Karl Doenitz was born in Berlin-Grenau on 16th September, 1891. He enlisted as a sea cadet in 1910 and after naval training was commissioned as an officer in the German Navy in 1913.
During the First World War Doenitz served on a cruiser in the Mediterranean before being transferred to submarines in October 1916. He was captured on 4th October 1918 and remained a prisoner of war until July 1919.
Doenitz remained in the German Navy and in 1935 was put in charge of the new U-Boats being developed. However he clashed with Hermann Goering who was unwilling to supply the necessary capital to spend on the navy. Doenitz said that he needed 1,000 submarines to win any future war with Britain but by 1939 he had only 57.
At the beginning of the war the German Navy was equipped with the 750-ton Type VII U-boat. These proved too small for Atlantic operations and larger long-range types were later introduced. Doenitz developed the idea of fighting in wolf packs. Between 1940 and 1943 U-boats took a heavy toll of Allied shipping in the Atlantic, Arctic and the Mediterranean.
The Allies gradually began to introduce successful anti-submarine strategies. This included the convoy system, long-range aircraft patrols, improved antisubmarine detectors and depth charges. By May 1943 German U-Boats were forced to withdraw from the Atlantic.
Doenitz gave permission for a radically improved U-boat to be built in 1944. Working closely with Albert Speer, the Minister of Armaments, Germany were producing 42 of these all-electric boats a month by 1945. However, they were too late to make an impact on the outcome of the Second World War.
Adolf Hitler selected Doenitz to become head of state after his suicide on 30th April, 1945. After forming a new government he negotiated Germany's surrender on 8th May.
At the Nuremberg War Crimes Trial Doenitz was found guilty of war crimes and was sentenced to ten years in prison. After his release in October, 1956, he wrote his autobiography, Memoirs: Ten Years and Twenty Days (1959).
Karl Doenitz died on 24th December, 1980.