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Jet Boat
A jetboat is a boat propelled by a jet of water ejected from the back of the craft. Unlike a powerboat or motorboat that uses an external propeller in the water below or behind the boat, a jetboat draws the water from under the boat through an intake and into a pump-jet inside the boat, before expelling it through a nozzle at the stern. The modern jetboat was developed by New Zealand engineer Sir William Hamilton in the mid-1950s. His goal was a boat to run up the fast-flowing rivers of New Zealand that were too shallow for propellers. Previous attempts at waterjet propulsion had very short lifetimes, generally due to the inefficient design of the units and the fact that they offered few advantages over conventional propellers. Unlike these previous waterjet developments, such as Campini's and the Hanley Hydrojet, Hamilton had a specific need for a propulsion system to operate in very shallow water, and the waterjet proved to be the ideal solution. The popularity of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TWC Waitoto River• Stewart Nimmo • MRD 0928
TWC may refer to: Organizations * Taiwan Water Corporation, a water utility company in Taiwan * Taylor Woodrow Construction, a British-based construction company, now part of Taylor Wimpey * Tech Workers Coalition, an international labor rights group seeking to organize the tech industry * Tennessee Wesleyan College, a liberal-arts college in Athens, Tennessee * Texas Workforce Commission, a governmental agency in the U.S. * Time Warner Cable, an American cable telecommunications company that existed from 1992 until its 2016 purchase by Charter Communications * Trans World Communications, the investment vehicle of businessman Owen Oyston * The Weather Company (Australian company), now known as Weatherzone, an Australian meteorological service provider * The Weinstein Company, an American film studio * Trans World Connection, an American former airline, affiliate of Trans World Airlines (TWA) Technology * Three-way catalyst, key component of catalytic converters Media * The Weather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littoral Combat Ship
The littoral combat ship (LCS) is either of two classes of relatively small surface vessels designed for operations near shore by the United States Navy. It was "envisioned to be a networked, agile, stealthy surface combatant capable of defeating anti-access and asymmetric threats in the littorals." Littoral combat ships are comparable to corvettes found in other navies. The and the are the first two LCS variants. Each is slightly smaller than the U.S. Navy's but larger than ''Cyclone''-class patrol ships. Each has the capabilities of a small assault transport, including a flight deck and hangar for housing two SH-60 or MH-60 Seahawk helicopters, a stern ramp for operating small boats, and the cargo volume and payload to deliver a small assault force with fighting vehicles to a roll-on/roll-off port facility. Standard armaments include Mk 110 57 mm guns and RIM-116 Rolling Airframe Missiles. They are also equipped with autonomous air, surface, and underwater vehicle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whirlpool Jet Boat Tours In Devil's Hole Rapids In Niagara River Gorge
A whirlpool is a body of rotating water produced by opposing currents or a current running into an obstacle. Small whirlpools form when a bath or a sink is draining. More powerful ones formed in seas or oceans may be called maelstroms ( ). ''Vortex'' is the proper term for a whirlpool that has a downdraft. In narrow ocean straits with fast flowing water, whirlpools are often caused by tides. Many stories tell of ships being sucked into a maelstrom, although only smaller craft are actually in danger. Smaller whirlpools appear at river rapids and can be observed downstream of artificial structures such as weirs and dams. Large cataracts, such as Niagara Falls, produce strong whirlpools. Notable whirlpools Saltstraumen Saltstraumen is a narrow strait located close to the Arctic Circle, south-east of the city of Bodø, Norway. It has one of the strongest tidal currents in the world. Whirlpools up to in diameter and in depth are formed when the current is at its strongest. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planing (sailing)
Planing ( ) is the mode of operation for a waterborne craft in which its weight is predominantly supported by hydrodynamic lift, rather than hydrostatic lift (buoyancy). Many forms of marine transport make use of planing, including fast ferries, racing boats, floatplanes, flying boats, seaplanes, and water skis. Most surfboards are planing or semi-planing hulls. Beyond planing, fast vessel designs have seen a transition to hydrofoil designs. History The earliest documented planing sailboat was a proa built in 1898 by Commodore Ralph Munroe. It was capable of speeds of more than twice the hull speed. Planing a sailing dinghy was first popularised by Uffa Fox in Britain. In 1928 Fox introduced planing to the racing world in his International 14 dinghy, ''Avenger''. That year he gained 52 first places, 2 seconds, and 3 third places out of 57 race starts. This performance was noticed by other designers who further developed them. Over the years many dinghies have acquired the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planing (sailing)
Planing ( ) is the mode of operation for a waterborne craft in which its weight is predominantly supported by hydrodynamic lift, rather than hydrostatic lift (buoyancy). Many forms of marine transport make use of planing, including fast ferries, racing boats, floatplanes, flying boats, seaplanes, and water skis. Most surfboards are planing or semi-planing hulls. Beyond planing, fast vessel designs have seen a transition to hydrofoil designs. History The earliest documented planing sailboat was a proa built in 1898 by Commodore Ralph Munroe. It was capable of speeds of more than twice the hull speed. Planing a sailing dinghy was first popularised by Uffa Fox in Britain. In 1928 Fox introduced planing to the racing world in his International 14 dinghy, ''Avenger''. That year he gained 52 first places, 2 seconds, and 3 third places out of 57 race starts. This performance was noticed by other designers who further developed them. Over the years many dinghies have acquired the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Etymology and usage For many centuries, the word "wing", from the Old Norse ''vængr'', referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofoil
A hydrofoil is a lifting surface, or foil, that operates in water. They are similar in appearance and purpose to aerofoils used by aeroplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains speed, the hydrofoils lift the boat's hull out of the water, decreasing drag and allowing greater speeds. Description The hydrofoil usually consists of a winglike structure mounted on struts below the hull, or across the keels of a catamaran in a variety of boats (see illustration). As a hydrofoil-equipped watercraft increases in speed, the hydrofoil elements below the hull(s) develop enough lift to raise the hull out of the water, which greatly reduces hull drag. This provides a corresponding increase in speed and fuel efficiency. Wider adoption of hydrofoils is prevented by the increased complexity of building and maintaining them. Hydrofoils are generally prohibitively more expensive than conventional watercraft above a certain disp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shotover Jet, Jet Boating The Shotover River Canyons, Queenstown, New Zealand
Shotover is a hill and forest in Oxfordshire, England. The hill is east of Oxford. Its highest point is above sea level. Early history The toponym may be derived from the Old English , meaning "steep slope". Shotover was part of the Wychwood royal forestSherwood & Pevsner, 1974, pp. 763–765 from around the period of the Domesday Book until 1660. It was also known as the Forest of Shotover. A hill figure is recorded as having once been carved on the hill. Antiquarian John Aubrey writes: :"On Shotover Hill ear Oxfordwas heretofore (not long before the Civil Wars, in the memory of man) the effigies of a Giant cut in the earth, as the White Horse by Ashbury Park" Shotover Road The road between London and Oxford used to pass over the top of Shotover Hill. The road was made into a turnpike under the 1719 Stokenchurch Turnpike Act. Shotover Park Shotover Park and garden were begun in about 1714 for James Tyrrell of Oakley. Tyrell died in 1718 and the house was completed by his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transom (nautical)
A transom is the vertical reinforcement which strengthens the stern of a boat. This flat termination of the stern is typically above the waterline. The term was used as far back as Middle English in the 1300s, having come from Latin ''transversus'' (transverse) via Old French ''traversain'' (set crosswise). The stern of a boat is typically vertical. It can be raked such that there is an overhang above the water, as at the bow. A reverse transom is angled from the waterline forwards. Transoms can be used to support a rudder, outboard motor, or as a swimming and access platform. Gallery File:The Bermuda cedar (Juniperus bermudiana) transom of Spirit of Bermuda, 2016.jpg, The Bermuda cedar transom of the Spirit of Bermuda File:Sea Scooter transom.jpg, Flat transom on a dinghy with mount points for a rudder. File:Coble on shore at Boulmer (2) - geograph.org.uk - 1381157.jpg, Raked transom with rudder mount points. File:CS 30 Sailboat Kelsea 0297.jpg, Reverse transom with rudder m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stator
The stator is the stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors or biological rotors. Energy flows through a stator to or from the rotating component of the system. In an electric motor, the stator provides a magnetic field that drives the rotating armature; in a generator, the stator converts the rotating magnetic field to electric current. In fluid powered devices, the stator guides the flow of fluid to or from the rotating part of the system. Design Motor stators are made either from iron/steel or from a printed circuit board (PCB). Originally applied to low-power applications, PCB stators can be lighter, smaller, and less noisy. One design embeds thin copper traces in the PCB stator that serve as the windings. The traces are interleaved with epoxy-glass laminates, that insulate each coil from its neighbors. An air core replaces the traditional iron core, saving space and weight, and allowing a smaller air gap. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impeller
An impeller or impellor is a rotor used to increase the pressure and flow of a fluid. It is the opposite of a turbine, which extracts energy from, and reduces the pressure of, a flowing fluid. In pumps An impeller is a rotating component of a centrifugal pump that accelerates fluid outward from the center of rotation, thus transferring energy from the motor that drives the pump to the fluid being pumped. The velocity achieved by the impeller transfers into pressure when the outward movement of the fluid is confined by the pump casing. An impeller is usually a short cylinder with an open inlet (called an eye) to accept incoming fluid, vanes to push the fluid radially, and a splined, keyed, or threaded bore to accept a drive shaft. It can be cheaper to cast an impeller and its spindle as one piece, rather than separately. This combination is sometimes referred to simply as the "rotor." Types Open impellers An open impeller has a hub with attached vanes and is mounted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton's Laws Of Motion
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows: # A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force. # When a body is acted upon by a force, the time rate of change of its momentum equals the force. # If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his '' Philosophiæ Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy''), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics. In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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