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Dumaresq Island
The Dumaresq is a mechanical calculating device invented around 1902 by Lieutenant John Dumaresq of the Royal Navy. It is an analogue computer that relates vital variables of the fire control problem to the movement of one's own ship and that of a target ship. It was often used with other devices, such as a Vickers range clock, to generate range and deflection data so the gun sights of the ship could be continuously set. A number of versions of the Dumaresq were produced of increasing complexity as development proceeded. Geometric principle The dumaresq relies on sliding and rotating bars and dials to represent the motion of the two ships. Normally the motion of the ship carrying the dumaresq is represented by a metal bar running above the instrument. Below the bar is a round metal plate inscribed with a coordinate plot, and an angle scale around its outer rim. The fixed bar is mounted on a bearing that allows it to be turned to represent the direction of motion of the ship, ...
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Frederic Dreyer
Admiral Sir Frederic Charles Dreyer, (8 January 1878 – 11 December 1956) was an officer of the Royal Navy. A gunnery expert, he developed a fire control system for British warships, and served as flag captain to Admiral Sir John Jellicoe at the Battle of Jutland. He retired with the rank of admiral in 1943, having served through two world wars and having already retired once. Background and early life Frederic Dreyer was born on 8 January 1878 in the Irish town of Parsonstown (now Birr) in King's County (now County Offaly), the second son of the Danish-born astronomer John Louis Emil Dreyer who was director of the Armagh Observatory. Educated at The Royal School, Armagh, in 1891 Dreyer joined the Royal Navy and entered the Royal Naval College, Dartmouth. Royal Navy career Early years At Dartmouth Dreyer performed well in his examinations and was placed fifth in his term. He then served as a midshipman in HMS ''Anson'' (1893–1896) and HMS ''Barfleur'' (1896–1897). ...
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Mechanical Computers
A mechanical computer is a computer built from mechanical components such as levers and gears rather than electronic components. The most common examples are adding machines and mechanical counters, which use the turning of gears to increment output displays. More complex examples could carry out multiplication and division—Friden used a moving head which paused at each column—and even differential analysis. One model, the Ascota 170 accounting machine sold in the 1960s calculated square roots. Mechanical computers can be either analog, using smooth mechanisms such as curved plates or slide rules for computations; or digital, which use gears. Mechanical computers reached their zenith during World War II, when they formed the basis of complex bombsights including the Norden, as well as the similar devices for ship computations such as the US Torpedo Data Computer or British Admiralty Fire Control Table. Noteworthy are mechanical flight instruments for early spacecraft, which ...
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Military Computers
This article specifically addresses U.S. armed forces military computers and their use. History Some of the earliest computers were military computers. Military requirements for portability and ruggedness led to some of the earliest transistorized computers, such as the 1958 AN/USQ-17, the 1959 AN/MYK-1 (MOBIDIC), the 1960 M18 FADAC, and the 1962 D-17B; the earliest integrated-circuit based computer, the 1964 D-37C; as well as one of the earliest laptop computers, the 1982 Grid Compass. Military requirements for a computer small enough to fit through a submarine's hatch led to the AN/UYK-1. Construction Typically a military computer is much more robust than an industrial computer enclosure. Most electronics will be protected with a layer of conformal coating. There will be more structure inside to support the components, the plug-in cards will be individually supported and secured to assure they do not pop out of their sockets, the processor and heat sink will be secured, m ...
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British Admiralty
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 (later Navy Command). Before the Acts of Union 1707, the Office of the Admiralty and Marine Affairs administered the Royal Navy of the Kingdom of England, which merged with the Royal Scots Navy and the absorbed the responsibilities of the Lord High Admiral of the Kingdom of Scotland with the unification of the Kingdom of Gr ...
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Dreyer Fire Control Table
Admiral Sir Frederic Charles Dreyer, (8 January 1878 – 11 December 1956) was an officer of the Royal Navy. A gunnery expert, he developed a fire control system for British warships, and served as flag captain to Admiral Sir John Jellicoe at the Battle of Jutland. He retired with the rank of admiral in 1943, having served through two world wars and having already retired once. Background and early life Frederic Dreyer was born on 8 January 1878 in the Irish town of Parsonstown (now Birr) in King's County (now County Offaly), the second son of the Danish-born astronomer John Louis Emil Dreyer who was director of the Armagh Observatory. Educated at The Royal School, Armagh, in 1891 Dreyer joined the Royal Navy and entered the Royal Naval College, Dartmouth. Royal Navy career Early years At Dartmouth Dreyer performed well in his examinations and was placed fifth in his term. He then served as a midshipman in HMS ''Anson'' (1893–1896) and HMS ''Barfleur'' (1896–1897). ...
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Admiralty Fire Control Table
Admiralty Fire Control Table in the transmitting station of .The Admiralty Fire Control Table (A.F.C.T.) was an electromechanical analogue computer fire-control system that calculated the correct elevation and deflection of the main armament of a Royal Navy cruiser or battleship, so that the shells fired would strike a surface target. The AFCT MK 1 was fitted to and in the early 1920s, while the battleships , , and , and the battlecruiser , received Mk VII tables in the late 1930s. Battleships of the ''King George V'' class received a Mk IX table, while received the final variant, the Mk X. The AFCT was the successor to the Dreyer tables, developed by Captain (later Admiral) Frederic Charles Dreyer, and the Argo Clock, developed by Arthur Pollen, and received developmental input from both men. The Admiralty Fire Control Clock (AFCC) was a simplified version of the AFCT and was used for the local control of main armament and primary control of secondary armament of battleships ...
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Dreyer Table
Admiral Sir Frederic Charles Dreyer, (8 January 1878 – 11 December 1956) was an officer of the Royal Navy. A gunnery expert, he developed a fire control system for British warships, and served as flag captain to Admiral Sir John Jellicoe at the Battle of Jutland. He retired with the rank of admiral in 1943, having served through two world wars and having already retired once. Background and early life Frederic Dreyer was born on 8 January 1878 in the Irish town of Parsonstown (now Birr) in King's County (now County Offaly), the second son of the Danish-born astronomer John Louis Emil Dreyer who was director of the Armagh Observatory. Educated at The Royal School, Armagh, in 1891 Dreyer joined the Royal Navy and entered the Royal Naval College, Dartmouth. Royal Navy career Early years At Dartmouth Dreyer performed well in his examinations and was placed fifth in his term. He then served as a midshipman in HMS ''Anson'' (1893–1896) and HMS ''Barfleur'' (1896–1897). ...
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Elliott Brothers (computer Company)
Elliott Brothers (London) Ltd was an early computer company of the 1950s–60s in the United Kingdom. It traced its descent from a firm of instrument makers founded by William Elliott (1780 or 1781-1853) in London around 1804. The research laboratories were originally set up in 1946 at Borehamwood and the first Elliott 152 computer appeared in 1950. In its day the company was very influential. The computer scientist Bobby Hersom was an employee from 1953-1954, and Sir Tony Hoare was an employee there from August 1960 to 1968. He wrote an ALGOL 60 compiler for the Elliott 803. He also worked on an operating system for the new Elliott 503 Mark II computer. The founder of the UK's first software house, Dina St Johnston, had her first programming job there from 1953–1958, and John Lansdown pioneered the use of computers as an aid to planning on an Elliott 803 computer in 1963. In 1966 the company established an integrated circuit design and manufacturing facility in G ...
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John Saumarez Dumaresq
Rear Admiral John Saumarez Dumaresq ( ;G.M. Miller, ''BBC Pronouncing Dictionary of British Names'' (London: Oxford UP, 1971), p. 48. 26 October 1873 – 22 July 1922) was an officer in the Royal Navy. He served during the First World War but is most remembered as an inventor, for development of the device named after him, the Dumaresq, which helped users calculate the rate at which the range to an enemy ship was changing over time. He was the first Australian born officer to command the Australian Fleet. Early life Dumaresq was the grandson of a British colonial settler, William Dumaresq, who had migrated to Australia, in 1825, accompanying the Governor of New South Wales, Ralph Darling, who was married to his sister, Eliza. He was born at Rose Bay, New South Wales, but left Australia as an infant. In 1907, he married Christian Elizabeth Louisa Dalrymple. Naval career Dumaresq lived in England from age two and became a naval cadet at HMS ''Britannia'' in 1886. He became ...
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Forbes Log
The Forbes Log is an instrument for measuring the speed and distance traveled by ships, notably those of the Royal Navy. They were introduced commercially by Elliott Brothers in 1909 and were fitted to all capital ships by 1912, generally to aid the use of the dumaresq as well as battle reporting. History Elliott Brothers licensed the concept and began production in 1909. It was a standard fit to all capital ships by 1912. The company also licensed the device to Anschütz in 1911, in exchange for a license of Anschütz's gyrocompass technology. The Anschütz compass proved less accurate and less reliable than models introduced in 1913 by Sperry Gyroscope, and the Anschütz models produced by Elliot were replaced with Sperrys. Initial tests of the Forbes Log in 1912 demonstrated it was not entirely accurate, which added to a larger set of problems being encountered by the Navy's new gunlaying instruments. These issues were eventually solved, and the Forbes Log remained a standard ...
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Selsyn
A synchro (also known as selsyn and by other brand names) is, in effect, a transformer whose primary-to-secondary coupling may be varied by physically changing the relative orientation of the two windings. Synchros are often used for measuring the angle of a rotating machine such as an antenna platform. In its general physical construction, it is much like an electric motor. The primary winding of the transformer, fixed to the rotor, is excited by an alternating current, which by electromagnetic induction, causes voltages to appear between the Y-connected secondary windings fixed at 120 degrees to each other on the stator. The voltages are measured and used to determine the angle of the rotor relative to the stator. Uses Synchro systems were first used in the control system of the Panama Canal in the early 1900s to transmit lock gate and valve stem positions, and water levels, to the control desks. Fire-control system designs developed during World War II used synchros ex ...
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