Can a sailboat go upwind?

The most important driving force for a sailboat traveling against the wind is suction.

According to aerodynamics, as fluid speed increases, pressure decreases. Air to go around the outward curved sail surface, must speed up, so the pressure decreases, resulting in suction, pulling the sail to one side. The suction on the leeward side of the sail due to the reduced pressure is quite large, and can be twice as strong as the force pushing the sail on the windward side.

The wind on both sides of the sail generated by the suction and thrust, so that the boat side to side; but the centerboard to prevent the boat side to side, so the wind breaks down into two forces, a force to push the sailboat forward, the other force will make the boat to the leeward side of the side of the tilt to the other side of the boat to the sail helmsman in the other side of the boat to explore the outside, to maintain the balance.

A sailboat cannot sail completely head to wind. A 12-meter-long sailboat can be 12-15 degrees with the wind direction of the angle upwind. If you want to face the direction of the wind, you must sail in a "zigzag" route. When sailing upwind, the smaller the angle between the boat and the wind, the slower the speed. If the helmsman sails a zigzag course with a larger angle, the boat will go faster, but the voyage will be longer.