 After completing a training for u-boat commanders beginning on 20 April 1942 he was assigned to on 5 May 1942 and became her commander on 12 June 1942.As the commander of "U-185", Maus led three missions in the Atlantic Ocean, where he managed to sink 9 ships with killing altogether 172 men, damage one ship with 6,840 GRT and shoot down two Allied aircraft.On 11 August 1943 the German submarine was attacked and heavily damaged by a US Navy Lockheed Ventura aircraft flown by Thomas D. Davies.