The invention relates to an at least partially wind-propelled ship, comprising a double airfoil mounted on a structure controlled angularly around a generally vertical axis, where the double airfoil comprises a fore flap and an aft flap separated by a slit. At least one of the fore flap and the aft flap has a fore-to-aft asymmetry, wherein each flap comprises a series of shape members distributed in height. The structure comprises a fore mast and an aft mast connected by a boom member and by a gaff member. The shape members of the fore flap are traversed by the fore mast while being able to turn around an axis defined thereby, while the shape members of the aft flap are traversed by the aft mast while being able to turn around an axis defined thereby.