1.
Sailing
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Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice or on land over a chosen course, which is often part of a larger plan of navigation. A course defined with respect to the wind direction is called a point of sail. Conventional sailing craft cannot derive power from sails on a point of sail that is too close into the wind, on a given point of sail, the sailor adjusts the alignment of each sail with respect to the apparent wind direction to mobilize the power of the wind. In the 21st century, most sailing represents a form of recreation or sport, recreational sailing or yachting can be divided into racing and cruising. Cruising can include extended offshore and ocean-crossing trips, coastal sailing within sight of land, until the end of the 19th century, sailing ships were the primary means for marine commerce. The earliest representation of a ship under sail appears on a painted disc found in Kuwait dating between 5000 and 5500 BCE, polynesian oceanfarers traveled vast distances of open ocean in outrigger canoes using navigation methods such as stick charts. Advances in sailing technology from the Middle Ages onward enabled Arab, Chinese, Indian and European explorers to make longer voyages into regions with extreme weather and climatic conditions. There were improvements in sails, masts and rigging, improvements in marine navigation including the tree and charts. Sailing has contributed to many great explorations in the world, the air interacting with the sails of a sailing vessel creates various forces, including reaction forces. If the sails are properly oriented with respect to the wind, however, boats propelled by sails cannot sail directly into the wind. They must tack back and forth in order to progress directly upwind, sails are airfoils that work by using an airflow set up by the wind and the motion of the boat. Sails work in two modes to use the wind to force, PUSH, when the boat is going in the same direction as the wind. The force on the sail is mostly aerodynamic drag, and sails acting in this way are aerodynamically stalled. This force manifests itself as pressure differences between the two sides of the sail - there is a region of low pressure on the front side of the sail and a region of high pressure on the back. Another way to say this is that sails generate lift using the air flows around them in the same way as an aircraft wing. The wind that a boat experiences is the combination of the true wind and this combination is the apparent wind, which is the relative velocity of the wind relative to the boat. When sailing upwind the apparent wind is greater than the true wind, iceboats can typically sail at 5 times the speed of the wind. Where there is a difference in motion, then there is energy to be extracted at the interface, the sailboat does this by placing the sail in the air and the hull in the water
2.
Ice boat
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An ice boat is a boat or purpose-built framework similar in functional design to a sail boat but fitted with skis or runners and designed to run over ice instead of through water. Ice yachting is the sport of sailing and racing iceboats, sail-able ice is known in the sport as hard water versus sailing on liquid or soft water. A related sport, land sailing, utilizes a configuration with a fuselage or frame equipped with wheels instead of runners. Iceboats commonly used for racing are usually only for one person, on some boats, a side car can be fitted to take others along for a ride. Traditional iceboats from before the late 19th century were used for transportation of goods and these boats reached lengths of 30 to 50 feet and were sometimes transported between sites on rail cars. Ice sailing was first developed in Europe, in America, it was done in several locations where the sport also continues today. Some of the older large stern steerer iceboats can seat several in their baskets, several of these boats are maintained and raced today. The Northwest Ice Yacht Association sponsors an annual regatta that includes classes for these boats and this annual regatta recently celebrated its 100th anniversary. The first iceboat in America is attributed to Oliver Booth in 1790 at Poughkeepsie and this craft was a small triangular box with two runners affixed to the front and a steering runner at the rear. One unique type of ice boat has its history in wide, stubby, scow-like vessels used in the 1800s, often for transportation across a mixed passage transitioning over sea-ice, wildly sailed by adjusting main and jib sail trim only, these boats had no rudder. Parallel rails were mounted on the bottom, like multiple sled runners, in 1869, one of the largest ice yachts ever was built for racing on the frozen Hudson River, called the Icicle. That boat occasionally raced the railroad which ran alongside the Hudson and these early ice sailing vessels led to the development of boats designed strictly for racing on ice. These stern-steerer iceboats were generally rigged as sloops, with a jib forward of the mast. This boat led to the Skeeter class, and the Skeeter Ice Boat Club formed on Geneva Lake, the Skeeter class adopted the logo of a mosquito on their sail, and has evolved into a very efficient aerodynamically clean machine. While the large stern-steerers could have up to 600 square feet of sail, in 1937, The Detroit News sponsored a new home-buildable ice boat design, which became the International DN. In 1968 Dick Slates of Pewaukee, Wisconsin designed and built the Nite with two wooden prototypes, the design was refined and fiberglass production began in 1970. Modern iceboats designs are generally supported by three skate blades called runners supporting a triangular or cross-shaped frame with the runner in front. Once the lateral force has been countered by the runner edge
3.
Land sailing
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Land sailing, also known as sand yachting or land yachting, is the act of moving across land in a wheeled vehicle powered by wind through the use of a sail. The term comes from analogy with sailing, historically, land sailing was used as a mode of transportation or recreation. Since the 1950s, it has evolved primarily into a racing sport, vehicles used in sailing are known as sail wagons, sand yachts, or land yachts. They typically have three wheels and function much like a sailboat, except that they are operated from a sitting or lying position, Land sailing works best in windy flat areas, and races often happen on beaches, airfields, and dry lake beds in desert regions. Modern land sailors, generally known as pilots, can go three to four times faster than the wind speed, a gust of wind is considered more beneficial in a land sailing race than a favorable windshift. A similar sport, known as ice yachting, is practiced on frozen lakes, another variation is the Whike, which combines land sailing with bicycling and can therefore also be used in everyday traffic because it does not fully depend on wind. He wrote that Gaocang Wushu invented a wind-driven carriage which was able to carry thirty people at once, there was another built in about 610 for the Emperor Yang of Sui, as described in the Continuation of the New Discourses on the Talk of the Times. European travelers from the 16th century onwards mentioned sailing carriages with surprise, in 1585, Gonzales de Mendoza wrote that the Chinese had many coaches and wagons mounted with sails, and even depicted them in artwork of silk hanfu robes and on earthenware vessels. In the 1584 atlas Theatrum Orbis Terrarum written by the cartographer Abraham Ortelius, there are large Chinese carriages depicted with sails and masts. Likewise, there are the same Chinese vehicles with sails depicted in the Atlas of Gerardus Mercator, the English poet John Milton popularized the Chinese sailing carriage in Europe with a poem written in 1665. In the 1860s, windwagons were used to transport across the American great plains, the precursor to the modern land yacht was invented in the summer of the year 1600 by the Flemish scientist Simon Stevin in Flanders as a commission for Prince Maurice of Orange. It was used by Prince Maurice for entertaining his guests, in 1898, the Dumont brothers of De Panne, Belgium, developed a land yacht whose sails were based on contemporary Egyptian sailboats used on the Nile River. Louis Blériot, the French aviation pioneer was instrumental in developing landsailing as a sport and it was viewed as an alternative sport when strong winds would have made flying in early aircraft too dangerous. Bleriots landsailers were first tried on the Buc airstrip, bleriot machines gave their best on Channel and North Sea wide and windy beaches at low tide. The Blériot firm coined the name aéroplage and even registered it as a trademark, the first races were held on the beaches of Belgium and France in 1909. Land yachts were used in the late 19th century and early 20th century to transport goods on dry lakes in America. The modern land yacht, a four-wheeled polyester/fibreglass and metal cart, often with a wing-mast, in 1967 a French Foreign Legion officer organized a land yacht race across the Sahara Desert. The story made the cover of National Geographic in November 1967, a reenactment of this event took place three years later and was filmed by National Geographic
4.
Sailboat
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A sailboat or sailing boat is a boat propelled partly or entirely by sails smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region, although sailboat terminology has varied across history, many terms have specific meanings in the context of modern yachting. A great number of sailboat-types may be distinguished by size, hull configuration, keel type, purpose, number and configuration of masts, and sail plan. Once a common racing configuration, today it gives versatility to cruising boats, a catboat has a single mast mounted far forward and does not carry a jib. Most modern designs have only one sail, the mainsail, however, a dinghy is a type of small open sailboat commonly used for recreation, sail training, and tending a larger vessel. They are popular in youth sailing programs for their short LOA, simple operation and they have three sails, the mainsail, jib, and spinnaker. Ketches are similar to a sloop, but there is a shorter mast astern of the mainmast. The second mast is called the mizzen mast and the sail is called the mizzen sail, a ketch can also be Cutter-rigged with two head sails. A schooner has a mainmast taller than its foremast, distinguishing it from a ketch or a yawl, a schooner can have more than two masts, with the foremast always lower than the foremost main. Traditional topsail schooners have topmasts allowing triangular topsails sails to be flown above their gaff sails, the most common modern sailboat is the sloop, which features one mast and two sails, typically a Bermuda rigged main, and a headsail. This simple configuration is very efficient for sailing into the wind, a smaller headsail is easier for a short-handed crew to manage. A yawl is similar to a ketch, with a mizzen mast carried astern the rudderpost more for balancing the helm than propulsion. Traditional sailboats are monohulls, but multi-hull catamarans and trimarans are gaining popularity, monohull boats generally rely on ballast for stability and usually are displacement hulls. This stabilizing ballast can, in boats designed for racing, be as much as 50% of the weight of the boat and it creates two problems, one, it gives the monohull tremendous inertia, making it less maneuverable and reducing its acceleration. Secondly, unless it has built with buoyant foam or air tanks, if a monohull fills with water. Multihulls rely on the geometry and the stance of the multiple hulls for their stability. Indeed, multihulls are designed to be as light-weight as possible and this absence of ballast also results in some very real performance gains in terms of acceleration, top speed, and maneuverability. The lack of ballast makes it easier to get a multihull on plane, reducing its wetted surface area and thus its drag. The absence of drag improves wind precision
5.
Sailing ship
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A modern sailing ship or sailship is any large wind-powered vessel. Traditionally a sailing ship is a vessel that carries three or more masts with square sails on each. Large sailing vessels that are not ship-rigged may be more referred to by their sail rig, such as schooner, barque, brig. There are many different types of sailing ships, but they all have certain basic things in common, every sailing ship has a hull, rigging and at least one mast to hold up the sails that use the wind to power the ship. The crew who sail a ship are called sailors or hands and they take turns to take the watch, the active managers of the ship and her performance for a period. Watches are traditionally four hours long, some sailing ships use traditional ships bells to tell the time and regulate the watch system, with the bell being rung once for every half hour into the watch and rung eight times at watch end. A severe storm could lead to shipwreck, and the loss of all hands, Sailing ships are limited in their maximum size compared to ships with heat engines, so economies of scale are also limited. The heaviest sailing ships never exceeded 14,000 tons displacement, there are many types of sailing ships, mostly distinguished by their rigging, hull, keel, or number and configuration of masts. There are also types of smaller sailboats not listed here. The steam power was used to drive the winches, hoists, a similar ship Kruzenshtern, a very large sailing vessel without mechanical assists, had a crew of 257 men, compared to the Preussen, which required only 48 men. In 2006, automated control had been taken to the point where sails could be operated by one using a central control unit. The DynaRig technology was first developed in the 1960s in Germany by W. Prolls as an alternative for commercial ships to prepare for a possible future energy crisis. The technology is a version of the same type of sail used by the Preussen. The main difference is that the yards do not swing around a fixed mast but are attached to a rotating mast. DynaRig along with extensive computerization was used in the proof-of-concept Maltese Falcon to enable it to be sailed with no crew aloft, as of 2013, with increasing restrictions on use of bunker fuel, attempts were underway to develop hybrid sailing ships using automated sail and alternative fuels. Tall ship Rigging Sail-plan List of large sailing vessels Cruising Shipbuilding, the History of a Ship from Her Cradle to Her Grave, With a Short Account of Modern Steamships and Torpedoes. The sailing-ship, six years of history. Media related to Sailing ships at Wikimedia Commons
6.
Apparent wind
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Apparent wind is the wind experienced by a moving object. The Apparent wind is the experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. Apparent wind velocity is the sum of the true wind. In sailing, the apparent wind is the flow of air acting upon a sail. It is the wind as it appears to the sailor on a moving vessel and it differs in speed and direction from the true wind that is experienced by a stationary observer. In nautical terminology, these properties of the apparent wind are normally expressed in knots, on boats, apparent wind is measured or felt on face / skin if on a dinghy or looking at any telltales or wind indicators on board. True wind needs to be calculated or stop the boat and this must be corrected for when converting apparent wind angle to true wind direction. The same effect is found when the boat is altering course, modern instrumentation can calculate the true wind velocity when the apparent wind and boat velocity and direction are input. In sailboat racing, and especially in speed sailing, apparent wind is a vital factor, a vessel traveling at increasing speed relative to the prevailing wind will encounter the wind driving the sail at a decreasing angle and increasing velocity. Eventually, the drag and diminished degree of efficiency of a sail at extremely low angles will cause a loss of accelerating force. This constitutes the main limitation to the speed of wind-driven vessels, windsurfers and certain types of boats are able to sail faster than the true wind. These include fast multihulls and some planing monohulls, ice-sailors and land-sailors also usually fall into this category, because of their relatively low amount of drag or friction. In the foiling AC72 Americas cup catamarans, the boats sail through the water at up to double the wind strength. The effect of this is to change the apparent wind direction when sailing downwind. In these boats the forward speed is so great that the apparent wind is always forward—at an angle that varies between 2 and 4 degrees to the wing sail. This means that AC72s are effectively tacking downwind, although at a greater angle than the normal 45-degree upwind angle, in fixed-wing aircraft, apparent wind is what is experienced on board, and it determines the necessary speeds for take-off and landing. Aircraft carriers generally steam directly upwind at maximum speed, in order to increase apparent wind, land-based airport traffic, as well as most mid-sized and large birds generally take off and land facing upwind for the same reason. For port apparent winds, the true pointing angle has the sign, α = − arccos = − arccos Navigational Algorithms Apparent wind soft, math, vector solution
7.
Forces on sails
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Similar principles in a rotating frame of reference apply to wind mill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article. Forces on sails depend on speed and direction and the speed. The direction that the craft is traveling with respect to the wind is called the point of sail. The speed of the craft at a point of sail contributes to the apparent wind—the wind speed. Depending on the alignment of the sail with the apparent wind, for apparent wind angles aligned with the entry point of the sail, the sail acts as an airfoil and lift is the predominant component of propulsion. For apparent wind angles behind the sail, lift diminishes and drag increases as the predominant component of propulsion, because of limitations on speed through the water, displacement sailboats generally derive power from sails generating lift on points of sail that include close-hauled through broad reach. This knowledge is applied to the design of sails in such a manner that sailors can adjust sails to the strength, the combination of a sailing crafts speed and direction with respect to the wind, together with wind strength, generate an apparent wind velocity. A component of this lift pushes the craft crosswise to its course, which is resisted by a sailboats keel, an important component of lift is directed forward in the direction of travel and propels the craft. To understand forces and velocities, discussed here, one must understand what is meant by a vector, velocity, denoted as boldface in this article, is an example of a vector, because it implies both direction and speed. The corresponding speed, denoted as italics in this article is a scalar value, likewise, a force vector, F, denotes direction and strength, whereas its corresponding scalar denotes strength alone. Graphically, each vector is represented with an arrow that shows direction, vectors of consistent units may be added and subtracted, graphically, by positioning tips and tails of the arrows, representing the input variables and drawing the resulting derived vector. Pressure differences result from is the force per unit area on the sail from the air passing around it. The lift force results from the pressure on the windward surface of the sail being higher than the average pressure on the leeward side. These pressure differences arise in conjunction with the air flow. To generate lift, a sail must present an angle of attack between the line of the sail and the apparent wind velocity. Angle of attack is a function of both the point of sail and how the sail is adjusted with respect to the apparent wind. As the lift generated by a sail increases, so does lift-induced drag, sails with the apparent wind behind them operate in a stalled condition
8.
Course (navigation)
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In navigation, a vessels or aircrafts course is the compass direction along which the vessel or aircraft is to be steered. It is to be distinguished from the vessel or aircrafts heading, the line connecting the objects consecutive positions on the ground is referred to as the ground track. The track the object was intended to follow is called the route, for ships and aircraft, the route is represented by the great circle line that connects the previous waypoint with the next waypoint. The responsibility of a navigator is to make the track coincide as much as possible with the route, the direction of the route is called the route course. Course exceptionally, and arguably erroneously, may refer to the route, such as in a course deviation indicator, in which case it no longer constitutes an angle. The direction of the circle line that runs from the current position to the next waypoint is called the course to steer. The tracking angle is the angle between the course to steer and the course, the heading is the direction to which the nose of the object is pointing, its orientation. Directions are typically measured clockwise from north, either true or magnetic, in degrees from 0° to 359°, in aviation, north is usually expressed as 360° instead of 0°. For land based vehicles, heading and course are typically identical, but for aircraft the action of wind, heading is the angle between the direction in which the objects nose is pointing and a reference direction. Deviation only depends on the vehicles own magnetic field and the heading, the compass heading has to be corrected first for deviation, which yields the magnetic heading. Correcting this for variation yields true heading, an aircrafts heading is the direction that the aircrafts nose is pointing. It is referenced by using either the magnetic compass or heading indicator, using standard instrumentation, it is in reference to the local magnetic north direction. True heading is in relation to the lines of meridian, the units are degrees from north in a clockwise direction. North is 0°, east is 90°, south is 180°, note that, due to wind forces, the direction of movement of the aircraft, or track, is not the same as the heading. The nose of the aircraft may be pointing due west, for example, the angle between heading and track is known as the drift angle. Crab angle is the amount of correction an aircraft must be turned into the wind in order to maintain the desired course and it is opposite in direction to the drift angle and approximately equal in magnitude for small angles. An aircraft can have instruments on board that show to the pilot the aircraft heading, the autopilot can be programmed to maintain either the aircraft heading or its course. In the event of a headwind or tailwind, heading and course in an aircraft are the same, for a ship at sea, if a current is running parallel to the heading, then the course is the same as the heading
9.
Wind direction
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Wind direction is reported by the direction from which it originates. For example, a wind blows from the north to the south. Wind direction is reported in cardinal directions or in azimuth degrees. Wind direction is measured in degrees clockwise from due north and so a wind coming from the south has a direction of 180 degrees. A variety of instruments can be used to wind direction, such as the windsock. Both of these work by moving to minimize air resistance. The way a weather vane is pointed by prevailing winds indicates the direction from which the wind is blowing. The larger opening of a windsock faces the direction that the wind is blowing from, its tail, with the smaller opening, modern instruments used to measure wind speed and direction are called anemometers and wind vanes, respectively. These types of instruments are used by the energy industry. In situations where modern instruments are not available, a finger can be used to test the direction of wind. This is accomplished by wetting the finger and pointing it upwards, the side of the finger that feels cool is the direction from which the wind is blowing. The same principle is used to measure the dew point using a sling psychrometer, another primitive technique for measuring wind direction is to take a pinch of grass and drop it, the direction that the grass falls is the direction the wind is blowing. This last technique is used by golfers because it allows them to gauge the strength of the wind as well. Yamartino method for calculating the standard deviation of wind direction Apparent wind Weather vane Wind power Air masses
10.
Rigging
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According to the Encyclopædia Britannica Eleventh Edition rigging derives from Anglo-Saxon wrigan or wringing, to clothe. The same source points out that rigging a sailing vessel refers to putting all the components in place to allow it to function, including the masts, spars, sails and the rigging. Rigging is divided into two classes, standing, which supports the mast, and running, which controls the orientation of the sails, configurations differ for each type of rigging, between fore-and-aft rigged vessels and square-rigged vessels. Standing rigging is cordage which is fixed in position, standing rigging is almost always between a mast and the deck, using tension to hold the mast firmly in place. Due to its role, standing rigging is now most commonly made of steel cable and it was historically made of the same materials as running rigging, only coated in tar for added strength and protection from the elements. Most fore-and-aft rigged vessels have the types of standing rigging, a forestay, a backstay. Less common rigging configurations are diamond stays and jumpers, both of these are used to keep a thin mast in column especially under the load of a large down wind sail or in strong wind. Rigging parts include swageless terminals, swage terminals, shackle toggle terminals, whereas 20th-Century square-rigged vessels were constructed of steel with steel standing rigging, prior vessels used wood masts with hemp-fiber standing rigging. This construction relied heavily on support by an array of stays. Each stay in either the fore-and-aft or athwartships direction had a one in the opposite direction providing counter-tension. Fore-and-aft the system of tensioning started with the stays that were anchored at in front each mast, each additional mast segment is supported fore and aft by a series of stays that led forward. These lines were countered in tension by backstays, which were secured along the sides of the vessel behind the shrouds, running rigging is the cordage used to control the shape and position of the sails. Materials have evolved from the use of Manilla rope to synthetic fibers, running rigging varies between fore-and-aft rigged vessels and square-rigged vessels. They have common functions between them for supporting, shaping and orienting sails, which different mechanisms. For supporting sails, halyards, are used to raise sails, on gaff-riged vessels, topping lifts hold the yards across the top of the sail aloft. Sail shape is controlled by lines that pull at the corners of the sail, including the downhaul at the clew. The orientation of sails to the wind is controlled primarily by sheets, but also by braces, full rigged ship Lateen rig Shipbuilding Superstructure Harland, John. Seamanship in the Age of Sail, the Masting and Rigging of English Ships of War, 1625–1860
