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B-class Destroyer
The A- and B-class destroyers were a group of 18 destroyers built for the Royal Navy during the late 1920s, with two additional ships built for the Royal Canadian Navy. The British ships were divided into two flotillas of eight destroyers, each with a flotilla leader. Design and description The A-class design was derived from the 1926 prototypes and for the 1927–28 Naval Construction Programme. The initial staff requirements were unrealistic and would have resulted in a much larger, unaffordable ship; they were scaled back, both to reduce the size of the ship and to save money. Nonetheless, the design had an improved gun armament, heavier torpedo armament, and greater range, at the cost of of speed, in comparison with the prototypes. The As were fitted with the Two-Speed Destroyer Sweep (TSDS) minesweeping gear and only had a residual anti-submarine ability while the Bs were equipped with Type 119 ASDIC (sonar) and had a full complement of depth charges, but could not us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HMS Basilisk (H11)
HMS ''Basilisk'' was a built for the Royal Navy around 1930. Initially assigned to the Mediterranean Fleet, she was transferred to the Home Fleet in 1936. The ship escorted convoys and conducted anti-submarine patrols early in World War II before participating in the Norwegian Campaign. ''Basilisk'' was sunk by German aircraft during the Dunkirk evacuation in 1940. Description ''Basilisk'' displaced at standard load and at deep load. The ship had an overall length of , a beam of and a draught of . She was powered by a pair of Brown-Curtis geared steam turbines, each driving one shaft, using steam provided by three Admiralty 3-drum boilers. The turbines developed a total of and gave a maximum speed of . ''Basilisk'' carried enough fuel oil to give her a range of at .Whitley, p. 99 The ship's complement was 134 officers and ratings, although it increased to 142 during wartime.Friedman, p. 298 The B-class destroyers mounted four QF 4.7-inch (120 mm) Mk IX ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minesweeper
A minesweeper is a small warship designed to remove or detonate naval mines. Using various mechanisms intended to counter the threat posed by naval mines, minesweepers keep waterways clear for safe shipping. History The earliest known usage of the naval mine dates to the Ming dynasty.Needham, Volume 5, Part 7, 203–205. Dedicated minesweepers, however, only appeared many centuries later during the Crimean War, when they were deployed by the British. The Crimean War minesweepers were rowboats trailing Grappling hook, grapnels to snag mines. Minesweeping technology picked up in the Russo-Japanese War, using aging torpedo boats as minesweepers. In Britain, naval leaders recognized before the outbreak of World War I that the development of sea mines was a threat to the nation's shipping and began efforts to counter the threat. Sir Arthur Wilson, 3rd Baronet, Sir Arthur Wilson noted the real threat of the time was a blockade aided by mines and not an invasion. The function of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water-tube Boiler
A high pressure watertube boiler (also spelled water-tube and water tube) is a type of boiler in which water circulates in tubes heated externally by fire. Fuel is burned inside the furnace, creating hot gas which boils water in the steam-generating tubes. In smaller boilers, additional generating tubes are separate in the furnace, while larger utility boilers rely on the water-filled tubes that make up the walls of the furnace to generate steam. The heated water/steam mixture then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. In some services, the steam passes through tubes in the hot gas path, (a superheater) to become superheated. Superheated steam is a dry gas and therefore is typically used to drive turbines, since water droplets can severely damage turbine blades. Saturated water at the bottom of the steam drum returns to the lower drum via large-bore 'downcomer tubes', where it pre-heats the feedwater supply. (In large utility boilers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller Shaft
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power, torque, and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint. History The term ''driveshaft'' first appeared during the mid-19th cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parsons Marine Steam Turbine Company
Parsons Marine Steam Turbine Company was a United Kingdom of Great Britain and Ireland, British engineering company based on the River Tyne at Wallsend, North East England. History Charles Algernon Parsons founded the company in 1897 with £500,000 of capital. It specialised in building the steam turbine engines that he had invented for marine use. The first vessel powered by a Parsons turbine was ''Turbinia'', launched in 1894. The successful demonstration of this vessel led to the creation of the company and the building of engines for the first two turbine-powered destroyers for the Royal Navy, and , launched in 1899. Although both these vessels came to grief, the new engines were not to blame, and the British Admiralty, Admiralty was convinced. Parsons' son became a director in the company and was replaced during the First World War by his daughter Rachel Mary Parsons, Rachel Parsons. Parsons turbines powered the Royal Navy's first turbine powered battleship, , and the wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Rating
In military terminology, a rate or rating (also known as bluejacket in the United States) is a junior enlisted sailor in a navy who is below the military rank of warrant officer. Depending on the country and navy that uses it, the exact term and the range of ranks that it refers to may vary. Royal Navy In the Royal Navy (RN) and other navies in the Commonwealth, ''rate'' and ''rating'' are interchangeably used to refer to an enlisted sailor who is ranked below warrant officers and commissioned officers, but may include petty officers and chief petty officers. Specifically, ''rate'' is the term used to describe generically all members of all ranks below a warrant officer; whereas ''rating'' is part of the official name of individual specific ranks, such as Able Rating and Leading Rating. The term comes from the general nautical usage of 'rating', to refer to a seaman's class or grade as recorded in the ship's books. The system of conferring authority on sailors i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacentric Height
The metacentric height (GM) is a measurement of the initial static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its '' metacentre''. A larger metacentric height implies greater initial stability against overturning. The metacentric height also influences the natural period of rolling of a hull, with very large metacentric heights being associated with shorter periods of roll which are uncomfortable for passengers. Hence, a sufficiently, but not excessively, high metacentric height is considered ideal for passenger ships. Different centres The ''centre of buoyancy'' is at the centre of mass of the volume of water that the hull displaces. This point is referred to as B in naval architecture. The '' centre of gravity'' of the ship is commonly denoted as point G or CG. When a ship is at equilibrium, the centre of buoyancy is vertically in line with the centre of gravity of the ship. The metacentre is the point where th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (hull)
The draft or draught of a ship is a determined depth of the vessel below the waterline, measured vertically to its hull's lowest—its propellers, or keel, or other reference point. Draft varies according to the loaded condition of the ship. A deeper draft means the ship will have greater vertical depth below the waterline. Draft is used in under keel clearance calculations, where the draft is calculated with the available depth of water (from Electronic navigational charts) to ensure the ship can navigate safely, without grounding. Navigators can determine their draught by calculation or by visual observation (of the ship's painted load lines). Related terminology A ship's draft/draught is the "depth of the vessel below the waterline measured vertically to the lowest part of the hull, propellers, or other reference point". That is, the draft or draught is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam (nautical)
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 sides 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. Generally speaking, the wider the beam of a ship (or boat), the more initial stability it has, at the expense of secondary stability in the event of a capsize, where more energy is required to right the vessel from its inverted position. A ship that heels on her ''beam ends'' has her deck beams nearly vertical. Typical values Typical length-to-beam ratios ( aspect ratios) for small sailboats are from 2:1 (dinghies to trailerable sailboats around ) to 5:1 (racing sailboats over ). Large ships have widely varying beam ratios, some as large as 20:1. Rowing shells designed for flatwater racing may have length to beam ratios as high as 30:1, while a cora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Overall
Length overall (LOA, o/a, o.a. or oa) 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 (for example, £2.50 per metre LOA). LOA is usually measured on the hull alone. For sailing ships, this may ''exclude'' the bowsprit and other fittings added to the hull. This is how some racing boats and tall ships use the term LOA. However, other sources may include bowsprits in LOA. Confusingly, LOA has different meanings. "Sparred length", "Total length including bowsprit", "Mooring length" and "LOA including bowsprit" are other expressions that might indicate the full length of a sailing ship. LOD Often used to distinguish between the length of a vessel including projections (e.g. bow sprits, etc.) from the length of the hull itself, the Length on Deck or LOD is often reported. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Displacement (ship)
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. Ship displacement varies by a vessel's degree of load, from its empty weight as designed (known as "lightweight tonnage") to its maximum load. Numerous specific terms are used to describe varying levels of load and trim, detailed below. Ship displacement should not be confused with measurements of volume or capacity typically used for commercial vessels and measured by tonnage: net tonnage and gross tonnage. Calculation The process of determining a vessel's displacement begins with measuring its draft.George, 2005. p. 5. This is accomplished by means of its "draft marks". A merchant vessel has t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Admiralty
The Admiralty was a Departments of the Government of the United Kingdom, department of the Government of the United Kingdom that was responsible for the command of the Royal Navy. Historically, its titular head was the Lord High Admiral of the United Kingdom, Lord High Admiral – one of the Great Officers of State. For much of its history, from the early Admiralty in the 18th century, 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 (United Kingdom), Admiralty Board in 1964, as part of the reforms that created the Ministry of Defence (United Kingdom), Ministry of Defence and its Navy Department (Ministry of Defence), Navy Department (later Navy Command (Ministry of Defence), Navy Command). Before the Acts of Union 1707, the Office of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
