Admiralty
It evolved from *Admiralty Navy War Council, (1909–1912) which in turn became the Admiralty War Staff, (1912–1917) before finally becoming the Admiralty Naval Staff in 1917. It was the former senior command, operational planning, policy and strategy department within the British Admiralty. It was established in 1917 and existed until 1964 when the department of the Admiralty was abolished, and the staff departments function continued within the Navy Department of the Ministry of Defence until 1971 when its functions became part of the new Naval Staff, Navy Department of the Ministry of Defence.
Armed yacht
Before the outbreak of war in Europe, there had been much discussion in the United Kingdom of a wartime role for privately owned motor and steam yachts and smaller power boats. This led to Admiral Sir Frederick Inglefield forming a Motor Boat Reserve Committee in 1912 to consider whether this would be useful and how it could be achieved. In early 1914 the Admiralty created a Motor Boat Reserve with experienced volunteers from various yacht clubs. At the start of the war in August 1914, the reserve was activated under the title Royal Naval Motor Boat Reserve (RNMBR). Eventually, the RNMBR was incorporated into the Auxiliary Patrol and its crews into the Royal Naval Volunteer Reserve (RNVR). By December 1914, each sea area of the British Isles was allocated a dedicated unit of the Auxiliary Patrol, typically comprising six armed trawlers or drifters and a single armed yacht, together with smaller motor boats, with the roles of harbour defence, mine clearance and anti-submarine patrolling. The crews were augmented by volunteers from all over the British Empire. By 1917, there were 150 patrol units, each led by an armed yacht, usually equipped with radio. In the course of the war, a total of 159 motor yachts were hired by the Admiralty, some serving as far away as the Dardanelles. The British armed yacht HMS "Lorna" destroyed the German U-Boat SM UB-74 with depth charges off Portland Bill in May 1918. A number of motor yachts operated as patrol boats in the waters of British Dominions and colonies, including the "Nusa", a German yacht which was captured in the Solomon Islands in September 1914 and was later used by the Royal Australian Navy in their home waters.