Wingsail structure for a wind-assisted propulsion arrangement of a marine vessel

A wingsail structure for a wind-assisted propulsion arrangement of a marine vessel, the wingsail structure comprising:

• a wingsail frame comprising:
• a rigid or semi-rigid main wingsail having an aerofoil shape with a leading edge, a trailing edge, a top end and a bottom end, and side walls extending, therebetween;
• a rigid or semi-rigid flap having an aerofoil shape with a leading edge, a trailing edge, a top end and a bottom end, and side walls extending, therebetween;
• and
• at least one upper coupling member and at least one lower coupling member connecting the main wingsail and the flap;
• and
• a foundation arranged to be fixed to a body of the vessel, the foundation being associated with the wingsail frame such that the wingsail frame is rotatable in respect to the foundation via a first vertical axis of rotation,
• wherein the upper and lower coupling members are configured to:
• bring the main wingsail and the flap to a first unfolded standing position;
• and
• bring the main wingsail and the flap towards one another to a second folded standing position, and
• wherein the wingsail structure further comprises a tilting arrangement configured to bring the wingsail frame from the second folded standing position to a third tilted position in respect to the foundation.