Camber: Curvature of either sail or keel; the curve of the deck, usually being higher in the center so that the water can run off.

Can: A cylindrical buoy, generally green.

Canvas: Firm, closely woven cloth used for sails and awnings; a set of sails; today the word "sailcloth" is generally used for modern sailmaking fabrics such as polyester {Dacron} and nylon.

Capsize: To turn over; to turn bottom side up.

Capstan : A vertical winch on deck, used for hauling, such as the anchor line.

Carbon Fiber: Modern fiber used with epoxies in order to stiffen a component.

Cardinal Points: The four principal compass points; North, East, South, West.

Carlins: Fore and aft members of the deck frame; they support the coamings of the cockpit, the cabin trunk sides and the hatch coamings.

Carrick Bend: A useful knot for fastening two lines together; a number of variations exist.

Carry Away: To break loose, said of gear that is stressed beyond the strength of its fastenings.

Carvel: Smooth skin planking.

Cast Off: To loose, unfasten; to undo all mooring lines in preparation for departure.

Catalyst: Chemical used to activate polyester resins and other polymers.

Catamaran: A twin-hulled vessel, sail or power.

Catboat: A simple rig for a sailboat, with one mast and one sail, which may be either Marconi or with a gaff.

Catenary: In a rope or chain run between two points, the sag from a straight line due to the effect of gravity.

Cavitate, Cavitation: Turbulence in the water caused by rotation of a propeller; causes wear on the propeller and a reduction in propeller efficiency.

Ceiling: The inside lining of the hull.

Celestial Navigation: Position determination [and the total process of navigation based on it] by reference to sun, stars and moon. Usually a sextant measures the altitude of the observed heavenly body, a highly accurate source of time information is used to determine the time of the sight, and tables and/ or a navigational electronic calculator are used to determine a position line; the place where two lines cross is a fix.

Centerboard: A board or metal plate, moving vertically or pivoting up and down in a slot in the keel, which adds lateral resistance to the hull form of a sailboat; in effect the boat's sideways motion through the water is thus controlled by increasing the area of the keel.

Certificate: A government paper, such as a boat's license, or a seaman's or master's license allowing the operation of a commercial vessel.

Chafe: Abrasion, wear.

Chafing Gear: Cloth, tape or other material fastened around a line or other rigging to prevent wear.

Chain: Interlocking steel or iron links, used for anchor rodes and, on larger vessels, certain rigging parts.

Chain Locker: Stowage space for anchor chain.

Chainplates: Fittings on the sides of the hull or the outer edges of the deck of a sailboat, to which the port and starboard rigging, called shrouds, are fastened.

Chandlery: Items of nautical gear or the shop where these are sold.

Channel: The navigable portion of a waterway; the marked and designated area where there is a known depth of water; boats may not normally anchor in a channel.

Charlie Noble: A stovepipe fitting in a cabin top or deck, through which the metal "chimney" of a boat's cooking or heating stove passes; usually equiped with a cooling rim of water and a partial cap, to exclude rain and control smoke.

Charts : Seagoing maps; most charts are issued by governmental sources, and their data is based on surveys of the land and underwater areas, showing depths as well as buoys and other aids to navigation; they are updated periodically.

Chart Table: Also called navigation table, where charts are handled for the purpose of navigating.

Chine: The intersection between the topsides and bottom.

Chock: A rigging fitting, essentially shaped like a U or an O, normally mounted on deck or in the toe rail, to control a rigging or mooring line.

Chockablock: Full up, tight, drawn up as far as possible, as when two blocks in a tackle are closed up and no more movement of the line is possible.

Chop: Short, steep waves.

Clamp: The inner longitudinal timber or plank in the construction of a wooden vessel that acts as the bearer for beams or joints.

Classes: Organized groups of boats {essentially for racing}, with either identical measurements and specifications, or variable measurements to fit a formula, designed to equalize boat performance to some degree and thus put a premium on skill and tactics.

Cleat: A rigging fitting to which mooring lines, sail control lines such as sheets and halyards, and miscellaneous lines are temporarily attached.

Cleat Hitch: The distinctive crisscross or figure eight hitch used to fasten a line to cleat. (Belay)

Clevis Pin: A large pin that secures one fitting to another.

Clew: The lower, after corner of a sail, to which the sheet is attached.

Close Hauled: Hard on the wind, a point of sailing in which the sheets are hauled tight, enabling the boat to sail "against the wind."