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Océan-class Ironclad
The ''Océan''-class ironclads were a class of three wooden-hulled armored frigates built for the French Navy in the mid to late 1860s. attempted to blockade Prussian ports in the Baltic Sea in 1870 during the Franco-Prussian War and participated in the French conquest of Tunisia in 1881. was often used as the flagship for the Cherbourg Division, the Channel Division, Mediterranean Squadron and the Northern Squadron during her career. The ships were discarded during the 1890s. Design and description The ''Océan''-class ironclads were designed by Henri Dupuy de Lôme as an improved version of the s. The ships were central battery ironclads with the armament concentrated amidships.de Balincourt and Vincent-Bréchignac 1975, p. 26 For the first time in a French ironclad three watertight iron bulkheads were fitted in the hull. Like most ironclads of their era they were equipped with a metal-reinforced ram.Campbell, p. 288 The ships measured overall, with a beam of . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically the first, largest, fastest, most heavily armed, or best known. Over the years, the term "flagship" has become a metaphor used in industries such as broadcasting, automobiles, education, technology, airlines, and retail to refer to their highest profile or most expensive products and locations. Naval use In common naval use, the term ''flagship'' is fundamentally a temporary designation; the flagship is wherever the admiral's flag is being flown. However, admirals have always needed additional facilities, including a meeting room large enough to hold all the captains of the fleet and a place for the admiral's staff to make plans and draw up orders. Historically, only larger ships could accommodate such requirements. The term was also used b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heeling (sailing)
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, windsurfer, or kitesurfer), on ''ice'' (iceboat) or on ''land'' (land yacht) over a chosen course, which is often part of a larger plan of navigation. From prehistory until the second half of the 19th century, sailing craft were the primary means of maritime trade and transportation; exploration across the seas and oceans was reliant on sail for anything other than the shortest distances. Naval power in this period used sail to varying degrees depending on the current technology, culminating in the gun-armed sailing warships of the Age of Sail. Sail was slowly replaced by steam as the method of propulsion for ships over the latter part of the 19th century – seeing a gradual improvement in the technology of steam through a number of stepwise developments. Steam allowed scheduled services that ran at higher average speeds than saili ... [...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. Metacentre When a ship heels (rolls sideways), the centre of buoyancy of the ship moves laterally. It might also move up or down with respect to the water line. The point at which a vertical line through the heeled centre of buoyancy crosses the line through the original, vertical centre of buoyancy is the metacentre. The metacentre remains directly above the centre of buoyancy by definition. In the diagr ... [...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" (or "load lines"). A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (ship)
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 ... [...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, 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 In watercraft, a racing shell (also referred to as just a ''fine boat'' (UK) or just ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Overall
__NOTOC__ 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 A marina (from Spanish , Portuguese and Italian : ''marina'', "coast" or "shore") is a dock or basin with moorings and supplies for yachts and small boats. A marina differs from a port in that a marina does not handle large passenger ships o ... 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 oth ... [...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] |
Bulkhead (partition)
A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads. Etymology The word ''bulki'' meant "cargo" in Old Norse. During the 15th century sailors and builders in Europe realized that walls within a vessel would prevent cargo from shifting during passage. In shipbuilding, any vertical panel was called a head. So walls installed abeam (side-to-side) in a vessel's hull were called "bulkheads". Now, the term bulkhead applies to every vertical panel aboard a ship, except for the hull itself. History Bulkhead partitions are considered to have been a feature of Chinese junks, a type of ship. Song Dynasty author Zhu Yu (fl. 12th century) wrote in his book of 1119 that the hulls of Chinese ships had a bulkhead build. The 5th-century book ''Garden of Strange Things'' by Liu Jingshu mentioned that a ship could allow water to enter the bottom without sinking. Archaeolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Battery Ship
The central battery ship, also known as a centre battery ship in the United Kingdom and as a casemate ship in European continental navies, was a development of the (high- freeboard) broadside ironclad of the 1860s, given a substantial boost due to the inspiration gained from the Battle of Hampton Roads, the first battle between ironclads fought in 1862 during the American Civil War. One of the participants was the Confederate casemate ironclad , essentially a central battery ship herself, albeit a low-freeboard one. The central battery ships had their main guns concentrated in the middle of the ship in an armoured citadel. The concentration of armament amidships meant the ship could be shorter and handier than a broadside type like previous warships. In this manner the design could maximize the thickness of armour in a limited area while still carrying a significant broadside. These ships meant the end of the armoured frigates with their full-length gun decks. In the UK, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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