How Tall Ships Sail
A tall ship sails because the wind blows her along. The wind will blow anything that floats freely before it, but a tall ship can sail almost against the wind. Why she can do this is due to two things - the pressure of the wind on the sails and the resistance that the water gives to the tall ship as the hull moves through the water. The wind pushing on the sails pushes the hull against the water, and the tall ship is forced ahead, or squeezed through the water.
But no tall ship can sail directly into the wind. If the tall sailing ship points the bow directly into the wind, it blows straight onto the sails and they flap. The tall ship has to turn away at an angle of about fourty five degrees and the wind blows on the sides of the sails and blows her along. A tall ship can ship almost anywhere with the wind except for forty five degrees either side of dead onto the wind.
A tall ship can get to the direction of where the wind is blowing from by making a zig zag course sailing as close as she can to the wind in one direction and then changing tack to have the wind blowing on the other side of the sails. Eventually by tacking continually a tall ship can sail in the general direction that the wind is blowing from.