Karl Dönitz

Donitz was the commander of the U-Boat arm of the German Navy during the Second World War, having served as a U-Boat captain during the First World War. Upon Hitler's suicide, he became Reichsfuhrer of the collapsing Nazi state, and headed the shadowy German government that subsisted for several weeks at Flensburg following the German surrender. At the Nuremberg Trials he was sentenced to ten years imprisonment for war crimes, largely related to his policy of unrestricted submarine warfare.