A wind-propelled vehicle, includes: a vertical mast assembly having a lower end rotatably mounted about a vertical axis on the vehicle; and a wing sail carried by the vertical mast assembly for propelling the vehicle, including a fore sail panel defining the leading edge of the wing-sail, and a pair of aft sail panels attached to a pair of booms defining the sides and trailing edge of the wing-sail. The vertical mast assembly includes a pair of vertically-extending posts connected together at their upper ends, diverging apart at their lower ends, and connected together at the diverging lower ends to define an “A” configuration frame. The diverging lower ends of the pair of posts are rotatably mounted on the vehicle.