Abstract: A rigid marine sail comprises a vertical mast secured onto a deck of a ship; at least one pivot shaft provided substantially in parallel with the mast; a left sail portion and a right sail portion pivotally secured respectively to the left side and the right side of the mast in parallel therewith through the at least one pivot shaft; and at least one drive mechanism for symmetrically pivoting the left sail portion and the right sail portion relative to the mast around the pivot shaft between a deployed position and a folded position.

Abstract: A rigid marine sail has a rigid left sail portion and a rigid right sail portion, both of which are pivotally secured to a mast on a ship so as to be pivotable about one common pivot axis which extends substantially parallel to the mast of the ship. The common pivot axis is spaced ahead of the mast with respect to the direction of intended movement of the ship. The left and right sail portions are foldable to an operable position by pivoting them about the common pivot axis and are also foldable to a streamlined folded inoperable position by being pivoted about the one common pivot axis, the left and right sail portions being substantially parallel to each other and closely facing each other when they are in their streamlined folded inoperable positions. A shroud is provided ahead of the common pivot axis with respect to the direction of movement of the ship. When the left and right sail portions are in their folded inoperable position, the shroud spans a gap between them to reduce air resistance.