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Polytarp Sails
''Polytarp sails'' refer to sails constructed from rectangular polyethylene tarpaulins. Home boat builders often favor these synthetic ''sheet'' sails because the materials are inexpensive and easy to assemble into functional, durable sails. Construction method The usual construction method involves * laying out the tarp material, * measuring the sail dimensions, * creating baselines from corner to corner, * placing double-faced carpet tape around the sail outline with sufficient rounding on selected edges to shape the sail, * placing a reinforcing rope along the inner edge of the tape, and * folding the taped overlap back over the rope to create the sail shape. The sail can be strengthened by adding reinforcing material to the corners and stitching around the edges of the sail. Adding grommets to the corners and edges will allow the sail to be attached to the mast and spars. Because these grommets are placed through doubled material and behind the reinforcing line inside the sai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, cups, jars, etc.). , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. Many kinds of polyethylene are known, with most having the chemical formula (C2H4)''n''. PE is usually a mixture of similar polymers of ethylene, with various values of ''n''. It can be ''low-density'' or ''high-density'' and many variations thereof. Its properties can be modified further by crosslinking or copolymerization. All forms are nontoxic as well as chemically resilient, contributing to polyethylene's popularity as a multi-use plastic. However, polyethylene's chemical resilience also makes it a long-lived and decomposition-resistant pollutant when disposed of improperly. Being a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarpaulin
A tarpaulin ( , ) or tarp is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with polyurethane, or made of plastics such as polyethylene. Tarpaulins often have reinforced grommets at the corners and along the sides to form attachment points for rope, allowing them to be tied down or suspended. Inexpensive modern tarpaulins are made from woven polyethylene; This material has become so commonly used for tarpaulins that people in some places refer to it colloquially as "poly tarp" or "polytarp". Uses Tarpaulins are used in many ways to protect persons and things from wind, rain, and sunlight. They are used during construction or after disasters to protect partially built or damaged structures, to prevent mess during painting and similar activities, and to contain and collect debris. They are used to protect the loads of open trucks and wagons, to keep wood piles dry, and for shelters such as tents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thousandth Of An Inch
A thousandth of an inch is a derived unit of length in a system of units using inches. Equal to of an inch, a thousandth is commonly called a thou (used for both singular and plural) or, particularly in North America, a mil (plural mils). The words are shortened forms of the English and Latin words for "thousand" ( in Latin). In international engineering contexts, confusion can arise because ''mil'' is a formal unit name in North America but ''mil'' or ''mill'' is also a common colloquial clipped form of millimetre. The units are considerably different: a millimetre is approximately 39 mils. Contexts of use The thou, or mil, is most commonly used in engineering and manufacturing in non-metric countries. For example, in specifying: * The thickness of items such as paper, film, foil, wires, paint coatings, latex gloves, plastic sheeting, and fibers ** For example, most plastic ID cards are about in thickness. ** Card stock thickness in the United States, where mils are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram
The gram (originally gramme; SI unit symbol g) is a Physical unit, unit of mass in the International System of Units (SI) equal to one thousandth of a kilogram. Originally defined in 1795 as "the absolute Mass versus weight, weight of a volume of pure water equal to Cube (algebra), the cube of the hundredth part of a metre [1 Cubic centimetre, cm3], and at Melting point of water, the temperature of Melting point, melting ice", the defining temperature (0 °C) was later changed to the temperature of maximum density of water (approximately 4 °C). Subsequent redefinitions agree with this original definition to within 30 Parts-per notation, parts per million (0.003%), with the maximum density of water remaining very close to 1 g/cm3, as shown by modern measurements. By the late 19th century, there was an effort to make the Base unit (measurement), base unit the kilogram and the gram a derived unit. In 1960, the new International System of Units defined a '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Meter
The square metre ( international spelling as used by the International Bureau of Weights and Measures) or square meter (American spelling) is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square with sides one metre in length. Adding and subtracting SI prefixes creates multiples and submultiples; however, as the unit is exponentiated, the quantities grow exponentially by the corresponding power of 10. For example, 1 kilometre is 103 (one thousand) times the length of 1 metre, but 1 square kilometre is (103)2 (106, one million) times the area of 1 square metre, and 1 cubic kilometre is (103)3 (109, one billion) cubic metres. SI prefixes applied The square metre may be used with all SI prefixes used with the metre. Unicode characters Unicode has several characters used to represent metric area units, but these are for compatibility with East Asian character encodings and are meant to be used in new documents. * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainsail
A mainsail is a sail rigged on the main mast (sailing), mast of a sailing vessel. * On a square rigged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. The sail's foot is normally attached to a Boom (sailing), boom. (In extremely heavy weather, the mainsail may be lowered, and a much smaller trysail hoisted in its place). Historical fore-and-aft rigs used a four-sided gaff rigged mainsail, sometimes setting a gaff topsail above it. Whereas once the mainsail was typically the largest sail, today the mainsail may be smaller than the jib or genoa; G. Prout & Sons, Prout Catamaran#History, catamarans typically have a Mast-aft rig, mainmast stepped further aft than in a standard sloop, so that the mainsail is much smaller than the foresail. Bermuda rig The modern Bermuda rig uses a triangular mainsail aft of the mast, closely coordinated with a jib for sailing upwind. A large overlapping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mizzen
The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the median line of a ship or boat. Its purposes include carrying sails, spars, and derricks, giving necessary height to a navigation light, look-out position, signal yard, control position, radio aerial, or signal lamp. Large ships have several masts, with the size and configuration depending on the style of ship. Nearly all sailing masts are guyed. Until the mid-19th century, all vessels' masts were made of wood formed from a single or several pieces of timber which typically consisted of the trunk of a conifer tree. From the 16th century, vessels were often built of a size requiring masts taller and thicker than from single tree trunks. On these larger vessels, to achieve the required height, the masts were built from up to four sections (also called masts). From lowest to highest, these were called: lower, top, topgallant, and royal masts. Giving the lower sections ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinnaker
A spinnaker is a sail designed specifically for sailing off the wind on courses between a Point of sail#Reaching, reach (wind at 90° to the course) to Point of sail#Running downwind, downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually nylon, and are often brightly colored. They may be designed to perform best as either a reaching or a running spinnaker, by the shaping of the panels and seams. They are attached at only three points and said to be ''flown''. Etymology Some dictionaries suggest that the origin of the word could be traced to the first boat to commonly fly a spinnaker, a yacht called ''Sphinx'', mispronounced as ''Spinx''. ''Spinnaker'' entry in The Concise Oxford Dictionary of English Etymology (1996). Oxford University PressAccording to encyclopedia.com Both retrieved on 20 July 2008. ''Sphinx'' first set her spinnaker in the Solent in 1865, and the first recorded use of the word was in 1866 in the Augu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sprit
The spritsail is a four-sided, fore-and-aft sail that is supported at its highest points by the mast and a diagonally running spar known as the sprit. The foot of the sail can be stretched by a boom or held loose-footed just by its sheets. A spritsail has four corners: the throat, peak, clew, and tack. The Spritsail can also be used to describe a rig that uses a spritsail. Historically, spritsails were the first European fore-and-aft rigs, appearing in Greco-Roman navigation in the 2nd century BC. The rig The luff of the sail is bound to the mast, but unlike the gaff rig where the head is bound to a spar, this rig supports the leech of the sail by means of a diagonal spar or spars named a sprit ( ). The forward end of the sprit spar is attached to the mast, with the after end of the sprit spar attached to the peak. The sprit is steadied and controlled from the deck by a pair of wire vangs ( ) attached to the peak of the sail. It is said to be the ancestor of the common gaf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lug Sail
The lug sail, or lugsail, is a fore-and-aft, four-cornered sail that is suspended from a spar, called a yard. When raised, the sail area overlaps the mast. For "standing lug" rigs, the sail may remain on the same side of the mast on both the port and starboard tacks. For "dipping lug" rigs, the sail is lowered partially or totally to be brought around to the leeward side of the mast in order to optimize the efficiency of the sail on both tacks. The lug sail is evolved from the square sail to improve how close the vessel can sail into the wind. Square sails, on the other hand, are symmetrically mounted in front of the mast and are manually angled to catch the wind on opposite tacks. Since it is difficult to orient square sails fore and aft or to tension their leading edges ( luffs), they are not as efficient upwind, compared with lug sails. The lug rig differs from the gaff rig, also fore-and-aft, whose sail is instead attached at the luff to the mast and is suspended from a spar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaff Rig
Gaff rig is a sailing rig (configuration of sails, mast and stays) in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar (pole) called the ''gaff''. Because of the size and shape of the sail, a gaff rig will have running backstays rather than permanent backstays. The gaff enables a fore-and-aft sail to be four sided, rather than triangular. A gaff rig typically carries 25 percent more sail than an equivalent Bermuda rig for a given hull design. A sail hoisted from a gaff is called a gaff-rigged sail. Description Gaff rig remains the most popular fore-aft rig for schooner and barquentine mainsails and other course sails, and spanker sails on a square rigged vessel are always gaff rigged. On other rigs, particularly the sloop, ketch and yawl, gaff rigged sails were once common but have now been largely replaced by the Bermuda rig sail, which, in addition to being simpler than the gaff rig, usually all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
