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C

Cabin. The interior of a deck house, usually the space set aside for the use of officers and passengers.

Cabinet, Metallic or Wood. A piece of furniture used for holding clothing and other objects. When made of metal it is generally finished off to resemble wood.

Cable. See Rope, Definitions.

Cable-Laid Rope. See Rope, Cable-Laid.

Cable Length. A rough measure of distance equal to about six hundred feet.

Cable Molding. A molding often used in decorating a vessel’s stern. It is carved to simulate the appearance of a rope.

Cables, Electric. See Electric Wires and Cables.

Caisson. A watertight structure used for raising sunken vessels by means of compressed air.

Caliber. A term applied to the inside diameter of a cylinder, tube or pipe.

Calipers. A gauge having two arms of equal length operating on a hinged joint, and used to measure and transfer dimensions, without the use of figures, on machine or wood work.

Calked Deck. See Deck, Calked.

Canal Horn. A horn, usually of brass and similar to those used on stage coaches, which was blown by men on narrow boats to warn lock-keepers and others of their approach, before the steam whistle was invented.

Caulkers. (Steel) Workmen who secure the water- and oil-tightness of joints in steel ships by swaging the metal into the openings between plates or other parts. This work is generally done with suitable tools driven by compressed air.

(Wood.) Workmen who open the seams between the planks and drive in oakum or cotton to make them watertight.

Calking. To make watertight by swaging the sight edges or shapes or plates riveted in place. In wood work to make watertight by filling the seams with oakum.

Calking Box. A caulker’s kit box.

Calking Iron. A tool used for driving oakum into seams.

Calking Hammer, Pneumatic. A light machine operated by compressed air, in which a calking tool with its shank having a sliding fit in the bore of the machine is given very rapid, short and powerful strokes.

Calking Mallet. A wooden mallet used for striking the calking tool when calking a wooden vessel.

Calking Pitch. See Glue, Marine.

Calorimeter. An instrument used to determine the moisture content of steam.

Cam. A surface made up of a series or combination of inclined planes to which rotary motion is imparted by means of the shaft on which carried. The cam action may take place either in a plane perpendicular to the shaft axis or in a plane parallel thereto. Cams are generally constructed of hard steel to insure good wearing qualities.

Cam Shaft. A shaft designed to carry and actuate cams.

Camber. Round of Beam. The weather decks of ships are rounded up or arched in an athwartship direction for the purpose of draining any water that may fall on them to the sides of the ship where it can be led overboard through scuppers. This arching or rounding up is called the camber or round of beam and is expressed in inches in connection with the greatest molded breadth of the ship in feet.

Camel. A float used for helping vessels over sand bars and the like. Tile process of usage is as follows: the camel is flooded and sunk alongside the vessel to be raised. In its sunken position it is secured to the vessel, after which the water is pumped from the camel, the supplying additional buoyancy which raises the vessel.

Candle-power. The practical unit of the luminous intensity of sources of light

Cant. A term in general use by shipwrights signifying an inclination of an object from a perpendicular; to turn anything so that it does not stand perpendicular or square to a given object.

Cant Beam. See Beam, Cant.

Cant Body. That portion of a vessel’s body either forward or aft in which the planes of the frames are not at right angles to the center line of the ship.

Cant Frames. See Frames, Cant.

Cant Hook. A lever fitted with a hook, used for turning or slewing heavy articles, especially timbers. The lower end of the lever is sometimes shod with pointed metal.

Canvas Covered Deck. See Deck, Canvas Covered.

Canvas Preservatives. See Paint.

Capacity. The measure of power to receive or contain or the measure of ability to exert .power. Illustrations: A hold of five hundred tons "capacity." A crane of ten tons "capacity."

Capacity, Boiler. See Boiler, Capacity.

Capping or Nosing. A term applied to a molding used in covering over the joints in joiner work.

Capstan. A device made of iron and wood for hauling up anchors and cables, taking down the foresail tack, aboard ship, or for drawing light boats above high watermark. The cable is wound round an upright cylinder revolving upon a pivot. At intervals in the upper part of the cylinder there are one or two rows of square holes, in which poles or bars are inserted to act as levers for the turning. The cable coils beneath these bars. The center-line capstan on the Victory had fourteen sockets around its upper part for the capstan bars. If ten men stood to a bar then 140 would be required to hoist a heavy item. The main capstan, used for weighing the anchors, would require 280 men. The decorated top of the center-line capstan was detachable, so that the ship’s fiddler or other musician could stand in its place and perform while the men heaved the bars.

Capstan Bar. A hard wood or steel bar used in turning a capstan by hand.

Capstan, Electric. A power driven capstan in which the electric motor replaces the seam engine. The motor may be connected directly or by means of reduction gearing to the capstan shaft.

Capstan Foundation. A term applied to a seating prepared for a capstan. This seating is usually constructed by reinforcing the deck with a thicker or extra plate with bars worked between the deck beams beneath.

Capstan, Steam. A vertical drum or barrel operated by a steam engine and used for handling heavy anchor chains, heavy hawsers, etc. The engine is usually non-reversing and transmits its power to the capstan shaft through a worm and worm wheel. The drum is fitted with pawls to prevent overhauling under the strain of the hawser or chain where the power is shut off. The engine may be disconnected and the capstan operated by hand through the medium of capstan bars.

Carbon Black. See Paint

Careen. To incline from the upright either by the elements or mechanically for the purpose of making repairs.

Cargo. Merchandise or goods accepted for transportation by ship.

Cargo, Deck. See Deck, Cargo.

Cargo Hatch. See Hatch, Cargo.

Cargo Hoist. See winch.

Cargo Hold Bulkhead. See Bulkhead, Cargo Hold..

Cargo Mat. A mat, usually square in form, used to protect the deck covering, locally, when taking stores, ammunition, etc., on board. In its construction, manila rope is generally used. The strands being unlade are hung over a jackstay on either side, carried around, tied, and tucked to conform to the contour of the mat. The surface then is thrummed to produce a cushioning effect.

Cargo Net. A square net made in various sizes of manila rope or chain and used in conjunction with the vessel’s hoisting appliances such as davits, boat cranes, etc., together with the necessary tackles, in hoisting stores, ammunition, etc., aboard ship. The outer edges of rope nets are formed by a continuous jackstay around the net with a bight or sling formed at each corner by seizing the two parts together. The meshes are made by crossing two sets of ropes at right angles to each other and to the jackstay, the ends stuck through the jackstay, a round turn taken and spliced into its own part. At the crossings one rope is pulled through the other under one strand and alternately hitched to right and left.

Cargo Port. See Port, Cargo.

Cargo Reflector. See Reflector, Cargo.

Carlines. A term applied to short fore and aft beams running under the deck beams or intercostal between them.

Carlines, Beam. See Beam Carlines.

Carlines, Hatch. See Hatch Carlines.

Carpenter (Ship). A woodworker who does the heavier and rougher wood work. In steel shipbuilding he sets the keel blocks and ribbands, builds stages, places the launching ways and packing.

Carrier, Rudder. See Rudder Carrier.

Carrying Dog. A tool with its end so shaped that it can be slipped over the edge of a plate or shape to facilitate its handling.

Casemate Armor. An armored bulkhead or belt fitted on a naval vessel. It may be pierced by gun ports. Ordinarily this armor is of less thickness than the main side belt and is fitted above the latter.

Casing, Boiler Room. The partition or walls enclosing the space above the boiler room in the way of the boiler hatch. This casing should form a trunk of sufficient size to allow the installation and removal of the boilers, and also, when the boilers are in position, to accommodate the smoke stack and ventilator cowls that leach to the boiler room. Doors are fitted in the casing at the deck levels thick give access to gratings and ladders leading into the boiler room. The top of the casing should project well above the weather deck where there is no superstructure and should be carried up through the superstructure where one is erected.

Casing, Deck Piping. Covering plates built over exposed deck piping for protection.

Casing, Engine Room. The partitions or walls enclosing the space above the engine room in the way of the engine room skylight and hatchway. The casing forms a trunk suitable for access, light and ventilation. At the top of the casing a skylight with hinged covers is fitted through which the heat from the engine room escapes. Doors are fitted in the casing at the deck levels which give access to gratings and ladders leading down into the engine room. Care should be taken that the engine room casing encloses a space sufficiently large to provide for installing the engines and for lifting the cylinder covers where reciprocating engines are used. Portable strong beams are fitted in the casing trunk to compensate for the opening and for convenience in lifting covers, etc. The top of the casing should project well above the weather deck where there is no superstructure and should be carried up through the superstructure where one is erected.

Casing, Turbine. See Turbine, Cylinder or Casing.

Cast Iron. Described under Steel and Iron.

Cast Steel Wire Rope. See Rope, Cast Steel Wire.

Casting Bow. See Stem.

Casting, Stern. See Stern Frame.

Castings. Metal frames, gears, housings, etc., made by pouring molten metal into forms and allowing to cool. Stems, stern frames, struts, stern tubes, bitts, chocks, turbine casings, cylinders, gear wheels, etc., are some of the castings common in ship work.

Castors, Plate. A plate castor is essentially a wheel mounted in such a manner on a post, about two feet high, that it is free to turn on its own axis or around the axis of the post. On a series or bed of such plate castors, ship plates in the course of construction can be easily rolled and handled by a small number of men during the shearing, punching and forming operations. Plates may be handled with these castors without the use of overhead cranes, thus materially reducing the labor required. The use of plate castors as a means of handling steel plates has been customary in large steel mills for the past twenty-five years, but they have only been recently applied to shipyard use. They are economical and if properly constructed are a material aid in reducing the labor necessary for manipulation of ship plates of all sizes.

Cat Davit. See Davit, Cat.

Cat Head. A term applied to a short beam or support projecting over the sides of a vessel at the bow for the purpose of taking the cat tackle

Cat Hook. A term applied to a hook used in picking up an anchor after it is brought to the surface.

Cat Tackle. A tackle used in raising an anchor from the surface of the water or from under the hawse pipe.

Cavil. A large piece of timber fastened to the forward or after bitts about midway between the base and top forming a cleat.

Cavitation. The breaking down of the continuous stream lines flowing through a propeller. Cavitation takes place at high speed due to the inability of the water to flow into the wheel as rapidly as it is forced astern.

Ceilers or Planers. Wood workers, carpenters who fit the planking on the inside and outside of the frames of a wooden vessel.

Ceiling. A term applied to the planking with which the inside of a vessel is sheathed. Also applied to the sheet metal or wood sheathing in quarters and storerooms.

Ceiling, Floor. Planking fitted on top of the floors or double bottom in the cargo holds.

Ceiling Hold. A term applied to thick strakes of planking fastened to the inside flanges or edges of the framing in the cargo holds.

Center Board. A heavy slab of wood or metal fitted in a vertical slot on the centerline of a sailing boat. It can be raised or lowered and when lowered it projects below the keel keeping the boat from slipping to leeward.

Center Line Bulkhead. See Bulkhead, Center Line.

Center of Buoyancy. The geometric center of gravity of the immersed volume of the displacement or of the displaced water. It is determined solely by the shape of the underwater body of the ship and has nothing to do with the center of gravity of the ship.

Center of Buoyancy, Longitudinal. The location longitudinally of the center of buoyancy is usually stated as a distance either forward or aft of the middle perpendicular.

Center of Buoyancy, Vertical. The distance in a vertical direction of the center of buoyancy measured from a given reference line, frequently the bottom of the vessel’s keel, though sometimes the plane of the designed waterline.

Center of Effort. Term generally used in connection with sails, meaning the center of the application of wind pressure against the sail area. Ordinarily no allowance is made for variation in wind pressure over the sail and the center of effort is assumed to be the center of gravity of the sail area.

Center of Floatation. That point about which a vessel rotates when slightly inclined in any direction from her free position of equilibrium by the action of an external force without change in her displacement. The center of floatation is coincident with the center of gravity of the water plane of the vessel in her initial condition.

Center of Gravity. The point at which the combined weight of all the individual items going to make up a vessel’s total weight may be considered as concentrated.

Center of Gravity, Longitudinal. The location of the center of gravity as regards its longitudinal position, usually stated as a distance either forward or aft of the midship frame or the middle perpendicular.

Center of Gravity, Vertical. The location of the center of gravity as regards its vertical position, usually stated as a distance above the base line or bottom of keel.

Center of Lateral Resistance. That point through which a single force could act producing an effect equal to the total lateral resistance of the vessel. The center of lateral resistance is ordinarily assumed to be coincident with the center of gravity of the central immersed longitudinal plane.

Center of Pressure. That point in a sail or an immersed plane surface at which the resultant of the combined pressure forces act. The center of pressure on a sail is the point at which the resultant of the wind pressure acts and the center of pressure on a rudder is a point at which the resultant of the water pressure acts.

Centrifugal Pump. See Pump, Centrifugal.

Chafe. To destroy or wear away by rubbing or abrasive action.

Chafing Plate. A plate worked around the lower edges of hatch beams or carlines to prevent wear of the hoisting ropes. Also applied to plates fitted on the forecastle deck under the anchor chains.

Chain. See Equipment.

Chain, Close Link. Sometimes known as short link chain. Chain in which the links are so short relative to their width that studs cannot be fitted.

Chain Compressor. A forging fitted below the upper deck and pinned at one end to the deck casting at the head of the chain pipe or to the ship’s structure near by. At the other end of the shank an eye is worked for the attachment of a tackle. The controller is so located that the application of force by tackle or other means at the eye controls or stops entirely the passage of the chain by forcing it against the chain pipe.

Chain Controller. A device located on deck between the windlass and the hawse pipe in line with the anchor chain. The compressor consists of a heavy cast or forged bed shaped to receive a link of the anchor chain and a lever so arranged as to force the chain into the bed at the will of the operator. This device is termed a chain compressor in the merchant service.

Chain Hoist. A deferential block and chain fall operated by an endless chain. Chain hoists are used for raising heavy weights about a shop and weights like cylinder heads, auxiliaries, etc., aboard ship.

Chain Lockers. Spaces or compartments intended for stowage of the anchor chains. They are usually located in the fore hold directly underneath the windlass with chain pipes connecting them to the anchor deck under the wildcats.

Chain Pipe. A pipe generally of cast iron, though sometimes of wrought iron or mild steel, leading from the upper deck bolster to the chain locker for the purpose of handling the anchor chain. At its lower end it is fitted with a half round or so shaped as to prevent the chafe of the chain when running out. Chain pipes are usually set at an angle to the vertical in order to minimize the noise made by the chain swinging against the chain pipe with the vessel’s roll.

Chain, Stud Link. Chain in which each link has a short distance piece (known as a stud) worked at its mid-length at right angles with its major axis. This is done in order to maintain the link shape.

Chain Stopper. A device used to secure the chain cable when riding at anchor, thereby relieving the strain on the windlass and for securing an anchor in the housing position in the hawse pipe. Stoppers differ widely in construction. For the smaller cables they are of rope, usually hemp, with a stopper knot or an iron toggle in the outer end and a lanyard for lashing to the cable. For larger cables wire rope is used in lieu of hemp, while for the largest cables the stoppers are of heavy chain fitted with slip hooks and turnbuckles for adjusting and for equalizing the strain when more than one stopper is attached to a cable. According to its use a chain stopper is termed a "riding stopper" or a "housing stopper". The inner end of the stopper is attached to a deck pad by means of a shackle or lashing.

Chain Tierers. The men who stow the chain cables as they are paid down into the chain locker. The chains are arranged regularly in symmetrical long flakes in a fore and aft direction. The tierers use chain-hooks and hook-ropes and in some cases tackles in performing their work. Some cables are too heavy to be handled by tierers and are stowed in deep and narrow lockers, where the chain is allowed to assume any position as it is paid down.

Chamfer. To bevel.

Channel Bar. A rolled shape, generally of mild steel, having a cross section shaped like that of an I-beam from which both flanges on the same side of the web have been cut even with that face of the web. In ship work it is used for frames, deck beams, bulkhead stiffeners,etc. The size denoted by dimensions of cross-section and weight per running foot.

Channel Bar, or Channel Frame. See Frame, Channel Bar.

Charlie Noble. The hood of the galley smoke pipe, sometimes used to mean the entire smoke pipe including the hood.

Chart. In general, a map showing the contour of coasts, the location of shoals, rocks, soundings, etc. There are many charts which do not fall strictly within the above definition, such as Charts of the inclination, Great circle charts, Heliographic charts, Physical charts, Selenographic charts, Variation charts etc. The earliest surviving sea map charts date from about 1300, but certainly had predecessors long before that. Early examples were called a periplus or coast pilot, mainly a description of a sailing route with instructions. There are references to an example from 450 B.C., which concerns a voyage to Gibraltar and along the west coast of Africa. Many early charts are undated, and can be judged for age only by their style.

Chart House. A house on or near the bridge, provided with stowage for navigation charts and facilities for their use.

Chasers. A term sometimes applied to assistants to the yard or shop superintendent. Their functions are to see that the work is promptly started, that the proper sequence of the steps involved is taken, and that the work is not interrupted. Also called Runners.

Check Line. An auxiliary line used only for checking dimensions.

Check Pin. A pin designed for securing the crank pin against turning. It is usually of steel and fitted into the crank web.

Check Ring. A protective ring. Usually fitted to prevent the working loose of another part.

Check Valve. See Valve, Check.

Checks. A term applied to cracks or openings in the grain of wood caused by shrinkage of the material in the process of drying. The checks are not continuous and vary in depth from about one sixteenth of an inch to the entire thickness of the wood.

Cheek Block. See Blocks, Cheek.

Cheeks of a Block. The outer sides of the frame.

Chine. The line formed by the intersection of side and bottom in ships having straight or slightly curved frames.

Chining. The inserting of oakum or cotton between plank edges of boats.

Chipper. A workman who cuts or trims away the edges of plates, shapes, castings or forgings, either by hand or by pneumatic tools. Chipping may be necessary in order to secure a good calking edge or for fitting or finishing purposes.

Chipping Hammer, Pneumatic. A light machine operated by compressed air, in which a chipping tool with its shank having a sliding fit in the bore of the machine is given very rapid, short and powerful strokes.

Chock. A term applied to oval shaped castings, either open or closed on top, and fitted with or without rollers, through which hawsers and lines are passed. Also applied to blocks of wood used as connecting or reinforcing pieces, to blocks of wood used as filling pieces, and to supports for life boats.

Chock, Boiler. See Boiler, Chock.

Chock, Boom. A block of wood shaped to receive a boom and used as a rest when the boom is stowed and not in us.

Chock, Bow. A wedge shaped piece of timber used as an abutment for the bowsprit.

Chock, Closed. A term applied to oval shaped castings, through which hawsers or lines are passed, having no opening in the top.

Chock, Open. A term applied to an oval shaped casting used for passing hawsers or lines through and having the top open.

Chock, Roller. A term applied to an oval shaped casting fitted with one or more rollers and used for the purpose of passing hawsers and lines through.

Chock, Rolling. See Keel, Bilge.

Chocks, Filling. Timber filling in the triangular space between the bobstay piece, the gammoning piece and the stem.

Chronometer, Marine. A timepiece mounted on gymbals in a glass-covered case to keep it horizontal and to preserve it from vibration, dust, drafts, and fluxuations of temperature. The mechanism is of a superior construction, having adjustments and compensations for temperature. While generally designed to run 56 hours, it is wound daily at a stated hour and is not regulated. The instrument is set as accurately as possible and its accuracy observed in an observatory. A certificate of rating is issued, showing its rate of gain or loss and this cumulative error must be considered when observing the time.

Circuit Breaker. An electric switch equipped with a carbon break and a trip for opening.

Circuit Breaker, Automatic. A circuit breaker, designed for automatically opening an electric circuit when a predetermined abnormal condition exists in the circuit in which the circuit breaker is connected.

Circuit Breaker, Automatic Resoling. A circuit breaker which will automatically open the circuit in which it is connected when a predetermined abnormal condition exists in that circuit and which will close the circuit automatically when the condition ceases to exist.

Circulating Pump, Auxiliary. See Pump, Auxiliary.

Circulating Pump, Distiller. See Pump, Distiller Circulating.

Circulating Pump, Main. See Pump, Main Circulating.

Circulating and Air Pump. See Pump, Air and Circulating.

Circulation, Boiler. See Boiler Circulation.

Circumferentor. An instrument, probably invented by Gemma Frisius (1508-1555), an instrument-designer of Louvain, which was used on survey ships and by surveyors to measure vertical and horizontal angles, and to chart coastlines in the 17th and 18th centuries. It is essentially a surveyor’s compass, and was introduced into England by John Norden (1548-1625), an English surveyor. Eventually it was superseded by the theodolite. It should not be confused with the earlier Holland Circle. It comprises a compass with magnetic needle, around which is a graduated, non-magnetic brass ring or circle, divided into 360 degrees, mounted on a horizontal brass bar, on which two sight rules or alidades are positioned vertically to the outer ring. There are two slots parallel and longitudinal to the strip’s edge. Some had a fine wire through the center of the sights. The needle would be positioned at north, using the compass, and the sight rules would be fixed on two predetermined points, so that their azimuths could be noted and the survey related properly to cadastral maps, which are maps of territorial property. When mounted horizontally on a stand, the circumferentor was used to measure horizontal angles, and when shackle-suspended it could measure vertical angles.

Clack. A simple form of check consisting of a flap suspended vertically or nearly vertically from hinges at top. Purpose: to limit flow of liquids to one direction only.

Clack Box. The casing enclosing the clack, The whole forming a clack valve. Box usually a casting Similar to other valves.

Clack Door. Cover providing access to interior of clack box.

Clamp. A device for holding two or more pieces of material together. It is generally operated by hand.

Clamp. A metal fitting used to grip and hold wire ropes. Two or more may be used to connect two ropes in lieu of a short splice or in turning in an eye.

Clamp, Deck Beam. A wood ship term applied to the fore and aft timber fastened to the frames and reinforcing the shelves which support the deck beams.

Clamp, Rudder. A term applied to the timbers that are fitted on both sides of the rudder and after portion of the stern to keep the rudder in a fore and aft position during the launching.

Clapper. See Tumbler.

Clasp Hook. Two hooks or one hook in two parts each forming a mousing for the other, and suspended from the same link or eye; or a pair of hooks whose jaws overlap and are held in place by a sliding ring. Also known as clip hook, See Sister Hooks.

Classification. Certification by a classification society as to the character of construction and outfitting of the vessel classed.

Classification Society. An institution that supervises the construction of vessels throughout under established rules, tests all materials for hulls, machinery and boilers; proof tests all anchors and anchor chains and issues Certificates of Classification which are a builder’s receipt, and owner’s guarantee, an underwriter’s authority and a shipper’s business guide.

Claw Off, Claw. To work a vessel off a lee shore to windward; especially when the performance is attended with great difficulty.

Clearance. The distance between the face of the piston, at the end of the stroke, and the inner face of the cylinder head, also the volume between the face of the valve and the face of the piston, the latter being at the end of the stroke, plus the volume of the steam port to the valve seat. It is frequently expressed as the percentage which the above volume makes of the volume swept by the piston. Clearance is allowed in order to avoid the possibility of knocking the head off in case of the accumulation of water in the cylinder. The clearance volume must be filled with steam at each stroke before the piston can be moved. This steam is not effective for work before expansion begins. A great portion of the loss due to this cause may be made up by cushioning the piston which consists of compressing the exhaust steam before the end of the stroke is reached. Cushioning assists in gradually stopping the piston, in restoring the temperature of the sides of the cylinder, which tend to cool during exhaust, and in producing uniformity in the tangential effort on the crank pins especially in high speed engines.

Clear Hawse. A vessel is said to have a "clear hawse" if when moored her cables lead off to the anchors on their respective sides clear of each other, i. e., without a cross in the hawse.

Clear Hawse Pendant. A strong pendant used in clearing hawse, consisting, usually, of a wire rope tailed with about six fathoms of chain and fitted with a pelican hook for connecting to the chain cable.

Clearing Port. See Port, Bulwark, Clearing of Freeing.

Cleat, or Cavil. A wood or a metal fitting having two projecting arms or horns to which a sheet, halyard or other rope is belayed. The deck, side plating, a stanchion, or other convenient structure serves as a support for securing the cleat. The term cavil is sometimes applied to a cleat of extra size and strength.

Clew. Either lower corner of a square and the lower after corner of a fore and aft sail; the nettles of light line woven into a sword mat at each end of a hammock by which it is suspended; the ring, heart, spectacle, or other shaped iron worked into the corner of a sail; to haul, by means of the clew garnets and crew lines, a sail up to the yard for furling; also to force a yard down by hauling on the clew lines.

Clinch. The end of a rope half-hitched around the standing part and stopped; to spread or rivet the point of a pin or bolt upon a plate or ring to prevent it from pulling out.

Clinch Ring. An oval shaped, heavy ring similar to a washer used under the heads of bolt and spikes where they pass through wood.

Clinching Plate. A small piece of plate used in the mold loft for backing up the nails or tacks used to hold a wood template together. After nailing the pieces of a template together it is turned over and the connections placed over the plate, while clinching the points of the tacks.

Clinker Built. See Plating, Clinker System.

Clipper Bow. See Bow, Clipper.

Clips. Short lengths of bars, generally angles, used to attach and connect the various members of the ship structure.

Club Foot. A fore foot in which displacement or volume is placed near the keel and close to the forward perpendicular. Its use results in forward sections with a marked tumble home at and below the load water line. It results further in very full forward endings for the lower water lines and a relatively fine entrance for the load water lines. A club foot may he used with advantage in vessels designed for speed length ratios below 1.1 particularly where such vessels have good draft.

Clump Block. See Block, Clump.

Clutch. A device designed to permit connecting and disconnecting two adjacent lengths of shafting in as expeditious a manner as possible. Clutches may be of various types depending upon the method of operation employed. Some of the principal types are as follows: mechanical, frictional, pressure and magnetic.

Coal Bunker. See Bunker, Coal.

Coal Bunker Bulkhead. See Bulkhead, Coal Bunker.

Coal Bunkers. The spaces allotted for stowage of coal for ships’ use.

Coal Forge. A forge in which coal is used as fuel.

Coal Passer. A member of a ship’s boiler room force who removes the coal from the bunkers and supplies it to the firemen or stokers.

Coaling Hatch. See Hatch, Coaling.

Coaling Port. See Port, Coaling.

Coaming, Bulkhead. A term applied to a strake of plating running across the top and bottom of tween deck, poop, bridge and forecastle bulkheads. The coamings are usually made thicker than the remaining plating and serve the function of top and bottom supports.

Coaming, Hatch. A frame bounding a hatch for the purpose of steering the edges of the opening and forming the support for the covers. In a steel ship it generally consists of a strake of strong vertical plating completely bounding the edges of a deck opening. In wood ships this coaming consists of heavy timber forming a frame around a hatch.

Coaming, House. A term applied to the narrow vertical plates bounding the top and bottom of a deck house. These plates are made somewhat thicker than the side plating and form a frame for the base and top of the house. Also applied to the heavy timber forming the foundation of a wood deck house.

Coaming, Man Hole. A frame worked around a man hole for the purpose of stiffening the edges of the opening and providing a support for the cover.

Coaming, Skylight. See Skylight, Coaming.

Cock. A valve which is opened or closed by giving a disc or tapered plug a quarter turn. When a plug is used it is slotted to correspond with the ports in the valve.

Cock, Air. A cock for the control of air entry or escape from pump, condenser, etc.

Cock, Ash. Cocks for supplying water to the fire room for use in cooling hot ashes, etc.

Cock, Drain. A small cock fitted to cylinders, steam jackets and other chambers so that any water which may collect can be drained away.

Cock, Feed. A cock for the control of the feed water flow.

Cock, Pet. A small cock used to test the working of bilge, feed and other similar pumps, and to indicate, in lieu of a gage-glass, the height of water or other liquid in a tank or other container. Also used for draining cylinders.

Cocked Hats. A form of headgear worn by naval officers, sometimes with gilt, braids, feathers, and escutcheons. They were worn athwart until about 1795, when officers of captain’s rank and below started to wear them fore and aft. In 1825 all officers were ordered to wear them fore and aft.

Cockpit. Originally this term applied to a compartment below the gun deck of men of war, devoted during battle to the surgeon and his assistants. Applied to small boats, it refers to a sunken place or pit for the accommodation of the crew.

Cocks, Test. Small cocks either attached to the boiler shell or to a separate mounting for the purpose of indicating the water level within the boiler. Test cocks are usually three of four in number. The lowest is usually located several inches above the highest heating surface in the boiler and the highest well into the upper part of the steam space.

Code Calling Systems. Code calling systems are used in large shipbuilding plants for the purpose of keeping executives in touch with one another as well as for locating any important man quickly in whatever part of the plant he may be.

Coefficient. A ratio between certain characteristics of a vessel which serves as a means of comparing that vessel with others. See particular coefficient desired.

Coefficient, Admiralty. A coefficient used in power estimating. The Admiralty coefficient is the cube root of the square of the displacement in tons times the square of the speed in knots divided by the indicated or shaft horsepower. The valve of the Admiralty coefficient is practically identical for similar ships at corresponding speeds.

Coefficient, Block. The ratio of the immersed volume of a ship to the product of the waterline length times the breadth at waterline times the draft to the top of keel.

Coefficient, Cylindrical. Same as prismatic coefficient. The ratio of the immersed volume of a vessel to the volume of a circumscribed cylinder. The cylinder may be circumscribed about the midship section with a length equal to the length of the vessel, in which case the longitudinal cylindrical coefficient results; or it may be circumscribed about the Ioad waterline with a length equal to the draft of the vessel, in which case the Vertical Cylindrical Coefficient results. The former is sometimes called the longitudinal coefficient and the latter the vertical coefficient. In case merely the term cylindrical coefficient is used without qualification invariably the longitudinal coefficient is referred to.

Coefficient, Displacement Length. The ratio of a vessel’s displacement, in tons, to 1/100 of its waterline length in feet cubed.

Coefficient of Fineness. The ratio of the area of a curve to the area of its circumscribed parallelogram. The coefficient of fineness is sometimes used in relation to a solid, in which case it is the ratio of the volume of the solid to the volume of a circumscribed rectilinear parallelopiped.

Coefficient, Longitudinal. The ratio of the immersed volume of a ship to the product of its waterline length and immersed area of midship section. Also called Prismatic Coefficient.

Coefficient, Midship Section. The ratio of the immersed area of the midship section to the area of a rectangle having sides equal respectively to the waterline breadth and draft at the midship section.

Coefficient, Prismatic. See Coefficient, Longitudinal.

Coefficient, Propulsive. The ratio between the effective horsepower and the Indicated horsepower or shaft horsepower at any given speed

Coefficient, Waterplane. The ratio which the area of a waterplane bears to its circumscribing rectangle.

Coffee Urn. A large receptacle used for boiling coffee.

Cofferdams. Void or empty spaces separating two or more compartments for the purposes of insulation, or to prevent the liquid contents of one compartment from entering another in the event of the failure of the walls of one to retain their tightness.

Coil. A term applied to a nest of piping. It may be composed of several pipes connected at the ends by headers or return bands, or it may consist of a continuous pipe which has been given a number of turns.

Coir Rope. See Rope, Coir.

Coke Forge. A forge in which coke is used as fuel.

Collar. As applied to machinery and machinery parts. A section of increased diameter in the form of a ring. As applied to ship structure, a piece of plate or a shape fitted round an opening for the passage of a continuous member through a bulkhead or floor plate to secure tightness against dust, water, air, etc.

Collar. See Collar, Angle. Applied to pieces of light plating formed to make a close fit around any beam at the point where it pierces a deck or bulkhead. Plate collars are used to obtain semi-watertightness, weather tightness and for finish.

Collar, Angle. Also called a staple. A term applied to a piece of angle bar that is forged or bent to form a close fit around a structural member.

Collier. A vessel designed for the carriage of coal. It may or may not be fitted with especial appliances for coal handling.

Collision Bulkhead. See Bulkhead, Collision.

Collision Mat. A large mat used to close an aperture in a vessel’s side resulting from collision. The mat is constructed of a double thickness of cotton canvas quilted together, body roped, and thrummed on one side with hemp thrums. Hogging and distance lines used in placing and securing the mat in position are fitted to cringles worked in each corner. The thrummed side of the mat is placed in contact with the skin of the ship.

Columns. See Pillars.

Columns, Engine. See Engine Columns.

Combination Punch and Shear. See Punch and Shear, Combination.

Combination Vise. See Vise, Combination.

Combustion Chamber. See Boiler Combustion Chamber.

Commutator. A copper cylinder composed of insulated segments mounted on the shaft of an electric motor or generator. The insulated segments are connected to the armature coils and are so arranged as to change the connections of the armature coils with the carbon brushes as the armature rotates.

Companion or Companion Way. A hatch or opening in a flat, deck or house top to provide access; principally for the personnel.

Compass, Dry. A compass without liquid in it, prior to the liquid compass as developed in the 19th century.

Compass, Gyroscopic. The gyroscopic compass is entirely different from the magnetic compass. The earth’s magnetism has nothing to do with its Indication of the meridian. The north seeking properties of the gyro-compass are derived from the peculiar properties of rotating bodies which in the case of the gyroscopic compass are electrically driven gyroscopic wheels. Any rapidly rotating body tends to place its axis parallel with that of the earth, which is, of course, North and South. We must modify the above statement by adding that any rapidly rotating body to do this must be supported so that it will have a freedom of motion in different directions. Such a device is known as a gyroscope. The gyroscopic compass may have one or more gyroscopes. The type used of recent times has two gyroscopes of equal size so arranged that when the ship is rolling, they will neutralize each other’s tendency for error. The directive force of a gyroscope, while 100 times more powerful than that of the magnetic needle, is still further amplified by an auxiliary electric motor, which is sufficiently powerful to operate the compass card in azimuth. Repeater compasses, installed wherever desired about the ship, are operated by the master compass containing the gyroscopes by a simple electric follow-up system. The master compass is usually located at almost the rolling axis of the ship in a protected place. The complete gyroscopic compass equipment consists of master compass, repeaters, control panel, and storage battery. The motor generator is used to transform the ship’s electric current into that suitable for the operation of the compass and the repeaters. The storage battery is for emergency use only and will store sufficient energy to operate the master compass for several hours in case of the failure of the ship’s supply. The gyroscopic compass is standard in all the navies of the world. It is fast being introduced in the merchant marine service, and has already been adapted by the Cunard Line on some ten of their vessels. It is also in use on the Royal Mail, the Lloyd Sebauda and the Canadian Pacific steamers.

Compass, Magnetic. The compass is the most important instrument of navigation in use on board ship, the path of a ship through the waters depending upon the efficient working and use of this instrument. There are two kinds of compasses, the Dry Card Compass and the Liquid Compass. The Dry Compass consists essentially of a number of magnetic needles suspended parallel to each other and fastened to the rim of a circular disc that has a paper cover upon which are marked the points of the compass and the degrees. This card rests upon a pivot centered in the compass bowl, which in its turn is suspended by gimbals in the binnacle or stand, the latter having means of lighting the card at night and for the adjustment of compass errors due to the magnetism of the ship. In the Liquid Compass, the bowl is filled with alcohol and water, or oil. The needles are sealed in parallel tubes and form a framework which connects the central boss with the outer rim, the whole resting upon a pivot in the compass bowl. Upon the rim are printed the points and degrees. As regards the relative uses of these compasses, it may be said that the dry compass is the standard in the world’s Merchant Marine, while the liquid compass is the standard in Navies, because of its freedom of vibration from the shock of gunfire, etc. The compass has been used for purposes of navigation since the third or fourth century, and the points of the compass were a natural development of subdivision of the card and have been in use since the fourteenth century. Capt. Flinders, R.N., was the first to investigate the laws of the deviation of the compass, and was the first to introduce the method of swinging ships for obtaining the deviation, in 1814. The construction of iron vessels and the consequent errors of the compass caused investigation, and in 1838-39 Sir George B. Airy, then Astronomer Royal for Great Britain, at the instigation of the Admiralty, conducted a series of experiments for "the purpose of discovering a correction for the deviation of the compass produced by the iron in the ship." The result of this investigation was immediately given to the world, and the principles then discovered form the basis of our compass knowledge of today. To the late Lord Kelvin, navigators the world over are indebted for his untiring work in the interests of practical navigation, and through his researches we have accurate knowledge of how a compass, its binnacle and accessories should be made, based upon scientific and mathematical formulae, and compasses so made are "Standard" for that instrument. Lord Kelvin laid down two fundamental principles:

1. In order that a compass may be capable of adjustment so as to be correct on all courses at any one part of the world, it is essential to use short needles.

2. In order that the compass so adjusted may be correct on all courses at all parts of the world, it is essential that the magnetic strength of the needle be small.

An efficient compass, therefore, embodies within itself the principles of construction as laid down by the late Lord Kelvin, and also means to carry out fully the principles of adjustment laid down by Sir George B. Airy, the whole being an instrument of rugged construction made to withstand the vibrations and shocks incidental to the movements of a ship, and, at the same time, so constructed as to keep from the delicate parts of the instrument the effects of these movements. As an accessory to the compass, means must be supplied for the taking of Azimuth or bearings of celestial and terrestrial objects. This is generally accomplished by means of a sight vane accurately centered on the compass and free to move in any direction. With this instrument, it should be possible to obtain an accurate bearing even though the vessel is yawning for several degrees each side of her course. The magnetic compass, when once installed and adjusted, is the only instrument used in the equipment of a vessel whose proper working does not depend upon human agencies and which will perform its proper functions for years without human aid.

Compass Lantern. A lantern used to illuminate the compass in the binnacle during darkness. Heat from the lantern was taken away by a funnel on top of the binnacle.

Compensator. See Auto-Transformer.

Compounds, Boiler. See Boiler Compounds.

Compounding of Stresses. The superimposing, one upon another, of the various stresses acting upon a member. In compounding stresses the directions in which the various components act must be considered.

Condensate Pump. See Pump, Condensate.

Condenser. A chamber of rectangular or cylindrical shape whose function is to convert the exhaust steam from the engine, turbines, and auxiliary machinery into water.

Condenser Air Cock. An air cock is usually installed on the front or back head to allow any accumulation of air to escape.

Condenser, Augmenter. A supplementary condenser installed between the main condenser and air pump. It is used in connection with a steam ejector to densify the air vapor and ejector steam and to increase the pressure in the air pump suction.

Condenser, Auxiliary. A condenser for the auxiliary machinery such as pumps, refrigerating machine, turbo generator engines, winches, steering engines, windlasses, etc.

Condenser Auxiliary Feed Connection. A short pipe line including a valve for the purpose of taking circulating water from the front head to the steam chamber. As the circulating water is usually salt, it should be used only in emergencies.

Condenser Back Head. A water chamber on the back end of the condenser. When the front head has one dividing wall there is none in the back head. Where there are two or more dividing walls in the front head there is always one less in the back head. Where there is an odd number of dividing walls for the front head the discharge chest for the circulating water is on that head. Where there is an even number of dividing walls in the front head the discharge chest must be in the back head. Bosses for inspection and hand holes should be fitted on the back head for such compartment therein.

Condenser Baffle Plate. Also called Diaphragm Plate. A thin plate fitted in the way of the exhaust steam inlet and perforated with numerous holes, the object being to fill the whole condenser with steam and to protect the tubes nearest the inlet.

Condenser Boiling Out Connection. A connection for the admission for live steam to the condensing chamber.

Condenser Cover Plate. A plate for covering the hand and inspection holes.

Condenser Diaphragm Plate. See Condenser Baffle Plate.

Condenser Doors and Hand Holes. Openings for inspection which are closed by cover plates.

Condenser Dry Suction. A pad or flange for connection to an air and vapor pump or to an air and vapor ejector. It is located on the side of a condenser and above the wet suction.

Condenser End Plate. A liner plate to which the tube sheets, front and back heads are attached.

Condenser Exhaust Nozzle. A casting, boss, or fitting attached to the shell of the condenser for the purpose of making a connection to the steam exhaust line from the engines or their auxiliaries.

Condenser Ferrule. See Condenser, Tube Ferrule.

Condenser Foundation. A term applied to the foundation supporting the condenser. There are usually two supports, one for the main and one for the auxiliary condenser.

Condenser Front Head. The chamber that receives the circulating water. It has one or more dividing walls causing the water to pass back and forth through the condenser tubes. Bosses for two or more hand and inspection holes should be fitted on this head. The front head is generally a casting.

Condenser Hanger. A hanging support for a condenser. Most commonly used to support the auxiliary condenser.

Condenser, Jet. A chamber usually of cone shape in which the steam and cold condensing water are mixed. The condensing water, upon entering the condenser, is forced to pass through a plate perforated with a large number of small holes. This forces the water into small jets and causes a more intimate mixture with the steam. This type is practicable only on fresh water or where a fresh supply of feed water is easily obtained. A better vacuum is obtained with the surface condenser.

Condenser, Keel. Pipes near the keel on the outside of the hull used for condensing steam. It is necessary that these pipes should be of a material that will not set up electrolysis with the shell, struts, stern frame and propeller.

Condenser, Main. A condenser for the main engines.

Condenser, Rotary. A synchronous motor or converter with over excited fields. This type of condenser is used when large capacity effect is desired.

Condenser Saddle Plate. See Condenser Foundation.

Condenser Shell. The outside wall of the condenser chamber. When the condenser is part of the engine frame the shell is generally rectangular in shape and made of cast steel or cast iron. When independent of the engine the shell is generally cylindrical, oval, or heart shaped and made of sheet steel or sheet brass.

Condenser Soda Cock. A connection for admitting soda or potash dissolved in water into the condenser. The object is to remove grease and dirt from the outside of the tubes. This is accomplished by boiling out this mixture with live steam.

Condenser, Static. A pair of electric conductors slightly separated by a dielectric. Two types of Electric Condensers are the flat type and the Leyden Jar. The Flat Type Condenser consists of tinfoil conductors separated by thin flat dielectric sheets (usually of Mica). The Leyden Jar consists of a glass jar, coated within and without two-thirds of its height with tinfoil, and a metallic rod protruding through the stopper of the jar and connected to the inner coat of tinfoil by means of a small chain.

Condenser Stay Rods. Steel rods running parallel to the tubes in the condenser chamber and serving the purpose of staying the flat tube sheets.

Condenser Suction Pads. Pads to provide connection for pumping the air and condenser steam from the condenser.

Condenser Supporting Plates. See Condenser Tube Rest Plates.

Condenser, Surface. A chamber in which steam is condensed by contact with the outside surface of a large number of thin brass tubes through which cold water is circulated. This produces a condensate of exhaust steam without the addition of any circulating water which is usually salt.

Condenser Tubes. The numerous small tubes closely fitted in a surface condenser. Thin brass tubes from about 5/8" to 3/4" outside diameter which run through the condenser chamber between tube sheets. The circulating water passes through them and the exhaust steam condenses on their outside surfaces.

Condenser Tube Ferrule. A cylindrical brass fitting used to secure the tubes in the tube sheets, threaded on the outside to fit the counter bore in the tube sheet and bored on the inner end to make a sliding fit over the condenser tubes. The outer end of the ferrule is tapered down so that its inside diameter is about the same as the inside diameter of the tubes. A slot is cut in the outer end for the purpose of screwing the ferrule down on packing which is placed between the bottom of the counter bore in tube sheet and the inside end of the ferrule. This method allows the tube or ferrule to be readily renewed.

Condenser Tube Plate. See Condenser Tubes Sheet.

Condenser Tube Rest Plates. Also called Supporting Plates. These plates serve the purpose of intermediate supports for the condenser tubes between the tube sheets.

Condenser Tube Sheet. A brass plate into which ends of condenser tubes are fastened. These sheets, one at each end of the condenser, serve as end boundaries for the steam space and supports for the tubes. They are made of brass and counterbored for a brass ferrule.

Condenser Vacuum Gauge. A tube graduated in inches of mercury for obtaining the absolute back pressure in the condenser.

Condenser Vanes. Thin sheet steel plates placed among the condenser tubes and running between tube sheets. The object is to secure as near a uniform distribution of the steam to the tubes as possible.

Condenser Water Chest. A casting fitted to the front head of the condenser to which the discharge line from the circulating pump is attached.

Condenser Water Inlet. The circulating water inlet on the front head.

Condenser Water Outlet. A boss, chest or fitting on the front or back head of the condenser, as the case may be, for connection to the overboard discharge line.

Condenser Wet Suction. A pad or flange for connection to a condensate pump or to a combined air and water pump. It is located in the lowest part of the condenser.

Condenser Zincs. Zinc plates fitted in the front and back head to offset galvanic action. They should have good metallic contact.

Conduit. Wrought iron pipe, fiber pipe, tile or other hollow products specially prepared to accommodate and protect electric wire and cable.

Conduit Box. A metal box so designed that one or more conduits may be connected to it and so arranged as to make the electric wire or cable in the conduit easily accessible. A conduit box for marine work is usually made water tight.

Conduit Pipe. A pipe enclosing and protecting electric wiring.

Condulet. A conduit fittings so arranged as to allow the wires or cables in the conduit to be connected, pulled through, or brought out of a conduit in accordance with the Underwriters’ Rules.

Connecting Bridge. See Bridge, Connecting.

Connecting Rod. That part of the reciprocating engine by means of which the reciprocating straight line motion of the piston is transformed into the rotary motion of the crank. It consists essentially of a metal rod having a head forged at its upper and a foot at its lower end for the purpose of taking the cross head and crank pins respectively. The openings in these end forgings are fitted with brasses and caps. Marine connecting rods generally increase in area of cross section from top to bottom, the section being sometimes circular and sometimes flattened in the plane vertical to the shaft line.

Conning Towers. Protective structures built up of armor plates and having various shapes and sizes. They are designed for the protection of the commanding officers of war vessels during naval actions. They are so located and designed as to command the best possible unobstructed view, while at the same time affording satisfactory protection.

Continuous Floors. See Floors, Continuous.

Contline (of a rope). The sunken space or groove following the lay of the rope between the strands.

Contracting Ship-fitter. A slip-fitter who takes a contract to lay out the material for some structural feature of the ship, as a keel, a deck, or the shell plating, and to set it up on the ship ready for riveting.

Controller, Motor. Controllers for electric motors include such apparatus as starting rheostats, speed regulating or controlling rheostats and such devices as compensator or auto-transformer types of motion starting apparatus, which are used for alternating current motors. There are also special types of switches, such as float and tank switches, magnetically operated switches, star-delta switches used with squirrel-cage induction motors, and various other styles used for controlling the motor. Automatically operated motor starters, regulators and controllers are also included under this heading. A motor of very small power can be started without the need of a starting rheostat, but for most motors used aboard ship and in the shipyard, starting or regulating devices of some kind are required.

Converter, Synchronous. Synchronous Converter.

Cooler Pump. See Pump, Cooler.

Coping Machine. A machine designed to cut away the flanges and corners of beams.

Copper Sheathing. See Sheathed.

Coppers. Galley steam kettles. These always used to be made of copper, hence the name.

Coppersmith. A workman who fashions or fabricates the various fittings or parts, which are made from copper piping, tubing or sheets.

Cordage. A comprehensive term for all ropes of what ever size or kind on board a ship.

Core Oven. See Oven, Core.

Cornice. An interior or exterior projection fitted along the upper edge of a deck house to form an ornamental appearance.

Corresponding Speeds. Speeds which bear the same relation to each other as that of the square roots of the linear dimensions of the ships involved. The foregoing presupposes the existence of similarity between the ships so that the wave formations resulting are similar.

Corrosion. Described under Steel and Iron.

Corrugated Bulkheads. See Bulkheads, Corrugated.

Corrugated Furnace. See Furnace, Corrugated.

Cosmolabe. This resembled an Astrolabe and was employed for astronomical observations.

Cotton Rope. See Rope, Cotton.

Coulomb. The practical unit of quantity of electricity. It represents the quantity of electricity that passes through the cross section of a conductor per second when the current strength is 1 ampere. It is also equal to the quantity of electricity contained in a condenser with a capacity of one farad, when the same is subject to an electric motive force of one volt.

Counter. That part of a ship’s after body extending aft from the after perpendicular (usually above the water line).

Counter bore. A tool used for enlarging a hole without changing its relative position; also a term applied where a hole is rebored to a larger diameter for part of its length.

Counter Electromotive Force. The induced electromotive force in the armature circuit of an electric motor which tends to cause the current to flow in to opposite direction to the current in the line.

Countersink. A term applied to the operation of cutting the sides of a drilled or punched hole into to shape of a frustum of a cone. This shape provides a shoulder for a rivet or a bolt and allows a flush surface to be maintained. Also applied to the tool doing the work.

Counter sinkers. Men who operate hand or power tools which taper or countersink holes in material.

Countersinking Machine. A drilling machine becomes a countersinking machine when a countersink is used instead of a drill.

Countersinking Machine, Portable. A portable pneumatic drilling machine becomes a countersinking machine when a countersink is used instead of a drill. A small truck built in the form of a box and weighted with pig or scrap metal. Small wheels are fitted to one end and a pneumatic machine with a countersink attached to the other end. Handles are fitted to the machine end. By raising the handles the truck may be rolled along plates laid on the floor. The machine is started and run continuously from beginning operation until a job is finished, the holes being countersunk by rolling the truck into position and lowering the handles until the desired depth of countersink is reached.

Countersunk. A term applied where the end of a hole is chamfered off, the usual slope being 45°.

Counter Timbers. See Timbers, Counter.

Coupling. A device intended for securing together adjoining ends of piping, shafting, etc. A flange coupling, used for line shafting, consists of an enlargement of the shaft end in the form of a disc or flange, the two flanges which terminate the adjoining shaft sections being securely attached to each other by body bound bolts. A socket coupling, used in twin screw vessels for the section of line shaft just inboard of shaft tube stuffing box, consists of a tapered end on the forward end of the outward section inserted in a socket worked in the after end of the inboard section, both being secured to each other by a key and locking ring. A flexible coupling, used sometimes with reciprocating engines, is similar to the flange coupling except that the face of one flange is given the shape of a spherical segment, centered on the face of the other by a ball and socket joint, and secured to the other flange by bolts, the nuts of which bear on springs so as to take up lost motion. Piping is joined by flange couplings similar to those described above and by threaded sleeves.

Coupling Bolts. Bolts intended for use with couplings. Their form varies with the type of coupling from the body bound bolt secured with nut and pin in a rigid flange coupling to the tap bolt of the socket coupling or the bolt and nut of the flexible coupling.

Coupling Bolt Forcer. See Bolt Forcer.

Coupling, Pipe. A wrought iron sleeve, having an inside thread used to make a joint between two pipes. Where it is not desirable to disturb the position of the pipes in making the joint, unions should be used.

Coupling, Rudder. See Rudder, Coupling.

Course. The path over which a vessel proceeds. Some courses used habitually are known by name. This applies especially to measured mile courses, where trial trips are conducted and to racing courses. In the open sea the course is designated by the point of the compass toward which the vessel is headed.

Cover, Boat. A Piece of canvas used as a cover for a small boat when it is not in use.

Cover, Hatch. See Hatch Cover.

Covering Board. A term applied to the plank fitted horizontally on top of frames and waterway board at the weather decks of wood ships.

Covering, Deck. See Deck Covering, Decking.

Cowl. See Ventilators, Bell Mouthed or Cowl.

Coxswain. A petty officer or sailor, who steers or has charge of a small boat.

Crab Winch. See Winch, Crab.

Cradle. The structure of wood or wood and steel with its lashings that is built between the top of the sliding ways and the shell of a ship. The part adjacent to the shell is carefully fitted in order to distribute evenly the stresses due to launching.

Cradle, Launching. A timber frame work built up to support and partly incase a vessel when it is launched.

Craft. A vessel of any type.

Crane. A machine used for hoisting and moving pieces of material or portions of structures or machines that are too heavy to be handled by hand or that are heavy enough to make handling by hand uneconomical.

Crane, Bridge. An overhead type of crane usually installed in shop buildings. This type generally consists of one or more girders mounted on trucks with wheels which run along tracks supported by the columns of the building. A carriage containing or supporting the hoisting apparatus is designed to travel across the beam providing in this manner for lateral motion. Bridge cranes designed for small loads are often operated by hand while those designed for the heavier loads are generally operated by electric motors. Electrically operated cranes are generally operated from a cab attached to the girders.

Crane, Bucket Handling. A crane designed to operate a bucket for excavating or handling coal, mud, etc.

Crane, Gantry. An elevated structure designed to travel along rails on the ground level and provided with a hoisting gear.

Crane, Jib. A boom or arm fitted to swing in sockets attached to a wall or column. The boom in this type of crane is generally fixed in a vertical direction but free to move horizontally.

Crane, Locomotive. A self-propelling car with a crane mounted upon it.

Crane, Traveling. See Crane, Locomotive, and Crane, Bridge.

Cranemen. Men who operate overhead cranes handling material in the yard or shop.

Crank Arm or Web. That portion of the crank or crank shaft which connects the crank pin and crank axle. It forms the lever by means of which the force exerted on the crank pin by the connecting rod is transmitted to and utilized in turning the shaft in its bearings. In engines of more than one cylinder the angles which the several crank arms make with each other are matters of careful consideration in order to make possible the obtaining of the most uniform torque possible throughout the entire revolution of the shaft.

Crank Axle. The cylindrical portion or portion of the crank or crank shaft by means of which all the members of the rotating system of the engine are carried and held in place.

Crank Pin. The cylindrical member, forming part of the crank, to which the foot of the connecting rod attaches and which receives the direct exert of the connecting rod. Its design receives the most thorough consideration because of the character and severity of the strains to which it is subjected.

Crank Shaft. That portion of a reciprocating engine in which rotary as distinguished from rectilinear motion first appears. The term is applied to the portion of the shaft which (depending upon the number of cylinders) is composed of one or more cranks rigidly attached to one another and arranged to work about a common axis viz.: that of the propeller shaft. Crank shafting may be either built up or forged. Built up crank shafts are composed of a series of crank pins, crank axles, and crank webs formed separately and shrunk and keyed together. This type is common in merchant practice where might is not of first importance. It lends itself readily to fabrication and repair. Forged crank shafting is cut and machined from a single forging. It effects a saving in weight over the built-up type and is becoming more popular. It is at the present time universally used in naval practice and in high grade work outside naval practice.

Crank Shaper. See Shaper, Crank.

Crank or Tender. That quality by which a vessel assumes large angles of heel as a result of the action of comparatively small forces. It is the result of a small metacentric height.

Cribbing. Foundations of heavy blocks and timbers for supporting a vessel during the period of construction.

Cringles. Iron thimbles or grommets worked into or attached to the edge, head, leech, or clew of a sail for making fast the bowline, bridles, earrings, sheets, etc.

Critical Docking Draft. That draft at which a vessel loses her initial stability when being docked. When the draft of a vessel in process of docking or undocking is less than the critical docking draft either bilge blocks or shores must be in place to prevent the development of a list.

Critical Speed. Same as Squatting Speed.

Cross. A pipe fitting composed of four braces, so constructed that one pair is on one axis and the other pair is on another axis, the axies being at right angles.

Cross Beams, Hatch. A term applied to the portable athwartship beams in a hatch that support the fore and after which in turn support the hatch covers. Also applied where these beams support the hatch covers directly without fore and afters, in which case the hatch covers must run fore and aft.

Cross Curves of Stability. A series of curves of righting arm plotted to a base of displacement, each curve being drawn for a given degree of heel. In preparing such a series of curves it is customary to assume all displacements an axis or point of reference at fixed distance above the vessel’s base, and to compute the values of righting arm from this axis. The ordinary curve of statically stability corresponding to any loading may be derived by correcting the righting arms as taken from the cross curves for the various angles of heel at the proper displacement by an amount equal in each case to the deference between the correct height of the center of gravity and the height of the axis or base assumed for the cross curve multiplied by the sine of the angle of the cross curve.

Crosshead. That part of a reciprocating engine which attaches directly to the outer end of the piston rod and acts at once as the connection between piston and connecting rod and as a guide to the former to keep it in line with the axis of the cylinder in spite of the transverse component set up by the connecting rod due to its angular position. The crosshead of the usual marine type consists essentially of a body into which the piston rod is screwed and secured by a nut. From this body extend pins to take the jaws of the connecting rod and at right angles to these pins (termed crosshead pins) extend arms to carry the slides for the maintenance of proper alignment.

Crosshead Guide Bars. Parallel, fixed members between which the crosshead works, it being held to a straight line reciprocating motion by means of the crosshead guides or slippers bearing against the guide bars. These members are made of cast iron carefully finished.

Crosshead Nut. A nut intended to secure the piston rod against turning in or out of the cross head.

Crossing the Line Certificate. A mock certificate issued aboard ship to a passenger who had crossed the equator for the first time and had undergone the somewhat harrowing but humorous "crossing the line" ceremony. A crew member arrayed as Father Neptune would perform the ceremony with the glad help of other veterans. Much ducking and mock shaving was involved.

Crossjack. The lowest yard carried on the mizzen mast of a vessel. Sometimes used with reference to the sail carried by this yard.

Cross-Over. A pipe fitting or a pipe, having a double offset which is used to allow one pipe to pass over another.

Cross-staff. This simple instrument was also known as the fore-staff, baculus, balestilla, and arballista, being thus called because of its resemblance to a cross-bow and its use for taking a sun-sight (hence the expression "shooting the sun"). Originally an astronomer’s aid, it was adopted by mariners for measuring the angle of the altitude of the sun above the horizon at sea. One more name for it was Jacob’s Staff, thanks to its physical resemblance to the constellation Orion, formerly Jacob on medieval star maps.

Cross-Trees. A term applied to athwartship pieces fitted over the trees on a mast. They serve as a foundation for a platform at the top of a mast or as a support for outriggers.

Crown. Term sometimes used denoting the round up or camber of a deck. The crown of an anchor is located where the arms are welded to the shank.

Crown Sheet, Boiler. See Boiler Crown Sheet.

Crows Nest. A lookout station attached to or near the head of a mast.

Cruiser. A vessel designed to keep at sea for extended periods. Such scantlings are fixed and type of machinery selected as will insure exceptional seaworthiness. A war vessel in which the protection against gun fire is more or less sacrificed for speed or lower radius of movement.

Cruising Turbine. See Turbine, Cruising.

Crutch. A term applied to a support or boom. Also applied to the jaw of a boom or gaff.

Cuddy. A galley structure on deck; a small cabin.

Curve of Areas of Midship Section. A curve indicating the area of midship section below any waterline under consideration.

Curve of Areas of Water Plane. A curve indicating the area of water plane corresponding to any draft.

Curve of Center of Gravity of Water Plane. A curve indicating the longitudinal position of the center of gravity of the ship’s water plane for any and all drafts.

Curve of Displacement, Fresh. Same as Curve of Displacement, Salt Water; excepting that the ship is considered as floating in fresh water of thirty-six cubic feet per ton.

Curve of Displacement, Salt. A curve which indicates for any draft the corresponding displacement of the vessel, the ship being considered as floating at designed trim in salt water of thirty-five cubic feet per ton.

Curve of Longitudinal Center of Buoyancy. A curve so plotted as to show the variation in value of the distance of the vessel’s center of buoyancy from a given reference line (generally the half length) measured in a fore-and-aft direction and corresponding to variations in draft and displacement.

Curve of Longitudinal Metacenter. A curve so plotted as to show the variation in value of the longitudinal metacentric radius or of the height of the longitudinal metacenter above base corresponding to variations in draft and displacement.

Curve of Moment to Alter Trim. A curve which indicates the approximate moment in foot tons which at any draft is required to alter the trim of the vessel by one inch.

Curve of Sectional Areas. A curve, plotted from a straight base line, representing the length of the ship, the ordinates of which represent to scale the areas of the vessel’s immersed cross sections at corresponding points. The area under this curve represents to scale the volume of the displacement. The center of gravity of this area represents the longitudinal center of buoyancy of the displacement.

Curve of Tons per Inch of Immersion. A curve indicating for any draft the number of tons of additional load which would be required to immerse the vessel one additional inch.

Curve of Transverse Metacenter. A curve so plotted as to show the variation in value of the transverse metacentric radius or of the height of the transverse metacenter above base corresponding to variations in draft and displacement.

Curve of Vertical Center of Buoyancy. A curve so plotted as to show the variation in value of the distance of the vessel’s center of buoyancy measured vertically above or below a horizontal reference line (generally the molded base or the plane of flotation) and corresponding to variations in draft and displacement.

Cutter. A boat carried by war vessels.

Cutters or Burners. Workmen who operate gas cutting tools to sever, trim or cut away surplus metal.

Cutwater. A timber bolted to the forward side of the stem in wood ships. The forward edge of the stem in steel vessels is also called the cut-water.

Cylinder. That portion of the reciprocating engine in which the steam acts to force the piston from one end to the other and vice-versa. The name is derived from its internal shape inasmuch as its exterior is complicated by various attachments and additions. The cylinder is made of the highest grade of cast iron, the interior being carefully bored to a smooth cylindrical shape for the passage of the piston. With the barrel of the cylinder are usually cast the lower head, valve casings, chests, ports, passages, etc., also the lugs for the attachment of the columns, braces, etc. The upper head or cover is cast separately and attached to the barrel by means of studs and nuts. The lower cover is fitted with a stuffing box and gland to permit the free passage of the piston rod but to prevent the escape of steam. The interior faces of the piston covers are so shaped as to conform closely to the contour of the piston faces in order to cut down the volume of clearance as much as practicable. Frequently the inner surface of the cylinder barrel is formed by a liner cast of fine grained extra hard iron. It is then possible to replace the liner in case of excessive wear. Such a liner also forms one side of the jacket space in case the cylinder is to be steam jacketed. In case steam jacketing is contemplated all joints must be carefully made in order to avoid steam leaks. In the ordinary triple expansion engine with three cylinders, the cylinders are known as high pressure, intermediate and low pressure respectively.

Cylindrical Coefficient. See Coefficient, Cylindrical.

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