Shear Legs
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Shear Legs
Shear legs, also known as sheers, shears, or sheer legs, are a form of two-legged lifting device. Shear legs may be permanent, formed of a solid A-frame and supports, as commonly seen on land and the floating sheerleg, or temporary, as aboard a vessel lacking a fixed crane or derrick. When fixed, they are often used for very heavy lifting, as in tank recovery, shipbuilding, and offshore salvage operations. At dockyards they hoist masts and other substantial rigging parts on board. They are sometimes temporarily rigged on sailboats for similar tasks. Uses On land Shear legs are a lifting device related to the gin pole, derrick and tripod (lifting device). Shears are an A-frame of any kind of material such as timbers or metal, the feet resting on or in the ground or on a solid surface which will not let them move and the top held in place with guy-wires or guy ropes simply called "guys". Shear legs only need two guys whereas a gin pole needs at least three. The U. S. Army Fiel ...
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M32-ARV-HVSS-latrun-1
M3, M-3 or M03 may refer to: Computing and electronics * Intel m3, a brand of microprocessors * M.3 (aka NF1/NGSFF), a specification for internally mounted expansion cards * Leica M3, a landmark 35mm rangefinder camera * Modula-3 (M3), a programming language * M3, a British peak programme meter standard used for measuring the volume of audio broadcasts * m3, a macro processor for the AP-3 minicomputer, the predecessor to m4 * M3, a surface-mount version of the 1N4003 general-purpose silicon rectifier diode * M3 (email client), an unreleased email client for the Vivaldi browser Entertainment * M3, a comic book created by Vicente Alcazar * M3 adapter, a Game Boy Advance movie player * M3 (Canadian TV channel), a music and entertainment television channel * M3 (Hungarian TV channel), a Hungarian television channel * '' M3: Malay Mo Ma-develop'', a 2010 Philippine TV series * M3 Music Card, a 2007 flash-based MP3 player * M3 Perfect, M3 Simply and M3 Real, Nintendo DS and ...
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Guy (sailing)
A guy (probably from Dutch ''gei'', " brail") is a line (rope) attached to and intended to control the end of a spar on a sailboat. On a modern sloop-rigged sailboat with a symmetric spinnaker, the spinnaker pole is the spar most commonly controlled by one or more guys. Types There are two primary types of guys used to control a spinnaker pole: *The afterguy, working guy, or simply guy and sometimes known as a brace is attached to the windward clew of the spinnaker, and runs through the jaws on the outboard end of the pole and back to the cockpit. The afterguy is used to rotate the outboard end of the pole around the mast in order to optimize the sail's effectiveness, depending on the direction of the wind. Because a spinnaker has two clews, there is always a second line identical to the afterguy attached to the leeward clew of the spinnaker. This is called the sheet and serves a slightly different function. When the boat jibes, the spinnaker pole will be moved from one ...
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Vertical Transport Devices
Vertical is a geometric term of location which may refer to: * Vertical direction, the direction aligned with the direction of the force of gravity, up or down * Vertical (angles), a pair of angles opposite each other, formed by two intersecting straight lines that form an "X" * Vertical (music), a musical interval where the two notes sound simultaneously * "Vertical", a type of wine tasting in which different vintages of the same wine type from the same winery are tasted * Vertical Aerospace, stylised as "Vertical", British aerospace manufacturer * Vertical Kilometer, a discipline of skyrunning * Vertical market, a market in which vendors offer goods and services specific to an industry Media * ''Vertical'' (1967 film), Soviet movie starring Vladimir Vysotsky * "Vertical" (''Sledge Hammer!''), 1987 television episode * ''Vertical'' (novel), 2010 novel by Rex Pickett * Vertical Entertainment, an American independent film distributor and production company * Vertical (publi ...
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Sailing Rigs And Rigging
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 sailin ...
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Sheerleg
A floating sheerleg (also: shearleg) is a floating water vessel with a Crane (machine), crane built on shear legs. Unlike other types of crane vessel, it is not capable of rotating its crane independently of its hull. There is a huge variety in sheerleg capacity. The smaller cranes start at around 50 tons in lifting capacity, with the largest being able to lift 10,000 tons. The bigger sheerlegs usually have their own propulsion system and have a large accommodation facility on board, while smaller units are floating Pontoon (boat), pontoons that need to be towed to their workplace by tugboats. Sheerlegs are commonly used for Marine salvage, salvaging ships, assistance in shipbuilding, Stevedore, loading and unloading large cargo into ships, and bridge building. They have grown considerably larger over the last decades due to a marked increase in vessel, cargo, and component size (of ships, offshore oil rigs, and other large fabrications), resulting in heavier lifts both during c ...
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Masting Sheer
A masting sheer, sheers, shears or masting crane is a specialised shipyard crane, intended for placing tall masts onto large sailing ships. " Sheers" is an old name for a fixed crane formed by one or two wooden beams, fixed at the base and supported by ropes. Ancient sailing ships did not require sheers to erect their masts, as they could be lifted into place by ropes and allowed to pivot around their feet. As ships became larger, their larger and heavier masts were no longer able to be handled in this way. A crane was needed, tall enough to lift the entire mast vertically and then lower it into the ship. By the 18th century, such sheers were a necessity in any large shipyard. As sheers are not required to move, they were often constructed as masonry towers, with wooden jib structures atop them. Few have survived intact, but some of the towers remain, having now lost their jibs. In the late 19th century, the increasing size and capacity of general harbour cranes began to overl ...
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Hulk (ship Type)
A hulk is a ship that is afloat, but incapable of going to sea. Hulk may be used to describe a ship that has been launched but not completed, an abandoned wreck or shell, or to refer to an old ship that has had its rigging or internal equipment removed, retaining only its buoyant qualities. The word hulk also may be used as a verb: a ship is "hulked" to convert it to a hulk. The verb was also applied to crews of Royal Navy ships in dock, who were sent to the receiving ship for accommodation, or "hulked". Hulks have a variety of uses such as housing, prisons, salvage pontoons, gambling sites, naval training, or cargo storage. In the days of sail, many hulls served longer as hulks than they did as functional ships. Wooden ships were often hulked when the hull structure became too old and weak to withstand the stresses of sailing. More recently, ships have been hulked when they become obsolete or when they become uneconomical to operate. Sheer hulk A sheer hulk (or shear hulk) wa ...
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Topping Lift
The topping lift (more rarely known as an uphaul) is a line which applies upward force on a boom on a sailboat. Part of the running rigging, topping lifts are primarily used to hold a boom up when the sail is lowered. This line would run from near the free end of the boom(s) forward to the top of the mast. The line may be run over a block at the top of the mast and down to the deck to allow it to be adjusted. For small booms, the topping lift may be run from end of the boom to the backstay or next mast aft. When the sail is raised again, the topping lift is loosened or removed. On sailboats used for racing, boom lift function is frequently incorporated into the boom vang system, to reduce the number of lines aloft. Allowing the vang to take this function also simplifies operation of the boat. On larger or older sailing vessels, lifts known as "quarter-lifts" run to the middle of the boom. When the sail is raised, the quarter-lift on the leeward side must be slack, otherwise i ...
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Martingale (rigging)
A dolphin striker (an older term for a martingale boom or simply a martingale; sometimes called a striker) is a small vertical or near vertical ancillary spar spanning between the bowsprit and martingale thereby redirecting the tension in the forward end of the martingale slightly more vertically. This vertical component is necessary to more effectively oppose the forestays' mostly upward tension on the forward end of the bowsprit than would be the case in the absence of the dolphin striker. Around 1813 some large sailing vessels experimented with double strikers: these had two downward-pointing spars forming an inverted ''V'' in the middle of the bowsprit. However, the practice was short-lived as it did not seem to provide any additional benefit. The dolphin striker's length was typically half the length of the spritsail yard or, when spreaders were used, the same length as one spreader. On a catamaran such as the Hobie 16 and the Tornado where the mast is stepped on a beam bet ...
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Block And Tackle
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads. The pulleys are assembled to form blocks and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded through the pulleys to provide mechanical advantage that amplifies the force applied to the rope. Hero of Alexandria described cranes formed from assemblies of pulleys in the first century. Illustrated versions of Hero's ''Mechanica'' (a book on raising heavy weights) show early block and tackle systems. Overview A block is a set of pulleys or sheaves mounted on a single frame. An assembly of blocks with a rope threaded through the pulleys is called tackle. The process of threading ropes or cables through blocks is called "reeving", and a threaded block and tackle is said to have been "rove". A block and tackle system amplifies the tension force in the rope to lift heavy loads. They are comm ...
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A-frame
An A-frame is a basic structure designed to bear a load in a lightweight economical manner. The simplest form of an A-frame is two similarly sized beams, arranged in an angle of 45 degrees or less, attached at the top, like an uppercase letter 'A'. These materials are often wooden or steel beams attached at the top by rope, welding, gluing, or riveting. A-frames can be used as-is, as part of shears, or set up in a row along a longitudinal beam for added stability, as in a saw horse. More complex structures will often have crossmembers connecting the A-frames at different angles,"A-frame" (2009). ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0). Oxford University Press. forming a truss. Other structures that use A-frames * A-frame house * A-frame hydroponics system * A-frame contour measuring spirit level * A frame camping tent * A-frame complex, a motif in chemistry * Folding ladder * Double wishbone suspension (cars) * Some suspension bridges * Some ...
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