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
Red Sails in the Sunset (song) Red Sails in the Sunset (song) "Red Sails in the Sunset" is a popular song. Published in 1935, its music was written by Hugh Williams (pseudonym for Wilhelm Grosz) with lyrics by prolific songwriter Jimmy Kennedy. The song was inspired by the "red sails" of "Kitty of Coleraine", a yacht Kennedy often saw off the northern coast of Ireland and by his adopted town Portstewart, a seaside resort in County Londonderry. The title of the song provides the inspiration for the Red Sails Festival held annually in Portstewart, Northern Ireland. Kennedy wrote the song while staying in Portstewart. The song