Shelling of a British Convoy by the Germans from the French Coast, 1940, painting by Charles Pears. Coaster convoys still went through the Channel to keep the south-east supplied with coal. German coastal batteries near Calais shelled them fairly constantly after August 1940, although with very little success
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Britain depended on vital supplies of food, equipment and raw materials from overseas, notably from North America and the Empire. These goods were transported in thousands of merchant ships, which were vulnerable to attack by German submarines (U-boats). As there were not enough warships to protect thousands of individual merchant ships, they were grouped into convoys with naval escorts, making them hard to find and difficult to attack.
Merchant shipping was placed under Admiralty control on 26 August 1939, and the first convoy sailed on 2 September. Four days later, the first regular series of convoys began. Convoy FS1 – standing for Forth-Southbound – was tasked with protecting the coal supply routes along Britain’s east coast.
Following the launch of Convoy FS1, on 7 September Atlantic convoys were launched from both the Thames, coded OA, and the Mersey, OB. Once outside the U-boat danger area near the British coast, the convoys dispersed, as the smaller escorts were defenceless against the German surface raiders operating far out in the Atlantic. Homeward-bound merchant ships carrying war supplies, however, were convoyed all the way – most notably along the route from Halifax, Nova Scotia (coded HX) – and were often protected by heavy warships.
After the fall of France in June 1940, German U-boats moved to new French bases, increasing their range. As a result, convoys were extended across the Atlantic. This marked the beginning of a dangerous phase of the war, dubbed the Battle of the Atlantic by Winston Churchill. As the fighting progressed, new convoys became necessary, including routes to Malta and Russia (the ‘Arctic Convoys’). In total, 450 convoy series were run over the course of the war.
An Atlantic convoy in 1940. Most ocean convoys had six to nine columns, each with up to five ships, although the largest, HX300 (in 1944), contained 167 ships in 19 columns. Each ship’s captain was given his number and position at a conference held before sailing, and a naval commodore sailed with them to ensure that they followed instructions. Fewer columns were possible in narrow coastal waters, leading to convoys many miles in length.
The aircraft carrier HMS Courageous sinking, 17 September 1939. First Lord of the Admiralty Winston Churchill felt that convoying was too defensive a tactic, and instead preferred sweeping for U-boats using aircraft carriers and destroyers. This was not a success; Courageous was taking part in a sweep when she was sunk by U-29, and 518 men lost their lives.
Ex-American destroyers in Devonport, 1940. In 1939 the Royal Navy was desperately short of convoy escorts. On 2 September 1940, the United States agreed to exchange 50 old US Navy destroyers for access to British bases. Although welcome, the destroyers had been designed for the Pacific and were very uncomfortable in an Atlantic gale.
A Naval Control Service office, 'somewhere in England'. The Admiralty exercised control of merchant shipping through the Trade Division, which had a worldwide network of Naval Control Service officers stationed in every port used by British shipping. They were mostly retired officers or reservists, supported by a small team of Women's Royal Naval Service (‘Wren’) Boarding Officers.