After U-boats had forced the British into convoys, the German Navy planned to attack them with warships. On 22 May 1941, the new battleship Bismarck set out on an Atlantic raid. Spotted near Iceland, she sank the battlecruiser Hood and headed for France, hunted by the British. Torpedo aircraft damaged her steering and on 27 May she was sunk, ending German surface operations in the Atlantic.
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Britain depended on vital supplies from North America and the Empire. These had to be transported in merchant ships across the Atlantic Ocean, where they could be attacked by German submarines (U-boats) and warships.
They were grouped into convoys escorted by warships and, if possible, aircraft. The first Atlantic convoy sailed on 2 September 1939. At first, convoys dispersed once they had passed out of range of U-boats.
Winston Churchill coined the phrase 'Battle of the Atlantic' on 6 March 1941, deliberately echoing the 'Battle of Britain' to emphasise its importance.
At first, many merchant ships were lost. The fall of France in June 1940 gave the U-boats bases on the Atlantic coast, and U-boat production increased during spring 1941, giving the Germans enough submarines to deploy groups or 'wolf packs'. However, in May the loss of the battleship Bismarck ended surface raids, and the Allies extended the convoy system right across the Atlantic. Intelligence successes allowed the Allies to route convoys away from danger, and losses finally fell.
After America entered the war, the Germans sank nearly 500 unescorted ships off the US east coast in early 1942 until the Americans introduced convoys. The wolf packs returned to the mid Atlantic. A temporary Allied inability to read their signals meant that by the end of 1942, Allied shipping was in crisis. The introduction of aircraft carriers, Very Long Range aircraft, and roving 'support groups' of warships, eventually defeated the U-boats at the end of May 1943.
A Rescue-ship in the Atlantic, March 1943, by George Plante. The first dedicated ‘rescue ships’ were added to convoys in 1941. They were usually small ships with straight sides so that it was easier to haul survivors on board. They also had to be fast so that they could catch up with the convoy again once the rescue was completed. The rescue ship shown in the painting will have little chance of carrying out a rescue this time. The ship that has been torpedoed is carrying aircraft fuel and has exploded. Its crew have little chance of survival.
The Atlantic covers over 100 million square kilometres. In such a vast space, finding a convoy was harder than finding a single ship, as there were fewer targets, and attacking U-boats could be attacked by the escorting warships. Convoys were formed into several columns of ships, with up to five ships in each column, forming a big box of up to 60 ships. Ships of roughly similar speeds sailed together.
Corvettes were based on whaling ships. They were slow and uncomfortable, but could be built very quickly in civilian shipyards. In total 267 were built, 122 of which served with the Royal Canadian Navy. As a result of the Battle of the Atlantic the RCN became the third largest navy in the world, with 373 ships and over 92,000 men and women in uniform by 1945.
Britain had very few convoy escorts and on 15 May 1940, Churchill asked President Roosevelt for 50 old American destroyers. Selling them to Britain was against US law, but eventually they were exchanged for rights to use British bases. Although old and uncomfortable, they were very useful and demonstrated Roosevelt’s desire to help. Later he ordered the US Navy to help escort convoys, months before America entered the war.
U-boats were almost defenceless against aircraft, but in 1939 only a few old types were available. Gradually modern, long-range aircraft with radar were introduced, operating across the Atlantic from Iceland and Canada, leaving only a 300-mile wide 'black pit' in mid ocean. New weapons made aircraft efficient U-boat killers, but only the arrival of Very Long Range Liberators, like this one, in 1943 finally covered the 'pit'.
A Women’s Royal Naval Service (Wren) plotter in 'The Citadel', the Western Approaches Command (WAC) Headquarters bunker underneath Derby House in Liverpool, 1944. WAC was responsible for protecting all Atlantic shipping. On this huge wall chart, Wren plotters recorded the movements of convoys, warships and U-boats, while senior officers from the Royal Navy and Royal Air Force planned the battle like a giant game of chess.
Type VII (left) and Type IX U-boats in Norway at the end of the war, 1945. The Atlantic U-boat fleet used variants of the Type VII throughout the war, although new boats were in development by 1945. The long-range Type IX 'U-cruisers' operated in the Caribbean, South Atlantic and Indian ocean. Some even sailed all the way to Japan.
John Worsley was serving as a midshipman in the Royal Naval Reserve when he made these drawings of sailors in armed merchant cruisers on convoy escort duties in the North Atlantic. In July 1943 he was appointed as one of the Royal Navy’s only two official war artists. Two months later, he was captured in the Adriatic on a mission to rescue British POWs and became a prisoner himself at Marlag POW camp at Westertimke in Germany.