Ultra and the Battle of the Atlantic – The True Story
By Tim D. Lyon
“The Battle of the Atlantic was the dominating factor all throughout the war. Battles might be won or lost, enterprises might succeed or miscarry, territories might be gained or quitted, but dominating all our power to carry on the war, or even keep ourselves alive, lay our mastery of the ocean routes and the free approach and entry to our ports.” Winston Churchill
The Battle of the Atlantic was the longest battle of the Second World War, lasting from 3rd September 1939 to 10 thMay 1945. The German attack on merchant shipping in the Atlantic was countered partly by code-breaking intelligence known as Ultra. It was actually known as Special
Intelligence, Ultra was merely a security classification. However, this paper will refer to it as Ultra as this term has come into common usage. And in this paper the term Ultra only applies to the products of Bletchley Park, ie decrypted messages in the German Enigma Cipher. The Enigma machine was one of the best of the new electromechanical cipher machines produced for the commercial market in the 1920s. All three services in the German Wehrmacht, the Army, the Luftwaffe and the Navy adopted the Enigma machine.
Early in 1939 Britain’s secret service set up Station X at Bletchley Park 50 miles north of London, for the purpose of intercepting the German’s Enigma signals (more than 1,000 daily in 1939) and controlling the distribution of the resultant ‘Ultra’ secret intelligence. Some of the German Air Force Enigma ciphers were cracked as early as April 1940, and the Army ones not long afterwards. However, the German Naval Enigma would not be cracked until the war was 21 months old.
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