On this day, 6th March, 1941, during the Second World War, the Battle of the Atlantic had begun. And, boy what a battle it was...
It was a long struggle for control of the seas fought between Britain and Germany who both sought to blockade one another in order to hamper and take charge of vital shipping routes. After the fall of Europe, the main supply route was between North America and the UK across the North Atlantic.
In Britain, the pressure was on to protect convoys of merchant ships and the supply of food, transport of raw materials, munitions, and men, to maintain the nation’s security and to project power across the globe. The UK was very dependent on imported goods and required more than a million tons of imported material per week in order to be able to survive and fight.
Sensing the possible disastorous consequences, Winston Churchill made his famous memorandum on 6th March and detailed a set of measures to protect the merchant ships coming to Britain. He also introduced the name 'The Battle of the Atlantic', which has also been called the "longest, largest, and most complex" naval battle in history. The campaign started immediately after the European war began, and lasted six years. It involved thousands of ships in more than 100 convoy battles and perhaps 1,000 single-ship encounters, in a theatre covering thousands of square miles of ocean.
Over the course of the battle, thousands of merchant ships and tens of thousands of lives were lost. The situation changed constantly, with one side or the other gaining advantage, as new weapons, tactics, counter-measures, and equipment were developed by both sides. The Allies gradually gained the upper hand, overcoming German surface raiders by the end of 1942 and defeating the U-boats by mid-1943, though losses to U-boats continued to war's end.
As a struggle, the Battle of the Atlantic was a very crucial combat of World War II and was pivotal to the success of the allied side.
The Germans failed to stop the flow of strategic supplies to Britain. This failure resulted in the build-up of troops and supplies needed for the D-Day landings. The defeat of the U-boat was a necessary precursor for accumulation of Allied troops and supplies to ensure Germany's defeat.
Victory was achieved at a huge cost: between 1939 and 1945, 3,500 Allied merchant ships (totalling 14.5 million gross tons) and 175 Allied warships were sunk and some 72,200 Allied naval and merchant seamen lost their lives. The Germans lost 783 U-boats and approximately 30,000 sailors killed, three-quarters of Germany's 40,000-man U-boat fleet.
It was the successful protection of this vital sea corridor by British and allied ships from the German surface and U-boat threat that led to success in North Africa, at D-Day and ultimately resulted in the fall of Germany.
After the war Winston Churchill also said: "The only thing that ever really frightened me during the war was the U-boat peril."
Interested in researching your ancestors and history?
Perhaps you or a member of your family served on one of the warships? Find out more about your ancestors by searching our war records via the Forces War Records site, or comment below and tell us about your military links.
You can find out more about World War II by looking at our historic documents library where we have a publication about the famous battle: The Battle of the Atlantic.