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Internal Drive Propulsion
Internal drive propulsion or water-jet propulsion is a form of marine propulsion used in recreational boating. Like other forms of motorized boating, internal drive propulsion employs a motor that turns a propeller to move the boat forward. The primary difference between internal drive boats and external drive boats is that the propeller is enclosed inside the hull of an internal drive boat whereas the propeller is exposed outside the hull of a stern drive, V-drive or straight shaft drive boat. A conventional screw propeller accelerates a large volume of water by a small amount, similar to the way an airplane propeller accelerates a large volume of air by a small amount. An aircraft's jet engine, by contrast, accelerates a smaller volume of air by a large amount. Both methods yield thrust due to Newton's third law — every force gives rise to an equal and opposite force. In an internal drive boat, pumping a small volume of water and accelerating it by a large amount deliver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Propulsion
Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems. Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfares. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boating
Boating is the leisurely activity of travelling by boat, or the recreational use of a boat whether Motorboat, powerboats, Sailing, sailboats, or man-powered vessels (such as rowing and paddle boats), focused on the travel itself, as well as sports activities, such as fishing or waterskiing. It is a popular activity, and there are millions of boaters worldwide. Types of boats Boats (boat types) can be categorized into 3 different types types of board categories, unpowered, motor boats, and sailboats.Recreational boats (sometimes called pleasure craft, especially for less sporting activities) fall into several broad categories, and additional subcategories. Broad categories include Dinghy, dinghies (generally under 16 feet (5 m) powered by sail, small engines, or muscle power) usually made from hardwood or inflatable rubber. paddle sports boats (Kayak, kayaks, rowing shells, Canoe, canoes), runabouts (15–25 ft. (5–8 m) powerboats with either outboard, sterndrive, or inboard ... [...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 (ship), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hull (watercraft)
A hull is the watertight body of a ship, boat, or flying boat. The hull may open at the top (such as a dinghy), or it may be fully or partially covered with a deck. Atop the deck may be a deckhouse and other superstructures, such as a funnel, derrick, or mast. The line where the hull meets the water surface is called the waterline. General features There is a wide variety of hull types that are chosen for suitability for different usages, the hull shape being dependent upon the needs of the design. Shapes range from a nearly perfect box in the case of scow barges to a needle-sharp surface of revolution in the case of a racing multihull sailboat. The shape is chosen to strike a balance between cost, hydrostatic considerations (accommodation, load carrying, and stability), hydrodynamics (speed, power requirements, and motion and behavior in a seaway) and special considerations for the ship's role, such as the rounded bow of an icebreaker or the flat bottom of a landing craft. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stern Drive
A sterndrive or inboard/outboard drive (I/O) is a form of marine propulsion which combines inboard power with outboard drive. The engine sits just forward of the transom (nautical), transom while the drive unit (outdrive or drive leg) lies outside the Hull (watercraft), hull. Operation The drive unit (outdrive) carries power from the inboard engine, typically mounted above the waterline, outboard through the transom and downward to the propeller below the waterline. The outdrive resembles the bottom half of an outboard motor and is composed of two sub-units: an upper containing a driveshaft connected through the transom to an engine which transmits power to a 90-degree-angle gearbox; and the lower containing a vertical driveshaft receiving power from the upper unit gearbox, transmitted through another 90-degree-angle gearbox to the propeller shaft. The boat is steered by pivoting the outdrive, as on an outboard motor; no rudder is needed. The outdrive is pivoted up for trailer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bill Hamilton (engineer)
Sir Charles William Feilden Hamilton (26 July 1899 – 30 March 1978) was a New Zealand engineer who developed the modern jetboat, and founded the water jet manufacturing company, CWF Hamilton Ltd. Hamilton never claimed to have invented the jet boat. He once said "I do not claim to have invented marine jet propulsion. The honour belongs to a gentleman named Archimedes, who lived some years ago." What he did was refine the design enough to produce the first useful modern jet boat. Early life Hamilton was born at Ashwick Station near Fairlie, New Zealand. Hamilton survived an airplane accident returning to Rongotai Airport (Wellington) in poor conditions on 19 February 1936. The collision with the anemometer mast took the starboard wing off the fastest 'plane in the country, the Miles Falcon Six he was travelling in, and pilot Malcolm "Mac" McGregor died in hospital. At the age of 21 he bought the 'Irishman Creek' sheep station in South Canterbury. After a trip to England b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the orientation of the ''net'' force acting on that object. The magnitude of an object's acceleration, as described by Newton's Second Law, is the combined effect of two causes: * the net balance of all external forces acting onto that object — magnitude is directly proportional to this net resulting force; * that object's mass, depending on the materials out of which it is made — magnitude is inversely proportional to the object's mass. The SI unit for acceleration is metre per second squared (, \mathrm). For example, when a vehicle starts from a standstill (zero velocity, in an inertial frame of reference) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the vehicle turns, an acc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
