In nautical parlance, the draft or draught of a sail refers to the amount and shape of curvature in a horizontal cross-section. [1] Any sail experiences a force from the prevailing wind just because it impedes the air's passage. A sail with draft also functions as an airfoil when set at an angle slightly greater than the angle of the wind, producing lift which then propels the vessel. [1]
The word "belly" is also used in reference to the draft of a sail (i.e. "More belly in the main sail.").
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice (iceboat) or on land over a chosen course, which is often part of a larger plan of navigation.
Apparent wind is the wind experienced by a moving object.
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach to downwind. 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.
Gaff rig is a sailing rig 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.
Running rigging is the rigging of a sailing vessel that is used for raising, lowering, shaping and controlling the sails on a sailing vessel—as opposed to the standing rigging, which supports the mast and bowsprit. Running rigging varies between vessels that are rigged fore and aft and those that are square-rigged.
Sail components include the features that define a sail's shape and function, plus its constituent parts from which it is manufactured. A sail may be classified in a variety of ways, including by its orientation to the vessel and its shape,. Sails are typically constructed out of flexible material that is shaped by various means, while in use, to offer an appropriate airfoil, according to the strength and apparent direction of the wind. A variety of features and fittings allow the sail to be attached to lines and spars.
Tacking or coming about is a sailing maneuver by which a sailing craft, whose next destination is into the wind, turns its bow toward and through the wind so that the direction from which the wind blows changes from one side of the boat to the other, allowing progress in the desired direction. Sailing vessels are unable to sail higher than a certain angle towards the wind, so "beating to windward" in a zig-zag fashion with a series of tacking maneuvers, allows a vessel to sail towards a destination that is closer to the wind than the vessel can sail directly.
A running backstay is a rigging component on a sailboat which helps support the mast. A running backstay runs from each lateral corner of the stern to the mast at the level where the forestay begins in the fractional rig. Because they are attached low on the mast, they can present a significant problem in an accidental gybe, as the boom hits the stay, with the possibility of breaking the boom, mast, or both.
In aeronautics, the relative wind is the direction of movement of the atmosphere relative to an aircraft or an airfoil. It is opposite to the direction of movement of the aircraft or airfoil relative to the atmosphere. Close to any point on the surface of an aircraft or airfoil, the air is moving parallel to the surface; but at a great distance from the aircraft or airfoil, the movement of the air can be represented by a single vector. This vector is the relative wind or the free stream velocity vector.
An asymmetrical spinnaker is a sail used when sailing between about 90 and 165 degrees from the angle of the wind. Also known as an "asym", "aspin", or "A-sail" it can be described as a cross between a genoa jib and a spinnaker. It is asymmetric like a genoa, but like a spinnaker, its luff is unstructured; its leading edge is allowed to float freely, unencumbered by an internal wire or hanks attaching it to a stay. Unlike a symmetric spinnaker, the asymmetric does not require a spinnaker pole, since it is fixed (tacked) to the bow or a bowsprit.
A sailing yacht, is a leisure craft that uses sails as its primary means of propulsion. A yacht may be a sail or power vessel used for pleasure, cruising, or racing. There is no standard definition, so the term applies here to sailing vessels that have a cabin with amenities that accommodate overnight use. To be termed a "yacht", as opposed to a "boat", such a vessel is likely to be at least 33 feet (10 m) in length and have been judged to have good aesthetic qualities. Sailboats that do not accommodate overnight use or are smaller than 30 feet (9.1 m) are not universally called yachts. Sailing yachts in excess of 130 feet (40 m) are generally considered to be superyachts.
High-performance sailing is achieved with low forward surface resistance—encountered by catamarans, sailing hydrofoils, iceboats or land sailing craft—as the sailing craft obtains motive power with its sails or aerofoils at speeds that are often faster than the wind on both upwind and downwind points of sail. Faster-than-the-wind sailing means that the apparent wind angle experienced on the moving craft is always ahead of the sail. This has generated a new concept of sailing, called "apparent wind sailing", which entails a new skill set for its practitioners, including tacking on downwind points of sail.
Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating frame of reference apply to windmill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, the actions of which are not adjusted to the wind. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article.
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.
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 Sun Odyssey 349 is a French sailboat that was designed by Marc Lombard Design for cruising and first built in 2014.
The Seaward 25 is an American trailerable sailboat that was designed by Nick Hake a cruiser and first built in 1984.
The MacGregor 19, also called the PowerSailer 19, is an American trailerable sailboat that was designed by Roger MacGregor as a cruiser and first built in 1992.
The Waszp is an Australian, single-handed, hydrofoiling sailboat that was designed by Andrew McDougall as a one-design racer for youth and adults, and first built in 2016.