Sunset Boats In The Rain Stock Photo

The physics of sailing arises from a balance of forces between the wind powering the sailing craft as it passes over its sails and the resistance by the sailing craft against being blown off course, which is provided in the water by the keel, rudder, underwater foils and other elements of the underbody of a sailboat, on ice by the runners of an ice boat, or on land by the wheels of a sail-powered land vehicle. Forces on sails depend on wind speed and direction and the speed and direction of the craft. The direction that the craft is traveling with respect to the `true wind` the wind direction and speed over the surface is called the point of sail. The speed of the craft at a given point of sail contributes to the `apparent wind`—the wind speed and direction as measured on the moving craft.