| 摘要 |
<p>The sailing rig for a small boat or sailboard consists of a triangular sail (10) which is attached to the mast (13) by a sheath (11) which encloses the mast. The sheath is made from a strip of suitable material which is folded around the mast and the two edges sewn to each other and to the edge of the sail. When the sail is under tension, the cross-section of the sheath has the appearance of an aerofoil with a rounded nose and triangular tail. This space of triangular cross-section between the mast and edge of the sail is filled with a cellular plastics which keeps the mast buoyant if the boat keels over and helps to restore it to the vertical position. If the rig has a horizontal boom or wishbone the sheath is made in two sections.</p> |
