve (RNVR). British minesweepers based at Arkhangelsk met the convoys to join the escort for the remainder of the voyage.

By late 1941, the convoy system used in the Atlantic had been established on the Arctic run; a convoy commodore briefed the ships' masters and signals officers on arrangements for the management of the convoy, that sailed in a formation of long rows of short columns. The commodore was usually a retired naval officer or from the Royal Naval Reserve, his merchant ship flew a white pendant with a blue cross. The commodore was assisted by a Naval signals party of four men, who used lamps, semaphore flags and telescopes to pass signals in code. Codebooks were carried in a weighted bag which was to be dumped overboard to prevent capture. In large convoys, the commodore had a vice- and rear-commodore with whom he directed the speed, course and zig-zagging of the merchant ships and liaised with the escort commander.

In October 1941, the Prime Minister, Winston Churchill, had promised an Arctic convoy to the USSR every ten days. The unloading capacity of Arkhangelsk was 300,000 long tons (300,000 t), Vladivostok (Pacific Route) 140,000 long tons (140,000 t) and 60,000 long tons (61,000 t) in the Persian Gulf (for the Persian Corridor route) ports. The first convoy was due at Murmansk around 12 October and the next convoy was to depart Iceland on 22 October. A motley of British, Allied and neutral shipping, loaded with military stores and raw materials for the Soviet war effort would be assembled at Hvalfjörður (Hvalfiord) in Iceland, convenient for ships from both sides of the Atlantic. In winter, due to the polar ice expanding southwards, the convoy route ran closer to Norway. The voyage was between 1,400 and 2,000 nmi (2,600 and 3,700 km; 1,600 and 2,300 mi) each way, taking at least three weeks for a round trip.