A leeboard is a lifting foil used by a sailboat, much like a centerboard, but located on the leeward side of the boat. The leeward side is used so that the leeboard isn't lifted from the water when the boat heels, or leans under the force of the wind. Lift consists of the sum (technically the negative product) of all the fluid dynamic forces on a body normal (i. ... FOIL was the name for two different programming languages. ... A centreboard is a form of removable keel on a small sailing boat or dinghy which can be removed to lower the draught (or depth) of the vessel. ... Leeward is the side of a boat away from the direction where the wind is coming (i. ...

As nearly all sailboats tack to work their way upwind (with the exception of the proa), a boat utilizing a leeboard either needs to have two retractable leeboards, one on each side, or a method of removing the leeboard and attaching it to both sides while under way. While it is possible to leave two boards down, leeboards are designed so that the windward board isn't needed, and so it is retracted to reduce drag. Unlike centerboards, which are symmetric along the boat's axis, leeboards are often asymmetric, so they more efficiently provide lift in one direction only. Some fast racing scows use bilgeboards, which are mounted between the centerline of the hull and the sides, specifically so that they can use a pair of asymmetric foils for maximum lift and minimum drag. Tack is a term, that depending on its application has several different meanings. ... The Proa is a two hulled vessel with unequal parallel hulls, superficially similar to an outrigger canoe. ... Windward is the side of a boat into which the wind is blowing. ... For a solid object moving through a fluid or gas, drag is the sum of all the aerodynamic or hydrodynamic forces in the direction of the external fluid flow. ... A scow, in the original sense, is a flat bottomed boat, often used to haul garbage or similar bulk freight; cf. ... A bilgeboard is a lifting foil used in a sailboat, which resembles a cross between a centerboard and a leeboard. ...

Leeboards are not common in commercially built boats, because many people consider them inelegant and awkward (thus preventing them from being used in commercial boats, and perpetuating the cycle). They are far more common in home-built boats, especially stitch and glue sailboats. Leeboards simplify construction of the hull, as they are attached to the outside and do not require holes in the hull, which can leak. Since centerboards are retractable, they require a large, watertight trunk to hold them in place when retracted, and this occupies what otherwise might be useful space in the cabin or cockpit of the boat. Use of leeboards, while it adds complexity to the process of tacking, leaves the floor of the boat unobstructed. The stitch and glue method was developed by the first TV DIY expert, Barry Bucknell, in about 1964. ... A hull is the body or frame of a ship or boat. ... A cabin or cab is an enclosed space, in a ship, see cabin (ship), in an aircraft or spacecraft as a log cabin as in a hansom cab see also Uncle Toms Cabin This is a disambiguation page — a navigational aid which lists other pages that might otherwise share... Cockpit of a light aircraft, showing instrumentation dials and dual control yokes. ...

In the past, leeboards were used by relatively large inshore sailing vessels used for transport, such as Dutch barges and Thames barges. For these boats, leeboards provided the advantages of shallow draught for working close inshore and an unobstructed hold for cargo. They were also easier to build than a large centreboard would have been.