Cable—A rope or chain used to anchor a boat.
Capsize—To upset.
Cast off—To loosen, as cast off that line.
Casting—To pay a boat’s head off from a mooring by getting the sails aback or by using a spring line.
Cat rig—A vessel with one mast, placed right in the bow, and carrying a single sail.
Centerboard—A keel that can be lifted up and down. It is hung in a trunk or box which is built up inside the boat to keep the water out.
Cleat—A piece of wood, iron or brass used to fasten or belay ropes to.
Clews—The corners of a sail.
Close-hauled—A vessel is close-hauled when she is sailing as close to the wind as possible.
Coil—To gather a rope into a series of circles so that it will roll out again without getting tangled.