 He was fascinated by submarines, and in 1908 seized the opportunity to be transferred to the navy's newly formed submarine arm, or "U-boot-Waffe", receiving promotion to "Linienschiffsleutnant" (ship-of-the-line lieutenant, or lieutenant) that November.In 1910 he was given command of the newly constructed , which was launched by his wife, the former Agatha Whitehead.He commanded "U-6" until 1913.