Abstract: A sail for the propulsion of elements of transport, which comprises a sheet-like body made of flexible material which is connected, along one of its edges, to a supporting mast, connected to an element of transport. At least one stiffening rib is associated with the sheet-like body and is accommodated in a respective pocket which is formed in the sheet-like body and extends for at least one portion of the sheet-like body comprised between the supporting mast and the edge of the sheet-like body that is opposite to the one connected to the supporting mast; the rib has, or can assume on command, a substantially arc-like shape adapted to generate lift. Elements are further provided for varying the orientation of a concave part of the rib with respect to the supporting mast.

Abstract: A sail for the propulsion of elements of transport, which comprises a sheet-like body made of flexible material which is connected, along one of its edges, to a supporting mast, connected to an element of transport. At least one stiffening rib is associated with the sheet-like body and is accommodated in a respective pocket which is formed in the sheet-like body and extends for at least one portion of the sheet-like body comprised between the supporting mast and the edge of the sheet-like body that is opposite to the one connected to the supporting mast; the rib has, or can assume on command, a substantially arc-like shape adapted to generate lift. Elements are further provided for varying the orientation of a concave part of the rib with respect to the supporting mast.