HMS Tara (1918)

The Admiralty was a department of the Government of the United Kingdom responsible for the command of the Royal Navy until 1964, historically under its titular head, the Lord High Admiral – one of the Great Officers of State. For much of its history, from the early 18th century until its abolition, the role of the Lord High Admiral was almost invariably put "in commission" and exercised by the Lords Commissioner of the Admiralty, who sat on the governing Board of Admiralty, rather than by a single person. The Admiralty was replaced by the Admiralty Board in 1964, as part of the reforms that created the Ministry of Defence and its Navy Department.

The first R class were a class of 62 destroyers built between 1916 and 1917 for the Royal Navy. They were an improvement, specifically in the area of fuel economy, of the earlier Admiralty M-class destroyers. The most important difference was that the Admiralty R class had two shafts and geared turbines, compared with the three shafts and direct turbines of the Admiralty M class, but in appearance the R class could be distinguished from its predecessors by having the after 4-inch gun mounted in a bandstand. The Admiralty ordered the first two of this class of ships in May 1915. Another seventeen were ordered in July 1915, a further eight in December 1915, and a final twenty-three in March 1916.

Length overall is the maximum length of a vessel's hull measured parallel to the waterline. This length is important while docking the ship. It is the most commonly used way of expressing the size of a ship, and is also used for calculating the cost of a marina berth.

Length between perpendiculars is the length of a ship along the summer load line from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. When there is no sternpost, the centerline axis of the rudder stock is used as the aft end of the length between perpendiculars.

The beam of a ship is its width at its widest point. The maximum beam (BMAX) is the distance between planes passing through the outer extremities of the ship, beam of the hull (BH) only includes permanently fixed parts of the hull, and beam at waterline (BWL) is the maximum width where the hull intersects the surface of the water.

The draft or draught of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel). The draught of the vessel is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if deployed. Draft determines the minimum depth of water a ship or boat can safely navigate. The related term air draft is the maximum height of any part of the vessel above the water.

The displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into weight. Traditionally, various measurement rules have been in use, giving various measures in long tons. Today, tonnes are more commonly used.

John Brown and Company of Clydebank was a Scottish marine engineering and shipbuilding firm. It built many notable and world-famous ships including RMS Lusitania, RMS Aquitania, HMS Hood, HMS Repulse, RMS Queen Mary, RMS Queen Elizabeth and the Queen Elizabeth 2.

The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.

The kilometre per hour is a unit of speed, expressing the number of kilometres travelled in one hour.

Miles per hour is a British imperial and United States customary unit of speed expressing the number of miles travelled in one hour. It is used in the United Kingdom, the United States, and a number of smaller countries, most of which are UK or US territories, or have close historical ties with the UK or US.

Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship.

Dalmuir is an area nine miles northwest of Glasgow, Scotland, on the western side of Clydebank, and part of West Dunbartonshire Council Area. The name is a lowland Scots derivation of the Gaelic meaning Big Field. The area was originally two separate villages with Dalmuir Shore joining with Clydebank in 1886 and Dalmuir Village in 1906, during a period of rapid industrialization and expansion. Dalmuir is bounded by the village of Old Kilpatrick to the west, the Mountblow and Parkhall housing schemes to the north, and the Clydebank town centre area to the east. To the south is the River Clyde.

Ceremonial ship launching involves the performance of ceremonies associated with the process of transferring a vessel to the water. It is a nautical tradition in many cultures, dating back thousands of years, to accompany the physical process with ceremonies which have been observed as public celebration and a solemn blessing, usually but not always, in association with the launch itself.

HMS Tactician was an S-class destroyer, which served with the Royal Navy. Launched on 7 August 1918, the vessel entered service at the closing of the First World War. The ship joined the Fourteenth Destroyer Flotilla of the Grand Fleet but was placed in Reserve at Nore in 1919. Tactician deteriorated over the following years and was sold to be broken up on 5 February 1931 following the signing of the London Naval Treaty that limited the amount of destroyer tonnage that the Navy could retain.

HMAS Tasmania (H25) was an Admiralty S class destroyer of the Royal Australian Navy (RAN). Built for the Royal Navy during World War I, the ship was not completed until 1919, and spent a year commissioned but not operational in British service before being transferred to the RAN at the start of 1920. The destroyer's career was uneventful, with almost all of it spent in Australian waters. Tasmania was decommissioned in 1930, and was sold for ship breaking in 1937.

The Grand Fleet was the main battlefleet of the Royal Navy during the First World War. It was established in August 1914 and disbanded in April 1919. Its main base was Scapa Flow in the Orkney Islands.

The Armistice of 11 November 1918 was the armistice signed at Le Francport near Compiègne that ended fighting on land, sea, and air in World War I between the Entente and their last remaining opponent, Germany. Previous armistices had been agreed with Bulgaria, the Ottoman Empire and Austria-Hungary. It was concluded after the German government sent a message to American president Woodrow Wilson to negotiate terms on the basis of a recent speech of his and the earlier declared "Fourteen Points", which later became the basis of the German surrender at the Paris Peace Conference, which took place the following year.

HMS Vernon was a shore establishment or "stone frigate" of the Royal Navy in Portsmouth. Vernon was established on 26 April 1876 as the Royal Navy's Torpedo Branch also known as the Torpedo School, named after the ship HMS Vernon which served as part of its floating base. After the First World War, HMS Vernon moved ashore, taking over the Gunwharf site, where it continued to operate until 1 April 1996, when the various elements comprising the establishment were split up and moved to different commands.

His Majesty's Naval Base, Portsmouth is one of three operating bases in the United Kingdom for the Royal Navy. Portsmouth Naval Base is part of the city of Portsmouth; it is located on the eastern shore of Portsmouth Harbour, north of the Solent and the Isle of Wight. Until the early 1970s, it was officially known as Portsmouth Royal Dockyard ; thereafter the term 'Naval Base' gained currency, acknowledging a greater focus on personnel and support elements alongside the traditional emphasis on building, repairing and maintaining ships. In 1984 Portsmouth's Royal Dockyard function was downgraded and it was formally renamed the 'Fleet Maintenance and Repair Organisation' (FMRO). The FMRO was privatized in 1998, and for a time, shipbuilding, in the form of block construction, returned. Around 2000, the designation HMS Nelson was extended to cover the entire base.

HMS Stronghold was an S-class destroyer, which served with the Royal Navy during the Second World War. The ship was one of the first vehicles to deploy an unmanned aircraft. Launched on 6 May 1919, the destroyer was fitted with a simple catapult in 1924, which used a bag of sand as a weight, and launched the RAE 1921 Target, an early form of unmanned aircraft. A more sophisticated cordite catapult was fitted in 1927 and used to launch the more advanced RAE Larynx. In total, more than twenty test flights were undertaken before the catapult was removed. The destroyer was subsequently fitted out as a minelayer. At the start of the Second World War, the destroyer was based in Singapore. Stronghold helped to rescue the Supermarine Walrus from the battlecruiser Repulse, which had been sunk by the Japanese, in 1941 and, the following year, towed the destroyer Vendetta on the first part of the Royal Australian Navy vessel's journey to Fremantle. On 2 March 1942, the vessel was spotted by a Japanese reconnaissance seaplane and attacked by the heavy cruiser Maya, along with the two escorting destroyers Arashi and Nowaki. Heavily outgunned, the destroyer was sunk with the loss of nine officers and sixty-one ratings.