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 Silver Sails of Silver Sails of Silver is an album by British folk rock band Steeleye Span. The album was produced two years after the band's ostensible break-up. At the request of Chrysalis Records Peter Knight and Bob Johnson both returned, replacing their own replacements Martin Carthy and John Kirkpatrick, who departed after the release of "Live at Last". Despite being produced by Elton John's producer Gus Dudgeon, "Sails of Silver" was a commercial failure, and this proved a final straw for Tim Hart, who departed the band, leaving Maddy Prior as the band's sole remaining founding member. Although the band