PURPOSE: To go by sail in any aimed course independently of wind directions by rotating a cylindrical sail which uses a mast as a revolving shaft and has a hemispheric head under wind speeds and rotating roary wings on both sides of a boat in conjunction with the revolution of the mast to advance a sailboat.

CONSTITUTION: A dangling radial cubic face with a hemispheric side of each wind acceptance sack 2 of a sail which uses a mast 1 as a revolving shaft is unfolded in a spherical arc radial fan shape under winds and is also unfolded in a dangling radial cubic shape with a hemispheric side, and a vertical revolution unit with the mast 1 acting as a central shaft is revolved in a constant direction under a rapid turning force irrespecrive of wind directions. A driving gear 7 is rotated in concurrence with the mast 1 of the vertical revolution unit, and drives rotary wings 12 to rotate rapidly through a driven gear 14 and a rotary shaft 13 to advance a boat 15. Wind speeds which unfold each wind acceptance sack 2 radially and rotate it vertically also go up while rotating a dangling radial cubic face with a hemisperic side of each wind acceptance sack 2, and givc strong wind pressures into an upper spherial arc radially unfolded fan-shaped sack, generating a floating lift by vertical revolution of the mast 1 as the central revolving shaft.