A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Sir Charles Parsons in 1884; because the turbine generates rotary motion, it is suited to be used to drive an electrical generator—about 85% of all electricity generation in the United States in the year 2014 was by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process; the first device that may be classified as a reaction steam turbine was little more than a toy, the classic Aeolipile, described in the 1st century by Hero of Alexandria in Roman Egypt. In 1551, Taqi al-Din in Ottoman Egypt described a steam turbine with the practical application of rotating a spit. Steam turbines were described by the Italian Giovanni Branca and John Wilkins in England.
The devices described by Taqi al-Din and Wilkins are today known as steam jacks. In 1672 an impulse steam turbine driven car was designed by Ferdinand Verbiest. A more modern version of this car was produced some time in the late 18th century by an unknown German mechanic. In 1775 at Soho James Watt designed a reaction turbine, put to work there. In 1827 the Frenchmen Real and Pichon constructed a compound impulse turbine; the modern steam turbine was invented in 1884 by Sir Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kW of electricity. The invention of Parsons' steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. Parsons' design was a reaction type, his patent was the turbine scaled-up shortly after by an American, George Westinghouse. The Parsons turbine turned out to be easy to scale up. Parsons had the satisfaction of seeing his invention adopted for all major world power stations, the size of generators had increased from his first 7.5 kW set up to units of 50,000 kW capacity.
Within Parson's lifetime, the generating capacity of a unit was scaled up by about 10,000 times, the total output from turbo-generators constructed by his firm C. A. Parsons and Company and by their licensees, for land purposes alone, had exceeded thirty million horse-power. A number of other variations of turbines have been developed that work with steam; the de Laval turbine accelerated the steam to full speed before running it against a turbine blade. De Laval's impulse turbine does not need to be pressure-proof, it can operate with any pressure of steam, but is less efficient. Auguste Rateau developed a pressure compounded impulse turbine using the de Laval principle as early as 1896, obtained a US patent in 1903, applied the turbine to a French torpedo boat in 1904, he taught at the École des mines de Saint-Étienne for a decade until 1897, founded a successful company, incorporated into the Alstom firm after his death. One of the founders of the modern theory of steam and gas turbines was Aurel Stodola, a Slovak physicist and engineer and professor at the Swiss Polytechnical Institute in Zurich.
His work Die Dampfturbinen und ihre Aussichten als Wärmekraftmaschinen was published in Berlin in 1903. A further book Dampf und Gas-Turbinen was published in 1922; the Brown-Curtis turbine, an impulse type, developed and patented by the U. S. company International Curtis Marine Turbine Company, was developed in the 1900s in conjunction with John Brown & Company. It was used in John Brown-engined merchant ships and warships, including liners and Royal Navy warships; the present-day manufacturing industry for steam turbines is dominated by Chinese power equipment makers. Harbin Electric, Shanghai Electric, Dongfang Electric, the top three power equipment makers in China, collectively hold a majority stake in the worldwide market share for steam turbines in 2009-10 according to Platts. Other manufacturers with minor market share include Bharat Heavy Electricals Limited, Alstom, General Electric, Doosan Škoda Power, Mitsubishi Heavy Industries, Toshiba; the consulting firm Frost & Sullivan projects that manufacturing of steam turbines will become more consolidated by 2020 as Chinese power manufacturers win increasing business outside of China.
Steam turbines are made in a variety of sizes ranging from small <0.75 kW units used as mechanical drives for pumps and other shaft driven equipment, to 1.5 GW turbines used to generate electricity. There are several classifications for modern steam turbines. Turbine blades are of two basic types and nozzles. Blades move due to the impact of steam on them and their profiles do not converge; this results in a steam velocity drop and no pressure drop as steam moves through the blades. A turbine composed of blades alternating with fixed nozzles is called an impulse turbine, Curtis turbine, Rateau turbine, or Brown-Curtis turbine. Nozzles appear similar to blades; this results in a steam pressure velocity increase as steam moves through the nozzles. Nozzles move due to both the impact of steam on them and the reaction due to the high-velocity steam at the exit. A turbine composed of moving nozzles alternating with fixed nozzles is called a reaction turbine or Parsons turbine. Except for low-power applications, turbine blades are arranged in multiple stages in series, called c
A hangar is a closed building structure to hold aircraft, or spacecraft. Hangars are built of metal and concrete; the word hangar comes from Middle French hanghart, of Germanic origin, from Frankish *haimgard, from *haim and gard. Hangars are used for protection from the weather, direct sunlight, repair, manufacture and storage of aircraft, aircraft carriers and ships; the Wright brothers stored and repaired their aircraft in a wooden hangar constructed in 1902 at Kill Devil Hills in North Carolina for their glider. After completing design and construction of the Wright Flyer in Ohio, the brothers returned to Kill Devil Hill only to find their hangar damaged, they repaired the structure and constructed a new workshop while they waited for the Flyer to be shipped. Carl Richard Nyberg used a hangar to store his 1908 Flugan in the early 20th century and in 1909, Louis Bleriot crash-landed on a northern French farm in Les Baraques and rolled his monoplane into the farmer's cattle pen. Bleriot was in a race to be the first man to cross the English Channel in a heavier-than-air aircraft and set up his headquarters in the unused shed.
In Britain, the earliest aircraft hangars were known as aeroplane sheds and the oldest survivors of these are at Larkhill, Wiltshire. These are now Grade II * Listed buildings. British aviation pioneer Alliott Verdon Roe built one of the first aeroplane sheds in 1907 at Brooklands and full-size replicas of this and the 1908 Roe biplane are on display at Brooklands Museum; as aviation became established in Britain before World War I, standard designs of hangar appeared with military types too such as the Bessonneau hangar and the side-opening aeroplane shed of 1913, both of which were soon adopted by the Royal Flying Corps. Examples of the latter survive at Farnborough and Montrose airfields. During World War I, other standard designs included the RFC General Service Flight Shed and the Admiralty F-Type of 1916, the General Service Shed and the Handley Page aeroplane shed. Airship hangars or airship sheds are larger than conventional aircraft hangars in height. Most early airships used hydrogen gas to provide them with sufficient buoyancy for flight, so their hangars had to provide protection from stray sparks to keep the gas from exploding.
Hangars that held several airships were at risk from chain-reaction explosions. For this reason, most hangars for hydrogen-based airships were built to house only one or two such craft. During the "Golden Age" of airship travel from 1900, mooring masts and sheds were constructed to build and house airships; the British government built a shed in Karachi for the R101, the Brazilian government built one in Rio de Janeiro, the pt:Hangar do Zeppelin for the German Zeppelins and the US government constructed Moffett Field, Akron and Lakehurst Naval Air Station, New Jersey. Sheds built for rigid airships survive at California. Steel rigid airship hangars are some of the largest in the world. Hangar 1, Lakehurst, is located at New Jersey; the structure was completed in 1921 and is typical of airship hangar designs of World War I. The site is best known for the Hindenburg disaster, when on May 6, 1937, the German airship Hindenburg crashed and burned while landing. Hangar No. 1 at Lakehurst was used to store the American USS Shenandoah.
The hangar provided service and storage for the airships USS Los Angeles, Macon, as well as the Graf Zeppelin and the Hindenburg. The largest hangars built include the Goodyear Airdock measuring 1,175x325x211 feet and Hangar One measuring 1,133 ft × 308 ft × 198 ft; the Goodyear Airdock, is in Akron and the structure was completed on November 25, 1929. The Airdock was used for her sister ship, the USS Macon. Hangar One at Moffett Federal Field, is located in California; the structure was completed in 1931. It housed the USS Macon; the US Navy established more airship operations during WWII. As part of this, ten "lighter-than-air" bases across the United States were built as part of the coastal defense plan. Hangars at these bases are some of the world's largest freestanding timber structures. Bases with wooden hangars included: the Naval Air Stations at Massachusetts. Of the seventeen, only seven remain, Moffett Federal Field, California. A hangar for Cargolifter was built at Brand-Briesen Airfield 1,180 ft long, 705 ft wide and 348 ft high and is a free standing steel-dome "barrel-bowl" construction large enough to fit the Eiffel Tower on its side.
The company went into insolvency and in June 2003, the facil
Three-drum boilers are a class of water-tube boiler used to generate steam to power ships. They are compact and of factors that encourage this use. Other boiler designs may be more efficient, although bulkier, so the three-drum pattern was rare as a land-based stationary boiler; the fundamental characteristic of the "three-drum" design is the arrangement of a steam drum above two water drums, in a triangular layout. Water tubes fill in the two sides of this triangle between the drums, the furnace is in the centre; the whole assembly is enclosed in a casing, leading to the exhaust flue. Firing can be by either oil. Many coal-fired boilers used multiple firedoors and teams of stokers from both ends. Development of the three-drum boiler began in the late 19th century, with the demand from naval ships that required high power and a compact boiler; the move to water-tube boilers had begun, with designs such as the Babcock & Wilcox or the Belleville. The three-drum arrangement was more compact for the same power.
The new generation of "small-tube" water-tube boilers used water-tubes of around 2 inches diameter, compared to older designs of 3 or 4 inches. This gave a greater ratio of tube surface heating area to the tube volume, thus more rapid steaming; these small-tube boilers became known as "express" boilers. Although not all of these were three-drum designs, most were some variation of this; as the tubes of the three-drum are close to vertical, this encourages strong circulation by the thermosyphon effect, further encouraging steaming. The development of the three-drum pattern was one of simplification, rather than increasing complexity or sophistication; the first boilers packed a large heating area into a compact volume, their difficulty was in manufacturing and for their maintenance on-board ship. The convoluted tubes of early designs such as the du Temple and Normand were the first to go. A multi-row bank of tubes could provide adequate heating area, without this complexity. Tubes became straighter to ease their cleaning.
Yarrow had demonstrated that straight tubes did not cause any problems with expansion, but circular drums and perpendicular tube entry were both valuable features for a long service life. Where tubes entered drums at an angle and cooling tended to bend the tube back and forth, leading to leaks. A perpendicular entry was easier to expand the tubes for a reliable seal and to avoid these sideways stresses, it was worth the compromise of the Admiralty boiler's bent tube ends to keep these two features, these tubes were still simple enough in shape to clean easily. Some of the first boiler tubes the du Temple with its sharp corners, could not be cleaned of scale internally. Tubes were cleaned internally by attempting to pass a hinged rod through, with a brush at the end. For the curved tube designs only part of the tube could be reached. Another method was to pass a chain down the tube from above, pulling a brush behind it, although this was unworkable for boilers like the Thornycroft where the tubes first travelled horizontally or upwards.
The eventual method was to use'bullet' brushes that were fired from one drum into the other by use of compressed air. Sets of brushes were used, one for each tube, they were numbered and counted afterwards to ensure that none had been left behind, blocking a tube. Separate downcomers were used by most designs after Yarrow's experiments had demonstrated that circulation could still take place amongst the heated tubes alone. Again, the Admiralty boiler was the culmination of this approach, placing the superheater within the tube bank, so as to encourage the necessary temperature difference; the Admiralty boiler is considered to be a direct evolution of the Yarrow, although the White-Forster had an influence as a result of the large number in service with the Royal Navy. The circular water drums, their raising above the furnace floor, are White-Forster features; the first reduces the risk of grooving, the latter is appropriate for oil firing. The du Temple was an early naval water-tube boiler, patented in 1876.
It was tested in a Royal Navy torpedo gunboat. Water tubes were convoluted, arranged in four rows to a bank, S-shaped with sharp right angle bends; this made tube cleaning impractical. The drums were cylindrical, with external downcomers between them; the White-Forster was with tubes that had only a gentle curvature to them. This was sufficient to allow them to be replaced in-situ, working through the manhole at the end of the large steam drum; each tube was sufficiently curved to allow it to be extracted through the steam drum, but sufficiently straight that a single tube could be replaced from a tube bank, without requiring other tubes to be removed so as to permit access. This was one of many features of the White-Forster intended to make it reliable in naval service and easy to maintain; these tubes were of small diameter, only 1 inch and numerous, a total of 3,744 being used in some boilers. The tubes were arranged in 24 rows to a bank, each requiring a different length of tube, 78 rows per drum.
All tubes were curved to the same radius, facilitating repair and replacement on board, but requiring the tube holes in the drums to be reamed to precise angles on a jig during manufacture. This small tube diameter gave a high heating surface, but too much: the ratio of surface to volume became excessive and gas flow through the
QF 4-inch naval gun Mk XVI
The QF 4 inch Mk XVI gun was the standard British Commonwealth naval anti-aircraft and dual-purpose gun of World War II. The Mk XVI superseded the earlier QF 4 inch Mk V naval gun on many Royal Naval ships during the late 1930s and early 1940s; the ammunition fired by the Mk V gun and the Mk XVI guns was different. The Mk V ammunition was 44.3 inches long and weighed 56 pounds, while the ammunition fired by the Mk XVI gun was 42.1 inches long and weighed 66.75 pounds. The weight of the high-explosive projectile grew from 31 pounds for the Mk V to 35 pounds for the Mk XVI. There were three variants of the gun produced with differing construction methods; the original Mk XVI had an A tube, jacket to 63.5 inches from the muzzle and a removable breech ring. The Mk XVI* replaced the A tube with an autofretted loose barrel with a sealing collar at the front of the jacket; the Mk XXI was a lighter version with a removable breech ring. The total number of Mk XVI and XVI* guns produced was 2,555 while there were 238 Mk XXI guns produced.
Of those totals 604 Mk XVI* and 135 of the Mk XXI guns were produced in Canada and 45 of the Mk XVI* were produced in Australia. These guns were mounted on HA/LA Mark XIX twin mountings, although several Australian frigates and corvettes had single-gun Mk XX mountings; the last Royal Navy ship to operate with a Mark XIX twin mounting was HMS Mermaid, designed for the Ghana Navy and so required a simple and inexpensive main armament. Acquired by the British Government in 1972, she served until 1977 when she was purchased by the Royal Malaysian Navy and renamed KD Hang Tuah. HMS Hood HMS Rodney HMS Barham, HMS Malaya, HMS Warspite Revenge-class battleships HNLMS Jacob van Heemskerck County-class cruisers HMS Exeter Swiftsure-class cruisers Crown Colony-class cruisers Edinburgh-class cruisers Southampton-class cruisers Arethusa-class cruisers Perth-class cruisers Leander-class cruisers HMS Effingham HMS Danae Aircraft carriers: HMS Furious, HMS Unicorn Escort carriers: Nairana-class escort carriers, HMS Pretoria Castle, HMS Activity C-class cruisers Abdiel-class minelayers Tribal-class destroyers L and M-class destroyer HMS Petard Weapon-class destroyers V and W-class destroyers HMS Wallace Hunt-class destroyers Some Bathurst-class corvettes Black Swan-class sloops Egret-class sloops Bittern-class sloop Grimsby-class sloop Bay-class frigates River-class frigates 8 auxiliary AA defence ships Some landing ships ORP Błyskawica HNLMS Jacob van Heemskerck HNLMS Isaac Sweers 4 French Elan-class avisos and Chamois-class avisosThe South African Navy Loch-class frigates each had two of these guns mounted on a twin Mark XIX on their foredeck between 1944 and 1976.
QF 4 inch Mk V naval gun: Royal Navy anti-aircraft predecessor List of naval anti-aircraft guns List of naval guns On HMCS Haida, Ortario, Canada. Naval Museum of Alberta, Canada On HMS Belfast, which retains four twin guns. Explosion! Museum of Naval Firepower, Hampshire, UK On ORP Błyskawica, Gdynia. A pair at South African National Museum of Military History, Johannesburg A pair in a turret from INS Haifa, at Clandestine Immigration and Naval Museum, Israel. Two single guns on HMAS Diamantina, Australia One twin gun at the Marinemuseet, Norway. One twin gun in the Aldhurst military vehicles collection, Surrey England. Further research has proven the left gun was installed on the heavy cruiser HMS Devonshire from 1943 till she was scrapped in 1954. Campbell, John. Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4. B. R. 257. Handbook for the 4 inch Q. F. Mark XVI* Gun on the H. A. Twin Mark XIX And Single Mark XX Mountings. G3821/41 Naval Ordnance Department, July 1941. Tony DiGiulian, British 4"/45 QF HA Marks XVI, XVII, XVIII and XXI Youtube video clip of demonstration of loading and firing on HMS Belfast Youtube video clip of demonstration of loading and firing on HMS Belfast: closeup Note: for safety reasons, cartridges are seen being loaded without the normal attached shell
British Pacific Fleet
The British Pacific Fleet was a Royal Navy formation which saw action against Japan during the Second World War. The fleet was composed of British Commonwealth naval vessels; the BPF formally came into being on 22 November 1944 from the remaining ships of the former Eastern Fleet being re-designated the East Indies Fleet and continuing to be based in Trincomalee. The British Pacific Fleet's main base was at Sydney, with a forward base at Manus Island. One of the largest fleets assembled by the Royal Navy, by VJ Day it had four battleships and six fleet aircraft carriers, fifteen smaller aircraft carriers, eleven cruisers, numerous smaller warships and support vessels. Following their retreat to the western side of the Indian Ocean in 1942, British naval forces did not return to the South West Pacific theatre until 17 May 1944, when an Anglo-American carrier task force implemented Operation Transom, a joint raid on Surabaya, Java; the US was extending its influence. It was therefore seen as a political and military imperative by the British Government to restore a British presence in the region and to deploy British forces against Japan.
The British Government was determined that British territories, such as Hong Kong, should be recaptured by British forces. The British Government was not unanimous on the commitment of the BPF. Churchill, in particular, argued against it, not wishing to be a visibly junior partner in what had been the United States' battle, he considered that a British presence would be unwelcome and should be concentrated on Burma and Malaya. Naval planners, supported by the Chiefs of Staff, believed that such a commitment would strengthen British influence and the British Chiefs of Staff considered mass resignation, so held were their opinions; the Admiralty had proposed a British role in the Pacific in early 1944 but the initial USN response had been discouraging. Admiral Ernest King, Commander-in-Chief United States Fleet and Chief of Naval Operations, an Anglophobe, was reluctant to concede any such role and raised a number of objections, insisted that the BPF should be self-sufficient; these were overcome or discounted and at a meeting, US President Franklin D. Roosevelt "intervened to say that the British Fleet was no sooner offered than accepted.
In this, though the fact was not mentioned, he overruled Admiral King's opinion."The Australian Government had sought US military assistance in 1942, when it was faced with the possibility of Japanese invasion. While Australia had made a significant contribution to the Pacific War, it had never been an equal partner with its US counterparts in strategy, it was argued that a British presence would act as a counterbalance to the powerful and increasing US presence in the Pacific. The fleet was founded when Admiral Sir Bruce Fraser struck his flag at Trincomalee as Commander-in-Chief of the British Eastern Fleet and hoisted it in the gunboat Tarantula as Commander-in-Chief British Pacific Fleet, he transferred his flag to a more suitable vessel, the battleship Howe. The Eastern Fleet was based in Ceylon, reorganised into the British East Indies Fleet, subsequently becoming the British Pacific Fleet; the BPF operated against targets in Sumatra, gaining experience until early 1945, when it departed Trincomalee for Sydney.
The Royal Navy provided the majority of the fleet's vessels and all the capital ships but elements and personnel included contributions from the Royal Fleet Auxiliary, as well as the Commonwealth nations, including the Royal Australian Navy, Royal Canadian Navy and Royal New Zealand Navy. With its larger vessels integrated with United States Navy formations since 1942, the RAN's contribution was limited. A high proportion of naval aviators were Canadians; the USN contributed to the BPF, as did personnel from the South African Navy. Port facilities in Australia and New Zealand made vital contributions in support of the British Pacific Fleet. During World War II, the fleet was commanded by Admiral Sir Bruce Fraser. In practice, command of the fleet in action devolved to Vice-Admiral Sir Bernard Rawlings, with Vice-Admiral Sir Philip Vian in charge of air operations by the Royal Navy's Fleet Air Arm; the fighting end of the fleet was referred to as Task Force 37 or 57 and the Fleet Train was Task Force 113.
The 1st Aircraft Carrier Squadron was the lead carrier formation. No. 300 Wing RAF was established in Australia in late 1944 to fly transport aircraft in support of the BPF, came under the direct command of Fraser. The wing was expanded to a group in 1945 and conducted regular flights from Sydney to the fleet's forward bases; the requirement that the BPF be self-sufficient meant the establishment of a fleet train that could support a naval force at sea for weeks or months. The Royal Navy had been accustomed to operating close to its bases in Britain, the Mediterranean and the Indian Ocean. Infrastructure and expertise were lacking in the Pacific rim. In the north Atlantic and Mediterranean, the high risk of submarine and air attack precluded routine refuelling at sea. For the BPF "the American logistics authorities... interpreted self-sufficiency in a liberal sense." American officers told Rear Admiral Douglas Fisher, commander of the British Fleet Train, that he could have anything and everything "that could be given without Admiral King's knowledge."The Admiralty sent Vice Admiral Charles Daniel to the United States for consultation about the supply and administration of the fleet.
He proceeded to Australia where he became Vice Admiral, British Pacifi
The displacement or displacement tonnage of a ship is its weight based on the amount of water its hull displaces at varying loads. It is measured indirectly using Archimedes' principle by first calculating the volume of water displaced by the ship converting that value into weight displaced. Traditionally, various measurement rules have been in use. Today, metric tonnes are more used. Ship displacement varies by a vessel's degree of load, from its empty weight as designed to its maximum load. Numerous specific terms are detailed below. Ship displacement should not be confused with measurements of volume or capacity used for commercial vessels, such as net tonnage, gross tonnage, or deadweight tonnage; the process of determining a vessel's displacement begins with measuring its draft This is accomplished by means of its "draft marks". A merchant vessel has three matching sets: one mark each on the port and starboard sides forward and astern; these marks allow a ship's displacement to be determined to an accuracy of 0.5%.
The draft observed at each set of marks is averaged to find a mean draft. The ship's hydrostatic tables show the corresponding volume displaced. To calculate the weight of the displaced water, it is necessary to know its density. Seawater is more dense than fresh water; the density of water varies with temperature. Devices akin to slide rules have been available, it is done today with computers. Displacement is measured in units of tonnes or long tons. There are terms for the displacement of a vessel under specified conditions: Loaded displacement is the weight of the ship including cargo, fuel, stores and such other items necessary for use on a voyage; these bring the ship down to its "load draft", colloquially known as the "waterline". Full load displacement and loaded displacement have identical definitions. Full load is defined as the displacement of a vessel when floating at its greatest allowable draft as established by a classification society. Warships have arbitrary full load condition established.
Deep load condition means stores, with most available fuel capacity used. Light displacement is defined as the weight of the ship excluding cargo, water, stores, crew, but with water in boilers to steaming level. Normal displacement is the ship's displacement "with all outfit, two-thirds supply of stores, etc. on board." Standard displacement known as "Washington displacement", is a specific term defined by the Washington Naval Treaty of 1922. It is the displacement of the ship complete manned and equipped ready for sea, including all armament and ammunition, outfit and fresh water for crew, miscellaneous stores, implements of every description that are intended to be carried in war, but without fuel or reserve boiler feed water on board. Naval architecture Hull Hydrodynamics Tonnage Dear, I. C. B.. Oxford Companion to Ships and the Sea. Oxford: Oxford University Press. ISBN 0-19-920568-X. George, William E.. Stability & Trim for the Ship's Officer. Centreville, Md: Cornell Maritime Press. ISBN 0-87033-564-2.
Hayler, William B.. American Merchant Seaman's Manual. Cambridge, Md: Cornell Maritime Press. ISBN 0-87033-549-9.. Turpin, Edward A.. Merchant Marine Officers' Handbook. Centreville, MD: Cornell Maritime Press. ISBN 0-87033-056-X. Navy Department. "Nomenclature of Naval Vessels". History.navy.mil. United States Navy. Retrieved 2008-03-24. Military Sealift Command. "Definitions and Equivalents". MSC Ship Inventory. United States Navy. Retrieved 2008-03-24. MLCPAC Naval Engineering Division. "Trim and Stability Information for Drydocking Calculations". United States Coast Guard. Retrieved 2008-03-24. United States of America. "Conference on the Limitation of Armament, 1922". Papers Relating to the Foreign Relations of the United States: 1922. 1. Pp. 247–266. United States Naval Institute. Proceedings of the United States Naval Institute. United States Naval Institute. Retrieved 2008-03-24
The Royal Navy is the United Kingdom's naval warfare force. Although warships were used by the English kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years War against the Kingdom of France; the modern Royal Navy traces its origins to the early 16th century. From the middle decades of the 17th century, through the 18th century, the Royal Navy vied with the Dutch Navy and with the French Navy for maritime supremacy. From the mid 18th century, it was the world's most powerful navy until surpassed by the United States Navy during the Second World War; the Royal Navy played a key part in establishing the British Empire as the unmatched world power during the 19th and first part of the 20th centuries. Due to this historical prominence, it is common among non-Britons, to refer to it as "the Royal Navy" without qualification. Following World War I, the Royal Navy was reduced in size, although at the onset of World War II it was still the world's largest.
By the end of the war, the United States Navy had emerged as the world's largest. During the Cold War, the Royal Navy transformed into a anti-submarine force, hunting for Soviet submarines and active in the GIUK gap. Following the collapse of the Soviet Union, its focus has returned to expeditionary operations around the world and remains one of the world's foremost blue-water navies. However, 21st century reductions in naval spending have led to a personnel shortage and a reduction in the number of warships; the Royal Navy maintains a fleet of technologically sophisticated ships and submarines including two aircraft carriers, two amphibious transport docks, four ballistic missile submarines, six nuclear fleet submarines, six guided missile destroyers, 13 frigates, 13 mine-countermeasure vessels and 22 patrol vessels. As of November 2018, there are 74 commissioned ships in the Royal Navy, plus 12 ships of the Royal Fleet Auxiliary; the RFA replenishes Royal Navy warships at sea, augments the Royal Navy's amphibious warfare capabilities through its three Bay-class landing ship vessels.
It works as a force multiplier for the Royal Navy doing patrols that frigates used to do. The total displacement of the Royal Navy is 408,750 tonnes; the Royal Navy is part of Her Majesty's Naval Service, which includes the Royal Marines. The professional head of the Naval Service is the First Sea Lord, an admiral and member of the Defence Council of the United Kingdom; the Defence Council delegates management of the Naval Service to the Admiralty Board, chaired by the Secretary of State for Defence. The Royal Navy operates three bases in the United Kingdom; as the seaborne branch of HM Armed Forces, the RN has various roles. As it stands today, the RN has stated its 6 major roles as detailed below in umbrella terms. Preventing Conflict – On a global and regional level Providing Security At Sea – To ensure the stability of international trade at sea International Partnerships – To help cement the relationship with the United Kingdom's allies Maintaining a Readiness To Fight – To protect the United Kingdom's interests across the globe Protecting the Economy – To safe guard vital trade routes to guarantee the United Kingdom's and its allies' economic prosperity at sea Providing Humanitarian Aid – To deliver a fast and effective response to global catastrophes The strength of the fleet of the Kingdom of England was an important element in the kingdom's power in the 10th century.
At one point Aethelred II had an large fleet built by a national levy of one ship for every 310 hides of land, but it is uncertain whether this was a standard or exceptional model for raising fleets. During the period of Danish rule in the 11th century, the authorities maintained a standing fleet by taxation, this continued for a time under the restored English regime of Edward the Confessor, who commanded fleets in person. English naval power declined as a result of the Norman conquest. Following the Battle of Hastings, the Norman navy that brought over William the Conqueror disappeared from records due to William receiving all of those ships from feudal obligations or because of some sort of leasing agreement which lasted only for the duration of the enterprise. More troubling, is the fact that there is no evidence that William adopted or kept the Anglo-Saxon ship mustering system, known as the scipfryd. Hardly noted after 1066, it appears that the Normans let the scipfryd languish so that by 1086, when the Doomsday Book was completed, it had ceased to exist.
According to the Anglo-Saxon Chronicle, in 1068, Harold Godwinson's sons Godwine and Edmund conducted a ‘raiding-ship army’ which came from Ireland, raiding across the region and to the townships of Bristol and Somerset. In the following year of 1069, they returned with a bigger fleet which they sailed up the River Taw before being beaten back by a local earl near Devon. However, this made explicitly clear that the newly conquered England under Norman rule, in effect, ceded the Irish Sea to the Irish, the Vikings of Dublin, other Norwegians. Besides ceding away the Irish Sea, the Normans ceded the North Sea, a major area where Nordic peoples traveled. In 1069, this lack of naval presence in the North Sea allowed for the invasion an