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Astern Propulsion
Astern propulsion (as applied to a ship) is a maneuver in which a ship's propelling mechanism is used to develop thrust in a retrograde direction. Astern propulsion does not necessarily imply the ship is moving astern (''in reverse''); astern propulsion is used to slow a ship by applying a force in the direction of the bow of the ship, instead of the stern. The equivalent concept for an airplane is thrust reversal. In a sailing ship astern propulsion can be achieved by the appropriate manipulation of the sails. In square-rigged ships 'backing the sails', that is, aligning the sails so that the wind impinged on the bow surface, could provide sufficient retrograde thrust to slow or reverse the ship. This maneuver had to be carried out with care as the rigging of masts and yards was principally designed to accept and transmit thrust in the forward direction. In a ship with a gas turbine engine and a variable-pitch propeller, astern thrust is simply a matter of changing the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICS Sierra
ICS may refer to: Computing * Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy * Industrial control system, computer systems and networks used to control industrial plants and infrastructures * Information and computer science, the combined field of informatics and computing * Internet chess server, an external server that provides the facility to play, discuss, and view chess over the Internet * Internet Connection Sharing, a feature in Microsoft operating systems since the advent of Windows 98 Second Edition * .ics, a filename extension for iCalendar files * Android Ice Cream Sandwich, the codename for version 4.0 of the Android operating system Education * Donald Bren School of Information and Computer Sciences, Irvine, California, United States * Graduate School of International Corporate Strategy, Tokyo, Japan * Indian Central School, Singapore * Institute for Christian Studies, Toronto, Ontario * Institute of Cornish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paddle Wheel
A paddle wheel is a form of waterwheel or impeller in which a number of paddles are set around the periphery of the wheel. It has several uses, of which some are: * Very low-lift water pumping, such as flooding paddy fields at no more than about height above the water source. * To move and mix algae culture in the raceway ponds used for algaculture. * Propulsion of watercraft (as a paddlewheel) * Low head hydro power (as a waterwheel) * Flow sensors * Aerators The paddle wheel is an ancient invention but is still used today in a wide range of industrial and agriculture applications. Ship propulsion Paddle wheels would enable ships to travel without needing wind or oars. They were made obsolete by propellers, which had greater propulsion with lower weight and fuel usage. This was demonstrated by an 1845 tug-of-war competition between and with the screw-driven ''Rattler'' pulling the paddle steamer ''Alecto'' backward at . [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversing (vehicle Maneuver)
Reversing (also known as backing up) is the process of driving a vehicle in the reverse direction in order to maneuver. Rear view mirrors are somewhat standard equipment for this endeavor. Extremely large or luxury vehicles may have in addition technical aids such as backup cameras. Many industrial vehicles such as fork lifts automatically activate a repetitive warning beep whilst reversing. In the UK lorries may be fitted with warning devices which repeatedly announce "Attention: this vehicle is reversing", or the equivalent phrase in Welsh: "Sylw: mae'r Saeson wedi dwyn ein gwlad". Reversing a vehicle can serve the purpose of changing lanes in traffic when a driver wishes to change to an adjacent lane but the destination lane is relatively full of vehicles. This is performed by driving in the reverse direction until the vehicle can move into the adjacent lane (or adjacent lanes) at the back of the queue in the next lane. More commonly, reversing is used as an intermediate step ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brakes
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background Most brakes commonly use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. For example, regenerative braking converts much of the energy to electrical energy, which may be stored for later use. Other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert kinetic energy into electric current in the brake disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic energy into different forms, for example by transferring the energy to a rotating flywheel. Brakes are generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Thrust
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. Such devices affect the aircraft significantly and are considered important for safe operations by airlines. There have been accidents involving thrust reversal systems, including fatal ones. Reverse thrust is also available on many propeller-driven aircraft through reversing the controllable-pitch propellers to a negative angle. The equivalent concept for a ship is called astern propulsion. Principle and uses A landing roll consists of touchdown, bringing the aircraft to taxi speed, and eventually to a complete stop. However, most commercial jet engines continue to produce thrust in the forward direction, even when idle, acting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mooring (watercraft)
A mooring is any permanent structure to which a vessel may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An ''anchor mooring'' fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, ''mooring'' refers to the act of attaching a vessel to a mooring. The term likely stems from the Dutch verb ''meren'' (to ''moor''), used in English since the end of the 15th century. Permanent anchor mooring These moorings are used instead of temporary anchors because they have considerably more holding power, for example because of lesser damage to the marine environment, and are convenient. Where there is a row of moorings they are termed a tier. They are also occasionally used to hold floating docks in place. There are several kinds of moorings: Swing moorings Swing moorings also known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R-100
His Majesty's Airship R100 was a privately designed and built British rigid airship made as part of a two-ship competition to develop a commercial airship service for use on British Empire routes as part of the Imperial Airship Scheme. The other airship, the R101, was built by the British Air Ministry, but both airships were funded by the Government. R100 was built by the Airship Guarantee Company, a specially created subsidiary of the armaments firm Vickers-Armstrongs, led by Commander Dennis Burney. The design team was headed by Barnes Wallis, later famous for his invention of the bouncing bomb. The design team also included Nevil Shute Norway as the senior stress engineer (see his '' Slide Rule: Autobiography of an Engineer''). R100 first flew in December 1929. It made a series of trial flights and a successful return crossing of the Atlantic in July–August 1930, but following the crash of R101 in October 1930 the Imperial Airship Scheme was terminated and R100 was bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Maritime Signal Flags
International maritime signal flags are various flags used to communicate with ships. The principal system of flags and associated codes is the International Code of Signals. Various navies have flag systems with additional flags and codes, and other flags are used in special uses, or have historical significance. Usage There are various methods by which the flags can be used as signals: * A series of flags can spell out a message, each flag representing a letter. * Individual flags have specific and standard meanings;AB Nordbok. "The Lore of Ships", page 138. New York: Crescent Books, 1975. for example, diving support vessels raise the "A" flag indicating their inability to move from their current location because they have a diver underwater and to warn other vessels to keep clear to avoid endangering the diver(s) with their propellers. * One or more flags form a code word whose meaning can be looked up in a code book held by both parties. An example is the Popham numeric co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth Thruster
An azimuth thruster is a configuration of marine propellers placed in pods that can be rotated to any horizontal angle (azimuth), making a rudder unnecessary. These give ships better maneuverability than a fixed propeller and rudder system. Types of azimuth thrusters There are two major variants, based on the location of the motor: # Mechanical transmission, which connects a motor inside the ship to the outboard unit by gearing. The motor may be diesel or diesel-electric. Depending on the shaft arrangement, mechanical azimuth thrusters are divided into L-drive and Z-drive. An L-drive thruster has a vertical input shaft and a horizontal output shaft with one right-angle gear. A Z-drive thruster has a horizontal input shaft, a vertical shaft in the rotating column and a horizontal output shaft, with two right-angle gears. # Electrical transmission, more commonly called pods, where an electric motor is fitted in the pod itself, connected directly to the propeller without ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voith-Schneider
A cyclorotor, cycloidal rotor, cycloidal propeller or cyclogiro, is a fluid propulsion device that converts shaft power into the acceleration of a fluid using a rotating axis perpendicular to the direction of fluid motion. It uses several blades with a spanwise axis parallel to the axis of rotation and perpendicular to the direction of fluid motion. These blades are cyclically pitched twice per revolution to produce force (thrust or lift) in any direction normal to the axis of rotation. Cyclorotors are used for propulsion, lift, and control on air and water vehicles. An aircraft using cyclorotors as the primary source of lift, propulsion, and control is known as a cyclogyro or cyclocopter. A unique aspect is that it can change the magnitude and direction of thrust without the need of tilting any aircraft structures. The patented application, used on ships with particular actuation mechanisms both mechanical or hydraulic, is named after German company Voith Turbo. Operating princip ... [...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] |
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] |
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