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HMS Devastation (1871)
HMS ''Devastation'' was the first of two ''Devastation''-class mastless turret ships built for the Royal Navy. This was the first class of ocean-going capital ship that did not carry sails, and the first whose entire main armament was mounted on top of the hull rather than inside it. Design and construction ''Devastation'' was built at a time in which steam power was well-established among the world's larger naval powers. However, most ships built at this time were equipped not only with a steam engine, but also with masts and sails for auxiliary power. The presence of masts also prohibited the use of gun turrets since the rigging would obstruct their arc of fire. ''Devastation'', designed by Sir Edward J. Reed, represented a change from this pattern when she was built without masts and her primary armament, two turrets each with two 12-inch (305 mm) muzzle-loading guns, was placed on the top of the hull, allowing each turret a 280-degree arc of fire. ''Devastation' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portsmouth Dockyard
His Majesty's Naval Base, Portsmouth (HMNB Portsmouth) is one of three operating bases in the United Kingdom for the Royal Navy (the others being HMNB Clyde and HMNB Devonport). 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 (or HM Dockyard, Portsmouth); 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 (from 2002 to 2014), shipbuilding, in the form of block construction, returned. Around 2000, the designation HMS ''Nelson'' (which until then had been specific t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed, by a connecting rod and crank, into rotational force for work. The term "steam engine" is generally applied only to reciprocating engines as just described, not to the steam turbine. Steam engines are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term ''steam engine'' can refer to either complete steam plants (including boilers etc.), such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine. Although steam-driven devices were known as early as the aeoli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenwich
Greenwich ( , ,) is a town in south-east London, England, within the ceremonial county of Greater London. It is situated east-southeast of Charing Cross. Greenwich is notable for its maritime history and for giving its name to the Greenwich Meridian (0° longitude) and Greenwich Mean Time. The town became the site of a royal palace, the Palace of Placentia from the 15th century, and was the birthplace of many Tudors, including Henry VIII and Elizabeth I. The palace fell into disrepair during the English Civil War and was demolished to be replaced by the Royal Naval Hospital for Sailors, designed by Sir Christopher Wren and his assistant Nicholas Hawksmoor. These buildings became the Royal Naval College in 1873, and they remained a military education establishment until 1998 when they passed into the hands of the Greenwich Foundation. The historic rooms within these buildings remain open to the public; other buildings are used by University of Greenwich and Trinity Laban C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller (marine)
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are specially shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the blade to the water at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Bottom
A double hull is a ship hull design and construction method where the bottom and sides of the ship have two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is some distance inboard, typically by a few feet, which forms a redundant barrier to seawater in case the outer hull is damaged and leaks. The space between the two hulls is sometimes used for storage of ballast water. Double hulls are a more extensive safety measure than double bottoms, which have two hull layers only in the bottom of the ship but not the sides. In low-energy collisions, double hulls can prevent flooding beyond the penetrated compartment. In high-energy collisions, however, the distance to the inner hull is not sufficient and the inner compartment is penetrated as well. Double hulls or double bottoms have been required in all passenger ships for decades as part of the Safety Of Life At Sea or SOLAS Convention. Uses Double hulls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Ram
A ram was a weapon fitted to varied types of ships, dating back to antiquity. The weapon comprised an underwater prolongation of the bow of the ship to form an armoured beak, usually between 2 and 4 meters (6–12 ft) in length. This would be driven into the hull of an enemy ship to puncture, sink or disable it. Ancient rams It was possibly developed in late Bronze age Egypt, but it only became widely used in later Iron age Mediterranean galleys. The ram was a naval weapon in the Greek/ Roman antiquity and was used in such naval battles as Salamis and Actium. Naval warfare in the Mediterranean rarely used sails, and the use of rams specifically required oarsmen rather than sails in order to maneuver with accuracy and speed, and particularly to reverse the movement of a ramming ship to disentangle it from its sinking victim, lest it be pulled down when its victim sank. The Athenians were especially known for their '' diekplous'' and '' periplous'' tactics that disabled enemy shi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RML 12 Inch 25 Ton Gun
The RML 12-inch 25-ton guns were large rifled muzzle-loading guns of mid-late 1800s used as primary armament on British ironclad turret battleships and coastal monitors, and also ashore for coast defence. They were the shorter and less powerful of the two 12-inch (305-mm) British RML guns, the other being the 35-ton gun. Design Mark I Four guns were first made in 1866 with a toughened mild steel tube surrounded by multiple wrought iron coils on the original Armstrong pattern. Mark II While strong, the multiple coils were considered too expensive for construction in quantity. From 1867 guns were built on the simplified and hence cheaper "Fraser" system involving fewer but larger coils similar to the 10-inch (254-mm) Mk II gun. The guns were not considered a success, with the rifling twist of 1 in 100 increasing to 1 in 50 considered insufficient for accuracy, and guns were retubed in 11-inch (279-mm) calibre when their bores wore out.Treatise on Construction of Service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freeboard (nautical)
In sailing and boating, a vessel's freeboard is the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship. In commercial vessels, the latter criterion measured relative to the ship's load line, regardless of deck arrangements, is the mandated and regulated meaning. In yachts, a low freeboard is often found on racing boats, for increased speed (by reducing weight and therefore drag). A higher freeboard will give more room in the cabin, but will increase weight and drag, compromising speed. A higher freeboard, such as used on ocean liners, also helps weather waves and so reduce the likelihood of being washed over by full water waves. A low-freeboard vessel is susceptible to taking in water in rough seas. Freighter ships and warships use high freeboard designs to increase internal volume, which also allows them to satisfy International Maritime Organization The International Maritime Organizatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (hull)
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 more heavily a vessel is loaded, the deeper it sinks into the water, and the greater its draft. After construction, the shipyard creates a table showing how much water the vessel displaces based on its draft and the density of the water (salt or fresh). The draft can also be used to determine the weight of cargo on board by calculating the total displacement of water, accounting for the content of the ship's bunkers, and using Archimedes' principle. The closely related term "trim" is defined as the difference between the forward and aft ... [...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 extremities of the ship, beam of the hull (BH) only includes permanently fixed parts of the hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ..., 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 fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muzzle-loading
A muzzleloader is any firearm into which the projectile and the propellant charge is loaded from the muzzle of the gun (i.e., from the forward, open end of the gun's barrel). This is distinct from the modern (higher tech and harder to make) designs of breech-loading firearms. The term "muzzleloader" applies to both rifled and smoothbore type muzzleloaders, and may also refer to the marksman who specializes in the shooting of such firearms. The firing methods, paraphernalia and mechanism further divide both categories as do caliber (from cannons to small-caliber palm guns). Modern muzzleloading firearms range from reproductions of sidelock, flintlock and percussion long guns, to in-line rifles that use modern inventions such as a closed breech, sealed primer and fast rifling to allow for considerable accuracy at long ranges. Modern mortars use a shell with the propelling charge and primer attached at the base. Unlike older muzzleloading mortars, which were loaded the same way as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
