Forces on sails to stay within the limitations of a craft's stability and power requirements, which are functions of hull (for boats) or chassis (for land craft) design. Sails derive power from wind that varies in time and with height above the surface. In order to do so, they are designed to adjust to the wind force for various points of sail. Both their design and method for control include means to match their lift and drag capabilities to the available apparent wind, by changing surface area, angle of attack, and curvature. Wind speed increases with height above the surface; at the same
Sails of the South Tipner Bridge. The Sails are illuminated in violet at night. In addition, there are bird roosting sites in nearby Tipner Lake. The sails of the south was part of the redundant but later revived gateway project, this and the refurbishment of the nearby bridge was the only parts of the project to be realised. The bridge intended to take the M275 over a roundabout of an unbuilt junction roundabout. In 2006 vandals smashed 21 of the 24 lights that light up the structure. As of 14/07/2015, they are yet to be fixed. Sails of the South The Trimast, commonly referred