Cast off. To untie; to free.
Casting. To pay a vessel off on the desired tack.
Cat’s paw. A light puff or current of wind seen on the surface of the water. A kind of knot or bend.
Chock a block. See Block and Block. Also used to denote fully laden.
Cleat. A metal or wooden object to which ropes are fastened.
Clew. The after corner of a fore-and-aft sail. The two lower corners of a square sail.
Close hauled. Sailing as nearly as possible into the wind.
Cockpit. The open after part of a boat.
Course. The direction in which a boat is to proceed. The lower sails on square-rigged vessels.
Crank or cranky. Not stable. Unable to carry sail well. To tip easily. Unsteady.