Is a sailing boat is powered by the wind?

Most of the time. Some are powered by motors, but all of them have the sails (different numbers for different kinds of ships). The wind catches in the sails and moves the boat. Depending on the angle of the sail, the ship can move in almost any direction. Though it is easiest when the wind is right behind the boat. When the wind is blowing in the opposite direction you want to go, then there is a technique that you can use called "tacking".