Sail in the context of "Mainmast"

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⭐ Core Definition: Sail

A sail is a tensile structure, which is made from fabric or other membrane materials, that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments, usually in a three- or four-sided shape.

A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack, its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the velocity of the sailing craft. Angle of attack is often constrained by the sailing craft's orientation to the wind or point of sail. On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil, generating propulsive force as air passes along its surface, just as an airplane wing generates lift, which predominates over aerodynamic drag retarding forward motion. The more that the angle of attack diverges from the apparent wind as a sailing craft turns downwind, the more drag increases and lift decreases as propulsive forces, until a sail going downwind is predominated by drag forces. Sails are unable to generate propulsive force if they are aligned too closely to the wind.

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Sail in the context of Ancient Greek engineering

Ancient Greek technology developed during the 5th century BC, continuing up to and including the Roman period, and beyond. Inventions that are credited to the ancient Greeks include the gear, screw, rotary mills, bronze casting techniques, water clock, water organ, the torsion catapult, the use of steam to operate some experimental machines and toys, and a chart to find prime numbers. Many of these inventions occurred late in the Greek period, often inspired by the need to improve weapons and tactics in war. However, peaceful uses are shown by their early development of the watermill, a device which pointed to further exploitation on a large scale under the Romans. They developed surveying and mathematics to an advanced state, and many of their technical advances were published by philosophers, like Archimedes and Heron.

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Sail in the context of Canvas

Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags, electronic device cases, and shoes. It is popularly used by artists as a painting surface, typically stretched across a wooden frame.

Although historically made from hemp, modern canvas is usually made of cotton, linen, or sometimes polyvinyl chloride (PVC). It differs from other heavy cotton fabrics, such as denim, in being plain weave rather than twill weave. Canvas comes in two basic types: plain and duck. The threads in duck canvas are more tightly woven. The term duck comes from the Dutch word for cloth, doek. In the United States, canvas is classified in two ways: by weight (ounces per square yard) and by a graded number system. The numbers run in reverse of the weight so a number 10 canvas is lighter than number 4.

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Sail in the context of Sailboat

A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.

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Sail in the context of Sailing ship

A sailing ship is a sea-going vessel that uses sails mounted on masts to harness the power of wind and propel the vessel. There is a variety of sail plans that propel sailing ships, employing square-rigged or fore-and-aft sails. Some ships carry square sails on each mast—the brig and full-rigged ship, said to be "ship-rigged" when there are three or more masts. Others carry only fore-and-aft sails on each mast, for instance some schooners. Still others employ a combination of square and fore-and-aft sails, including the barque, barquentine, and brigantine.

Early sailing ships were used for river and coastal waters in ancient Egypt and the Mediterranean. The Austronesian peoples developed maritime technologies that included the fore-and-aft crab-claw sail and with catamaran and outrigger hull configurations, which enabled the Austronesian expansion into the islands of the Indo-Pacific. This expansion originated in Taiwan c. 3000 BC and propagated through Island Southeast Asia, reaching Near Oceania c. 1500 BC, Hawaii c. 900 AD, and New Zealand c. 1200 AD. The maritime trading network in the Indo-Pacific dates from at least 1500 BC. Later developments in Asia produced the junk and dhow—vessels that incorporated features unknown in Europe at the time.

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Sail in the context of Burj al Arab

The Jumeirah Burj Al Arab (Arabic: برج العرب, lit.'Arab Tower'), commonly known as Burj Al Arab, is a luxury hotel in Dubai, United Arab Emirates. Developed and managed by Jumeirah, it is one of the tallest hotels in the world, although 39% of its total height is made up of non-occupiable space. Burj Al Arab stands on an artificial island that is 280 m (920 ft) from Jumeirah Beach and is connected to the mainland by a private curving bridge. The shape of the structure is designed to resemble the sail of a dhow. It has a helipad near the roof, at a height of 210 m (689 ft) above ground.

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Sail in the context of List of ancient watermills

This list of ancient watermills presents an overview of water-powered grain-mills and industrial mills in classical antiquity, including the Hellenistic period through the Roman period up until circa 500 AD.

The water wheel and watermill are the earliest instances of machines harnessing natural forces to replace human muscular labour (apart from the sail). As such, it holds a special place in the history of technology and also in economic studies where it is associated with growth.

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Sail in the context of Longship

Longships (Old Norse: langskip) were long clinker-built warships (Old Norse: herskip, Old Swedish: hærskip) propelled by oars, and later also by sail, used by the Norse and surrounding Germanic tribes from at least the 4th century AD and throughout the Viking Age, being part of the Nordic ship building tradition. As the name suggests, they were long slender ships, intended for speed, with the ability to carry a large crew of warriors. They are sometimes called "dragonships" (Old Norse: drekaskip) due to a tradition of the fore and aft ends being decorated with a raised dragonhead (Old Norse: drekahofud) and tail respectively, with the sail making up the "wing" of the dragon. The largest types were thus called "dragons" (dreki), while smaller types had names such as karve (karfi), snekke (snekkja), and skeid (skeið).

Archaeological finds have been made of longships from the 9th, 10th and 11th centuries in Denmark, Norway and Germany, with motifs on Gotlandic picture stones dating to the 8th century or earlier. It is thought that the Norse specifically invented the design for Viking usage, which included raiding and warfare, exploration and commerce. The longship is a rather distinctly Norse (Scandinavian) construction, with bronze age petroglyphs in Sweden indicating a long tradition of building long animal-headed naval ships in Scandinavia. Equivalent clinker-built naval ships by the Wends (a South Baltic Slavic people) were much smaller and shorter in comparison.

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