Convoy PQ 17
Convoy PQ 17 was an Allied Arctic convoy during the Second World War. On 27 June 1942, the ships sailed from Hvalfjörður, Iceland, for the port of Arkhangelsk in the Soviet Union. The convoy was located by German forces on 1 July, shadowed and attacked.
The First Sea Lord, Admiral Sir Dudley Pound, acting on information that German ships, including, were moving to intercept, ordered the covering force, based on the Allied battleships and away from the convoy and told the convoy to scatter. Because of vacillation by Oberkommando der Wehrmacht, the Tirpitz raid never materialised. The convoy was the first large joint Anglo–American naval operation under British command; in Churchill's view this encouraged a more careful approach to fleet movements.
As the close escort and the covering cruiser forces withdrew westwards to intercept the German raiders, the merchant ships were left without escorts. The freighters were attacked by Luftwaffe aircraft and U-boats and of the 35 ships, only eleven reached their destination, delivering of cargo. The convoy disaster demonstrated the difficulty of passing adequate supplies through the Arctic, especially during the summer, with the midnight sun. The German success was possible through German signals intelligence and cryptological analysis.
Background
Lend-lease
After Operation Barbarossa, the German invasion of the USSR, began on 22 June 1941, the UK and USSR signed an agreement in July that they would "render each other assistance and support of all kinds in the present war against Hitlerite Germany". Before September 1941 the British had dispatched 450 aircraft, of rubber, 3,000,000 pairs of boots and stocks of tin, aluminium, jute, lead and wool. In September British and US representatives travelled to Moscow to study Soviet requirements and their ability to meet them. The representatives of the three countries drew up a protocol in October 1941 to last until June 1942 and to agree new protocols to operate from 1 July to 30 June of each following year until the end of Lend-Lease. The protocol listed supplies, monthly rates of delivery and totals for the period.The first protocol specified the supplies to be sent but not the ships to move them. The USSR turned out to lack the ships and escorts and the British and Americans, who had made a commitment to "help with the delivery", undertook to deliver the supplies for want of an alternative. The main Soviet need in 1941 was military equipment to replace losses because, at the time of the negotiations, two large aircraft factories were being moved east from Leningrad and two more from Ukraine. It would take at least eight months to resume production, until when, aircraft output would fall from 80 to 30 aircraft per day. Britain and the US undertook to send 400 aircraft a month, at a ratio of three bombers to one fighter, 500 tanks a month and 300 Bren gun carriers. The Anglo-Americans also undertook to send of aluminium and 3,862 machine tools, with sundry raw materials, food and medical supplies.
British grand strategy
The growing German air strength in Norway and increasing losses to convoys and their escorts, led Rear-Admiral Stuart Bonham Carter, commander of the 18th Cruiser Squadron, Admiral Sir John Tovey, Commander in Chief Home Fleet and Admiral Sir Dudley Pound the First Sea Lord, the professional head of the Royal Navy, unanimously to advocate the suspension of Arctic convoys during the summer months.Bletchley Park
The British Government Code and Cypher School based at Bletchley Park housed a small industry of code-breakers and traffic analysts. By June 1941, the German Enigma machine Home Waters settings used by surface ships and U-boats could quickly be read. On 1 February 1942, the Enigma machines used in U-boats in the Atlantic and Mediterranean were changed but German ships and the U-boats in Arctic waters continued with the older Heimish. By mid-1941, British Y-stations were able to receive and read Luftwaffe W/T transmissions and give advance warning of Luftwaffe operations. In 1941, naval Headache personnel with receivers to eavesdrop on Luftwaffe wireless transmissions were embarked on warships.''B-Dienst''
The rival German Beobachtungsdienst of the Kriegsmarine ''Marinenachrichtendienst had broken several Admiralty codes and cyphers by 1939, which were used to help Kriegsmarine ships elude British forces and provide opportunities for surprise attacks. From June to August 1940, six British submarines were sunk in the Skaggerak using information gleaned from British wireless signals. In 1941, B-Dienst read signals from the Commander in Chief Western Approaches informing convoys of areas patrolled by U-boats, enabling the submarines to move into "safe" zones. B-Dienst had broken Naval Cypher No 3 in February 1942 and by March was reading up to 80 per cent of the traffic, which continued until 15 December 1943. By coincidence, the British lost access to the Shark'' cypher and had no information to send in Cypher No 3 which might compromise Ultra. In early September, Finnish Radio Intelligence deciphered a Soviet Air Force transmission which divulged the convoy itinerary, which was forwarded it to the Germans.Arctic Ocean
Between Greenland and Norway are some of the most stormy waters of the world's oceans, of water under gales full of snow, sleet and hail. The cold Arctic water was met by the Gulf Stream, warm water from the Gulf of Mexico, which became 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 bears north of Bear Island to Svalbard and a 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 reduced the effectiveness of ASDIC as U-boats moved in waters of differing temperatures and density.In winter, polar ice can form as far south as off the North Cape and in summer it can recede to Svalbard. The area is in perpetual darkness in winter and permanent daylight in the summer and can make air reconnaissance almost impossible. Around the North Cape and in the Barents Sea the sea temperature rarely rises about 4° Celsius and a man in the water will die unless rescued immediately. The cold water and air makes spray freeze on the superstructure of ships, which has to be removed quickly to avoid the ship becoming top-heavy. Conditions in U-boats were, if anything, worse the boats having to submerge in warmer water to rid the superstructure of ice. Crewmen on watch were exposed to the elements, oil lost its viscosity, nuts froze and sheared off. Heaters in the hull were too demanding of current to be run continuously.
Arctic convoys
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 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, who were used to Arctic conditions, supplemented by anti-submarine specialists of the Royal Naval Volunteer Reserve. 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 ensured that the ships' masters and signals officers attended a briefing to make arrangements for the management of the convoy, which sailed in a formation of long rows of short columns. The commodore was usually a retired naval officer or from the Royal Naval Reserve and would be aboard one of the merchant ships. The commodore was assisted by a Naval signals party of four men, who used lamps, semaphore flags and telescopes to pass signals in code. The codebooks were carried in a weighted bag which was to be dumped overboard to prevent capture. In large convoys, the commodore was assisted by vice- and rear-commodores 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, made a commitment to send a convoy to the Arctic ports of the USSR every ten days and to deliver a month from July 1942 to January 1943, followed by and another in excess of those already promised. 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 in Iceland, convenient for ships from both sides of the Atlantic.
By the end of 1941, 187 Matilda II and 249 Valentine tanks had been delivered, comprising 25 per cent of the medium-heavy tanks in the Red Army and 30 to 40 per cent of the medium-heavy tanks defending Moscow. In December 1941, 16 per cent of the fighters defending Moscow were Hawker Hurricanes and Curtiss Tomahawks from Britain; by 1 January 1942, 96 Hurricane fighters were flying in the Soviet Air Forces. The British supplied radar apparatuses, machine tools, ASDIC and other commodities. During the summer months, convoys went as far north as 75 N latitude then south into the Barents Sea and to the ports of Murmansk in the Kola Inlet and Arkhangelsk in the White Sea. In winter, due to the polar ice expanding southwards, the convoy route ran closer to Norway. The voyage was between each way, taking at least three weeks for a round trip.