The present invention relates broadly to a rigid wing (10) which in its preferred embodiment is a rigid wing sail fitted to a water-borne vessel. The rigid wing sail (10) comprises a pair of elongate rigid panels (12A) and (12B), and a hinge element designated generally as (14) coupled to the panels (12/B) to permit pivotal movement of the panels (12A/B) relative to one another. Each of the pair of panels such as (12A) includes an adjoining edge (16A) and an opposing lateral edge (18A). The hinge element (14) is coupled to the panels (12A/B) at the respective adjoining edges (16A/B) to form either: 1) a closed configuration of the wing (10) with lateral edges (18A/B) of respective panels (12A/B) positioned adjacent one another wherein the rigid wing sail (10) is closed; or 2) an open configuration of the wing (10) with the lateral edges (18A/B) of the respective panels (12A/B) separated from one another wherein the rigid wing sail (10) is set at a variable camber.