British home army in the First World War bridge between Tilbury and Gravesend. There were fears that a German fleet protected by mines and submarines could land a 100,000-strong force before the British Grand Fleet could steam the south from its base at Scapa Flow. To counter this threat, the Admiralty redeployed pre-dreadnought battleships and submarines closer to vulnerable ports, expanded the coastwatch and increased patrolling of the North Sea. In October, Churchill responded to Kitchener's call for the Royal Navy to take more specific precautions against invasion by insisting that the role of the Grand Fleet was to eliminate an invader's covering fleet rather than defeat the
Naval warfare of World War I Fleet defended the port of Sulina throughout the second half of 1916, causing the sinking of one German submarine. Its minelayer also defended the Danube Delta from inland, leading to the sinking of one Austro-Hungarian Danube monitor. (See also Romanian Black Sea Fleet during World War I) When Bulgaria entered World War I in 1915, its navy consisted mainly of a French-built torpedo gunboat called "Nadezhda" and six torpedo boats. It mainly engaged in mine warfare actions in the Black Sea against the Russian Black Sea Fleet and allowed the Germans to station two U-boats at Varna, one of which