A rig with a single sail shaped like a jib, the luff of which is attached, by a groove, to a round, revolving mast, though sometimes it is a double sail which can be set on either side of the mast when running free. The sail is reefed by spinning the mast with an endless rope, about ten turns rolling it up completely onto the mast. Ball bearings reduce the friction where the mast, which is stepped on the keel, passes through the deck. The halyard runs inside the mast and, for all practicable purposes, it is an unstayed rig, as there is no standing rigging apart from an adjustable backstay.
Subjects: Maritime History.