HMAS Australia (1911) fighter—and operated them until the end of the war. The 2nd BCS again supported minelayers in the North Sea between 25–26 June and 29–30 July. During September and October, "Australia" and the 2nd BCS supervised and protected minelaying operations north of Orkney. When the armistice with Germany was signed on 11 November 1918 to end World War I, one of the conditions was that the German High Seas Fleet was to be interred at Scapa Flow. The German fleet crossed the North Sea, and on 21 November, the British Grand Fleet sailed out to meet it; "Australia" led the port
Naval warfare of World War I came under Bulgarian control in 1916 as "Podvodnik No. 18". Russian mines sank one Bulgarian torpedo boat and damaged one more during the war. In the Baltic Sea, Germany and Russia were the main combatants, with a number of British submarines sailing through the Kattegat to assist the Russians. With the German fleet larger and more modern (many High Seas Fleet ships could easily be deployed to the Baltic when the North Sea was quiet), the Russians played a mainly defensive role, at most attacking convoys between Germany and Sweden. A major coup for the Allied forces occurred on August