Sail propulsion element, sail-propelled vehicle

A sail propulsion element comprising:

• a mast (3);
• an inflatable sail (1) consisting essentially of two substantially fluidtight adjacent surfaces (4a, 4b) joined together along a periphery of the surfaces, forming between them at least one cavity closed around the mast (3), the inflatable sail comprising an upper part, a lower part, a leading edge (6) and a trailing edge (7);
• at least one air conduit positioned between an inside and an outside of the at least one cavity of the inflatable sail;
• at least one means for injecting air into the at least one cavity, the inflatable sail once inflated having a profile that remains permanently symmetrical, irrespective of movement of the sail propulsion element, or of a direction or strength of wind;
• a headboard positioned on the upper part of the inflatable sail;
• and
• a sail receptacle positioned between the leading edge (6) and the trailing edge (7) on the lower part of the inflatable sail,
• wherein the inflatable sail comprises a plurality of cells (5) in a direction of a span of the inflatable sail, each cell (5) extending from the leading edge (6) to the trailing edge (7), the plurality of cells (5) being spaced apart by ribs (8) made of a first soft material that allows air to pass.