_Chock-a-block._ When the lower block of a tackle is run close up to the upper one, so that you can hoist no higher. This is also called hoisting up _two-blocks_. CISTERN. An apartment in the hold of a vessel, having a pipe leading out through the side, with a cock, by which water may be let into her. CLAMPS. Thick planks on the inside of vessels, to support the ends of beams. Also, crooked plates of iron fore-locked upon the trunnions of cannon. Any plate of iron made to turn, open, and shut so as to confine a spar or boom, as, a studdingsail boom, or a boat's mast. CLASP-HOOK. (See CLOVE-HOOK.) CLEAT. A piece of wood used in different parts of a vessel to belay ropes to. CLEW. The lower corner of square sails, and the after corner of a fore-and-aft sail. _To clew up_, is to haul up the clew of a sail. CLEW-GARNET. A rope that hauls up the clew of a foresail or mainsail in a square-rigged vessel. CLEWLINE. A rope that hauls up the clew of a square sail. The clew-garnet is the clewline of a course. CLINCH. A half-hitch, stopped to its own part. CLOSE-HAULED. Applied to a vessel which is sailing with her yards braced up so as to get as much as possible to windward. The same as _on a taut bowline_, _full and by_, _on the wind_, &c. CLOVE-HITCH. Two half-hitches round a spar or other rope. (See PLATE 5 and page 48.) CLOVE-HOOK. An iron clasp, in two parts, moving upon the same pivot, and overlapping one another. Used for bending chain sheets to the clews of sails. CLUB-HAUL. To bring a vessel's head round on the other tack, by letting go the lee anchor and cutting or slipping the cable. (See page 76.) CLUBBING. Drifting down a current with an anchor out. (See page 77.) COAKING. Uniting pieces of spar by means of tabular projections, formed by cutting away the solid of one piece into a hollow, so as to make a projection in the other, in such a manner that they may correctly fit, the butts preventing the pieces from drawing asunder. _Coaks_ are fitted into the beams and knees of vessels to prevent their drawing. COAL TAR. Tar made from bituminous coal. COAMINGS. Raised work round the hatches, to prevent water going down into the hold. COAT. _Mast-Coat_ is a piece of canvass, tarred or painted, placed round a mast or bowsprit, where it enters the deck. COCK-BILL. To cock-bill a yard or anchor. (See A-COCK-BILL.) COCK-PIT. An apartment in a vessel of war, used by the surgeon during an action. CODLINE. An eighteen thread line. COXSWAIN. (Pronounced _cox'n_.) The person who steers a boat and has charge of her. COIL. To lay a rope up in a ring, with one turn or fake over another. _A coil_ is a quantity of rope laid up in that manner. COLLAR. An eye in the end or bight of a shroud or stay, to go over the mast-head. COME. _Come home_, said of an anchor when it is broken from the ground and drags. _To come up_ a rope or tackle, is to slack it off. COMPANION. A wooden covering over the staircase to a cabin.