Despite the building programme he oversaw, he believed that the war had come too soon for a successful surface challenge to the Royal Navy, as the Fleet Act of 1900 had included a seventeen-year timetable. Unable to direct naval operations from his purely administrative position, Tirpitz became a vocal spokesman for unrestricted U-boat warfare, which he felt could break the British stranglehold on Germany's sea lines of communication. While the German Navy briefly abandoned the observance of prize rules in 1915, this policy was soon reversed following the outcry over the "Lusitania" sinking. When the restrictions on the submarine war were not lifted, he fell out with the Kaiser and felt compelled to resign on 15 March 1916. He was replaced as Secretary of State of the Imperial Naval Office by Eduard von Capelle.