The force of the wind is used to create motion by using one or more sails. The movement of air over the sails acts in the same way as air moving over an aircraft's wing. Just like on an airplane, air flowing over the sail is deflected and accelerated. This generates lift, which acts to pull the sail, and thus the boat ahead, but also slightly downwind. The downwind component is offset by an underwater hydrofoil whose shape resists lateral movement while offering little resistance to forward motion. Without this hydrofoil sailing upwind or across the wind would be virtually impossible. Sailing hydrofoils include keels, centerboards, daggerboards, and less commonly leeboards.
The lifting force of the sails also acts to lean the boat over to one side, which is called heeling. In monohull vessels, heeling is counteracted by ballast, either in the form of dense material located deep in the bilge or externally in the keel (usually lead or iron) or in the form of human or water ballast located near the windward rail. In multihull vessels (catamaran or trimaran) righting force may also be created by the counteracting buoyancy of the leeward hull. Too much heeling may lead to a capsize.
Today, for most people, sailing is a hobby. Pleasure sailing can be further divided into Racing, Cruising and Daysailing.
In ancient times (see Odysseus), ships used following or rear-quarter winds. Therefore, they had to wait in port or at sea for the right wind directions.

haha. just being lame. ((:
+val+