
The question posed in the title, still have not found a final resolution. The first experiments to replace the traditional sail is a vertical wing, by profiling and design friends of the aircraft, did not bring the expected result. The fact that hundreds of years of its existence, the sail turned into a beautiful multi-device for conversion of wind power into thrust, informing the movement of the ship or the Buer. And it works quite effectively, and acute course, with strong and weak wind, his smooth flow and in the squalls. In addition, the sail is a great tool that allows the helmsman to accurately adjust it in accordance with the selected rate and direction of the wind, its force arising from the roll of a sailboat and other motion parameters.