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Leeboard
A leeboard is a form of pivoting keel used by a sailboat largely and very often in lieu of a fixed keel. Typically mounted in pairs on each side of a hull, leeboards function much like a centreboard, allowing shallow-draft craft to ply waters fixed keel boats cannot. Only the leeward side leeboard is used at any time, as it submerges when the boat heels under the force of the wind. A disadvantage, where there is an inadequate fixed keel, is that they typically ship (bear) little ballast, which being on the far side delays the onset of unballasted craft's heeling, that is, to put up a good, constant resistance against the wind. The classical, archetypal definition of ballast is a low, central weight to optimise centre of mass, reduce turning moment and therefore resistance to the boat keeling over, however tends to be higher in self-righting vessels. Modern developments allow them to act as a speed-enhancing lifting foil. History Leeboards existed in China from at least the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Inventions
China has been the source of many innovations, scientific discoveries and inventions. This includes the ''Four Great Inventions'': papermaking, the compass, gunpowder, and printing (both woodblock and movable type). The list below contains these and other inventions in ancient and modern China attested by archaeological or historical evidence, excluding prehistoric inventions of Neolithic and early Bronze Age China. The historical region now known as China experienced a history involving mechanics, hydraulics and mathematics applied to horology, metallurgy, astronomy, agriculture, engineering, music theory, craftsmanship, naval architecture and warfare. Use of the plow during the Neolithic period Longshan culture (c. 3000–c. 2000 BC) allowed for high agricultural production yields and rise of Chinese civilization during the Shang Dynasty (c. 1600–c. 1050 BC). Later inventions such as the multiple-tube seed drill and the heavy moldboard iron plow enabled Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keel
The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in British and American shipbuilding traditions the construction is dated from this event. Etymology The word "keel" comes from Old English , Old Norse , = "ship" or "keel". It has the distinction of being regarded by some scholars as the first word in the English language recorded in writing, having been recorded by Gildas in his 6th century Latin work '' De Excidio et Conquestu Britanniae'', under the spelling ''cyulae'' (he was referring to the three ships that the Saxons first arrived in). is the Latin word for "keel" and is the origin of the term careen (to clean a keel and the hull in general, often by rolling the ship on its side). An example of this use is Careening Cove, a suburb of Sydney, Australia, where careening was carried o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centreboard
A centreboard or centerboard (US) is a retractable hull appendage which pivots out of a slot in the hull of a sailboat, known as a ''centreboard trunk'' (UK) or ''centerboard case'' (US). The retractability allows the centreboard to be raised to operate in shallow waters, to move the centre of lateral resistance (offsetting changes to the sailplan that move the centre of effort aft), to reduce drag when the full area of the centreboard is not needed, or when removing the boat from the water, as when trailering. A centreboard which consists of solely a pivoting metal plate is called a centerplate. A daggerboard is similar but slides vertically rather than pivoting. The analog in a scow is a bilgeboard: these are fitted in pairs and used one at a time. General History Lt. John Schank (c. 1740 – 6 February 1823) was an officer of the British Royal Navy and is credited with the invention of the centerboard. Schank, however, gave credit for the idea to British Brigadier Gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Junk (boat)
A junk (Chinese: 船, ''chuán'') is a type of Chinese sailing ship with fully battened sails. There are two types of junk in China: northern junk, which developed from Chinese river boats, and southern junk, which developed from Austronesian ships visiting southern Chinese coasts since the 3rd century CE. They continued to evolve in later dynasties and were predominantly used by Chinese traders throughout Southeast Asia. Similar junk sails were also adopted by other East Asian countries, most notably Japan where junks were used as merchant ships to trade goods with China and Southeast Asia. They were found, and in lesser numbers are still found, throughout Southeast Asia and India, but primarily in China. Historically, a Chinese junk could be one of many types of small coastal or river ships, usually serving as a cargo ship, pleasure boat, or houseboat, but also ranging in size up to large ocean-going vessel. Found more broadly today is a growing number of modern recreational ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames Sailing Barge
A Thames sailing barge is a type of commercial sailing boat once common on the River Thames in London. The flat-bottomed barges with a shallow draught and leeboards, were perfectly adapted to the Thames Estuary, with its shallow waters and narrow tributary rivers. The larger barges were seaworthy vessels, and were the largest sailing vessel to be handled by just two men. The average size was about 120 tons and they carried of canvas sail in six working sails. The mainsail was loose-footed and set up with a sprit, and was brailed to the mast when not needed. It is sheeted to a horse, as is the foresail; they require no attention when tacking. The foresail is often held back by the mate to help the vessel come about more swiftly. The topsail was usually first sail on and last sail off, being fixed to the topmast by hoops. In the upper reaches of the rivers and constricted harbours it reached into the clear air, and when approaching a berth casting off the halliard would drop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klipper Pegasus Kieler Woche 2008
Klipper is a clipboard manager for the KDE interface. It allows users of Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ... operating systems running the KDE desktop environment to access a history of X Selections, any item of which can be reselected for pasting. It can also be used to perform an action automatically if certain text is selected (e.g. opening a URL in a browser). References External linksThe Klipper Handbook Clipboard (computing) KDE software KDE Software Compilation {{KDE-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cabin (ship)
A cabin or berthing is an enclosed space generally on a ship or an aircraft. A cabin which protrudes above the level of a ship's deck may be referred to as a deckhouse. Sailing ships In sailing ships, the officers and paying passengers would have an individual or shared cabin. The captain or commanding officer would occupy the "great cabin" that normally spanned the width of the stern and had large windows. On a warship, it was a privileged area, separate from the rest of the ship, for the exclusive use of the captain. In large warships, the cabin was subdivided into day and night cabins (bedrooms) by movable panels, called '' bulk-heads'', that could be removed in time of battle to leave the cabin clear for the gunners to use the stern chasers several of which were usually stationed in the cabin. On large three decker warships in the age of sail the captain's cabin was sometimes appropriated by the Admiral. The captain would be consigned to the cabin below on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruce Foil
A Bruce foil is a variant of the leeboard, consisting of a hydrofoil, foil typically mounted on an outrigger and always set at an angle to provide both lateral and vertical force. It was invented by Edmond Bruce in the early 1960s, and first published in the Amateur Yacht Research Society publication in April 1965. Theory Nearly all methods that increase resistance to sideways movement also cause Heeling (sailing), heeling, the leaning produced by the imbalance of the forces on the sails, high above the waterline, and the sideways resistance, generated by the centerboard or other foil (fluid mechanics), foil below the waterline. The resulting torque causes the hull to heel until the buoyancy of the hull provides sufficient torque to balance the heeling force. The limited buoyancy of the hull therefore limits the amount of force that the sail can effectively produce. One solution to dealing with this limit is to bring the forces generated by the sail and the underwater foil into ali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bilgeboard
A bilgeboard is a lifting foil used in a sailboat, which resembles a cross between a centerboard and a leeboard. Bilgeboards are mounted between the centerline of the boat and the sides, and are almost always asymmetric foils mounted at an angle to maximize lateral lift while minimizing drag. They are most often found on racing scows. When sailing, the windward side bilgeboard is retracted into the hull of the boat, so that it produces no drag. The leeward side foil provides the lift to counter the lateral force of the sail, and converts it into forward motion. The bilgeboards are angled so that as the boat heels, or leans under the force of the wind, the leeward bilgeboard becomes more upright, and provides the greatest possible force in the desired direction. Like a centerboard, the bilgeboard can be used as a recovery platform upon which to stand in the event the dinghy overturns via a capsize or turtle. The ''Red Fox'' is a modern cruising yacht that uses bilgeboards to al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scow
A scow is a smaller type of barge. Some scows are rigged as sailing scows. In the 19th and early 20th centuries, scows carried cargo in coastal waters and inland waterways, having an advantage for navigating shallow water or small harbours. Scows were in common use in the American Great Lakes and other parts of the U.S., Canada, southern England, and New Zealand. In modern times their main purpose is for recreation and racing. Scows The name "scow" derives from the Dutch , ultimately from the German for a punt pole and subsequently transferred to mean the boat. Old Saxon has a similar word which means to push from the shore, clearly related to punting. The basic scow was developed as a flat-bottomed barge ( a large punt) capable of navigating shallow rivers and sitting comfortably on the bottom when the tide was out. By 1848 scows were being rigged for sailing using leeboards or sliding keels. They were also used as dumb barges towed by steamers. Dumb scows were used for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windward
Windward () and leeward () are terms used to describe the direction of the wind. Windward is ''upwind'' from the point of reference, i.e. towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference, i.e. along the direction towards which the wind is going. The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind, the lee side will be the "lower side". During the Age of Sail, the term ''weather'' was used as a synonym for ''windward'' in some contexts, as in the ''weather gage''. Because it captures rain, the windward side of a mountain tends to be wet compared to the leeward it blocks. Origin The term "lee" comes from the middle-low German word // meaning "where the sea is not exposed to the wind" or "mild". The terms Luv and Lee (engl. Windward and Leeward) have been in use since the 17th century. Usage Windward and leeward directions (and the points of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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