Maritime Dictionary – Everything that Starts with “C”

by | Last updated Nov 24, 2023 | Maritime Dictionary | 0 comments

C ▬ ● ▬ ●

C – Code flag; Affirmative. Sound signal; Affirmative.

C flag + three numerals –  Course.

Cab – Name given to screened shelter at wing of a navigating bridge.

Caban or Cabane – Old spelling of ‘Cabin’.

Cabin – Small compartment in a ship set apart for use of an officer, passenger or other person. The living accommodation on a vessel.

Cabin Boy – Junior rating whose duty is to attend on officers of a ship. Title is obsolescent. At one time he was a protege in the retinue of an admiral; as such he was the forerunner of the midshipman.

Cabin Passenger – Person who has paid at least £25 for his passage (or £3 25p for every 1000 miles), has at least 36 clear square feet of space for his exclusive use and has a signed contract ticket. It also distinguishes the cabin passenger from the deck, steerage, pilgrim or emigrant all of whom are passengers.

Cabin sole – The decking of the cabin that you walk on.

Cable – Nautical unit of distance, having a standard value of 1/ 10th of a nautical mile (608 ft.) or 100 fathoms. For practical purposes a value of 200 yards is commonly used. 2. Rope of more than 10 inches in circumference and made of three right-handed ropes laid up left handed. These were used for attachment to anchor before chain cable was manufactured, and were up to 36 inches, or more, in

Cable Bends – Two small ropes used for lashing end of hemp cable to its own part after it had been bent to anchor ring.

Cable Certificate – Signed document stating strength of cable supplied to a ship.

Cable Clamp – See bulldog clip.

Cable Clench – Strong steel forging fitted at bottom of cable locker for securing inboard end of cable. Is securely attached to ship’s structure, vertically below navel pipe, and is tested to 20 per cent above proof strength of cable.

Cable Flags – See ‘Anchor Flags’.

Cable Holder – Horizontal drum having sprockets to take link of cable. Is frictionally connected to spindle geared to capstan engine. Each cable has its own holder, thus allowing for independent veering or heaving.

Cable Hook – ‘Devil’s Claw’.

Cable Jack – Long steel lever fitted with a fulcrum. Used for slightly-lifting cable when a slip has to be passed under it.

Cable Laid – Said of ropes made by laying up three ropes so that they make one large rope.

Cable Locker – Compartment in which cable is stowed and the inboard end secured.

Cable Nipper – Short length of small rope, sennit or selvagee that was used for temporarily lashing a messenger to a cable when heaving in. Alternatively, an iron nipper, consisting of two shaped bars, hinged at one end, were used with chain cables and a chain messenger.

Cable Party – Part of a watch, or specially selected men, detailed to work cable.

Cable Shackle – Special shackle used for joining lengths of cable. Pin is flush with sides of shackle and is secured by a metal or wood pin passing through lug and pin.

Cable Ships – Vessels specially fitted for laying and repairing submarine telegraph cables. They have a large vertical sheave at stem head or at the stern or both.

Cable Stopper – Short length of very strong rope, securely attached to deck, with stopper knot at outboard end. Cable was lashed to it while inboard part was passed around the riding bitts.

Cable Tire – The coils of a rope cable.

Caboose – Old name for cook’s galley. At one time was applied to the funnel casing. Now applied to any small enclosed space.

Cabotage – Coasting trade. Reservation of such trade to flag nationals.

Caburns – Small spunyarn line used for serving rope cables to prevent chafe. Also used for seizings.

Cachalot – Sperm whale. Length up to 70 feet. Lives in ‘schools’; one school of females, or cows, and another of immature bulls.

Cadet – A young maritime worker trainee.

Caecias – See classical winds.

Cage Mast – Lattice mast of steel tubes formed into a criss-cross spiral, held at intervals by horizontal rings. Fitted to U. S. battleships of early twentieth century.

Caique – Light craft of Bosphorus, propelled by oars or sail. Else where in the Mediterranean a two-masted cargo-carrying vessel.

Cairn – A mound of stones often built as a memorial or conspicuous mark.

Caisson – Steel floating structure that can be flooded and sunk to close entrance to a dry dock. In engineering, is a watertight casing in which men can work under water.

Caisson Disease – Diver’s palsy, or bends. Paralysis caused by the formation of air bubbles in blood of a diver coming to surface too quickly after working at considerable depth, or under unusual air pressure. If bubble reaches the heart, the man dies at once: if it forms on brain or spinal cord there is paralysis of legs.

Calcareous – Word used to denote quality of bottom when of limestone. Fragments of shell, coral and minute skeletons may often be seen.

Calculated Altitude – Angular height of a celestial body above the horizon calculated as opposed to worked from sight reduction tables.

Calendar – Presentation of civil time in days, weeks, months and years.

Calendar Line – Alternative name for ‘Date Line’.

Calendar Month – Interval between any given date and 00 hrs. of the same date in the following month.

Calibration – Determination of error, if any, between the value indicated by an instrument and the actual value that it should indicate.

California Current – Name used in U. S. A. for ‘Mexico Current.’

Calima – A dusty wind off the Sahara that blows over the Canary Islands in winter.

Caliper – Pair of bowed legs, working on a common pivot, used for measuring internal or external diameters of circular items. Size of chain cable is measured with it.

Calk – Old astrological word for the calculating of a horoscope. 2. Old spelling of ‘Caulk’.

Call – Small whistle, of a special type, used by boatswains’ mates— occasionally by a commissioned boatswain—in Royal Navy when passing orders or piping the side.

Call Boy – Junior rating in Royal Navy whose duty is to repeat all orders piped by boatswain’s mate.

Call Sign – A ship’s unique identifying code.

Callipers – Calipers.

Callippic Cycle – Period of 27, 759 days, or 940 lunations, being approximately 76 years. New and full Moons occur on same day and date—within about 6hours. Calculated by Callippus (Greek), about 350 B. C., as an improvement on Metonic Cycle.

Calm – Absence of wind. No agitation of sea surface. See Beaufort scale.

Calorie – Amount of heat necessary to raise temperature of one gramme of pure water through one degree Centigrade.

Calorific Value – Number of heat units obtained by complete combustion of unit amount of fuel. Generally expressed as number of British Thermal Units (B. T. U.) per Ib. of fuel.

Calorimeter. Apparatus for determining specific heat of a substance by finding how much heat is lost or gained when its temperature is changed in standardised circumstances.

Calving – Breaking away of a mass of ice from a glacier or iceberg.

Cam – Projection on wheel or curved plate when shaped to give an alternating or eccentric movement to another member that is in contact.

Cam Cleat – Sprung loaded mechanism whose jaws will jam a rope under strain.

Cam Shaft – Shaft carrying a cam.

Cam Wheel – Wheel eccentrically mounted to transmit an alternating movement.

Camber Keel – Keel so shaped that its depth increases as it approaches the forward and after ends.

Camber – Roundness of deck that sheds water. Fullness of sail created by sail maker; also called draught. It can be altered by bending the mast’s middle forwards and bending the

Camel – A tank that is sunk and attached to a wreck, subsequently being filled with air to refloat it. A decked vessel with high stability for use in lifting sunken structures. A wooden float between a vessel and a dock used as a fender.

Can Buoy – Buoy with flat top above water.

Can Hooks – Two flat hooks running freely on a wire or chain sling. Hooks are put under chime of casks, weight is taken on chain sling or wire. Weight of lift prevents unhooking.

Canal – An artificial waterway used for the passage of ships or boats. A dug or dredged waterway.

Canals of Mars – Name given to lines of dark spots on surface of Mars. Suggestions has been made that they are irrigation canals, but this is not now accepted.

Canaries Current: A cool North Atlantic current setting southerly along the North African Western coastline.

Cancelling Clause – Inserted in a charter party, or other document, to entitle one party to withdraw from the contract if specified conditions are not observed.

Cancelling Date – In a charter party, is latest date at which a chartered ship must be ready to commence to fulfil terms of the charter.

Cancer – Latin for ‘crab’. Constellation situated about R. A. 9h and Dec. 10°- 13°N. Has no star brighter than Mag. 4. 2. Fourth sign of Zodiac, extending from 90° to 120° celestial longitude. Sun is in this sign from June 21 to July 22 (abt.).

Candela – A unit measure of luminous intensity based on a comparison with a candles brightness (candle power). 1 candela =0. 98 candles.

Cane Fender – Large bundles of canes bound together and used to protect ship’s side from chafing when alongside wharf, quay or another vessel. Hazel rod fenders are frequently called by this name.

Canes Venateci – ‘Hunting dogs.’ Constellation between Bootes and Ursa Major. Brightest star is Cor Caroli, Mag. 3.

Canicula – Latin for ‘Dog Star’. Alternative name for Sinus. Name is sometimes given to constellation ‘Canis Major’.

Canis Major – Latin for ‘Greater Dog’. Constellation S. E. of Orion. Brightest star is Sirius Mag.—1.6.

Canis Minor – Latin for ‘Lesser Dog’. Constellation E. of Orion. Brightest star is Procyon, Mag. 0.5. Canoe – Narrow-beamed craft propelled by paddles. Vary widely in construction from primitive dug-out to the Eskimo kayak and oomiak.

Canoe Rig –The sail arrangement of a canoe. There is no fixed type, but sails are arranged to keep centre of effort as low as possible. To avoid moving about in these tender craft much ingenuity is needed in arrangements for trimming, reefing and furling sail.

Canopus – Star α Argus. S. H. A. 264°; Dec. S53°; Mag. -0.9. Diameter is 180 times that of Sun; candlepower is 180 times greater; distant 650 light years. Named after Egyptian god of water, or the city of same name.

Canopy – Canvas cover on metal frames. Placed over a hatch or companionway, and in other places.

Cant – Corner or angle. One of segments forming a side piece in head of cask. 2. To tilt in the vertical plane, or to incline in horizontal plane. 3. Cut made between neck and fins of whale so that a hook can be attached for canting. 4. To roll-over a whale when flensing.

Cant Beam – Beams supporting the deck plating or planking in the overhanging part of the stern of a vessel.

Cant Blocks – Purchase blocks used when canting whales.

Cant Body  where the planes of a vessel’s frames are not at right angles to its centreline.

Cant Falls – Purchases used to sling a whale alongside.

Cant Frames – Short frames that support the overhanging counter of a vessel with an elliptical stern.

Cant Hook – Lever with hook in lifting end. Used for lifting heavy weights.

Cant Piece – ‘Cant timber.’ Also, piece of timber put along edge or a side fish to strengthen it.

Cant Purchase – Flensing purchase extending from mainmast head to a cut in a whale.

Cant Ribbon – That part of a gilded or painted moulding, along a ship’s side, that sweeps upward towards stem or stern.

Cant Timber Abaft – Projection of after cant timber, which formed a chock on which spanker boom rested when not in use.

Cant Timbers – Timbers, at extreme ends of a vessel, that are not perpendicular to keel; those forward leaning slightly aft, those aft leaning slightly forward.

Cantick Quoin – Triangular piece of wood used to prevent rolling of a cask.

Cantilever Beam – Girder with one end unsupported, and depending on its girder strength to bear stresses on unsupported end.

Cantline – Groove between strands of a rope. 2. Groove between casks or bags when stowed in rows.

Canton – Square division of a flag at its corner or corners.

Canvas – Material made from flax, jute, cotton or hemp. Supplied in bolts of approximately 40 yards. Usually 24 in. wide, but up to 72 in. in some materials. Graded in numbers from 0 to 7, 0 being the heaviest.

Canvas Covered – A technique of covering timber or ply with painted canvas to waterproof a deck etc.

Canyon – A deep gorge or ravine with steep sides.

Cap – Fitting over the head of a mast, and in which a mast above can be moved or confined.

Cap a Rope – To cover the end with tarred canvas, or hessian, and then whip it.

Cap Shroud – Supporting wires from either side of a mast leading over spreaders to support its upper sections.

Capabar  Old name for misappropriation of Government stores.

Capacitor – A temporary electrical storage device that blocks DC flow while allowing AC oscillations.

Capacity Plan – Plan and/or sectional elevation of a vessel showing capacities of all holds, bunkers, tanks, and other relevant compartments.

Cape – A projection of land into the sea.

Cape Horn Fever – Feigned illness of an incompetent seaman in cold and stormy weather.

Cape Stiff – Seaman’s nickname for ‘Cape Horn’.

Capelin – A small bait fish, N. Atlantic, also called caplin.

Capella – Star α Aurigae. S. H. A. 282°; Dec. N 46°; Mag. 0.2. Diameter is 12 times that of Sun; candlepower is 150 times greater; distant 47 light years; temp. 5500°A. Is a double star, the one seen being Capella A. Name is Latin for ‘Little Goat’.

Capesize – A large cargo vessel that cannot transit either the Panama or Suez Canals, typically greater than 120 000-180 000 DWT.

Capful of Wind – Passing wind of no great strength.

Caph – Star β Cassiopeiae. S. H. A. 359°; Dec. N 59°; Mag. 2 1/2.

Capital Ship – The most powerful contemporary type of warship.

Cappanus – Sea worm that attacks ship’s wooden bottoms and attaches itself to them.

Capricornus – (Lat. = Goat) Constellation situated between R. A. s 20 h 15m and 21 h 45 m and Dec. 12°—27° S. Has no star brighter than Mag. 3. Tenth sign of Zodiac extending from 270° to 300° celestial longitude. Sun is in this sign from Dec. 22 to Jan. 21 (about).

Capshore – Small spar supporting overhanging part of mast cap; heel being secured in a shoe on foremost crosstree.

Capsize – To overturn or upset. Said to be derived from words meaning ‘to move a barrel by turning it on head and bilge alternatively’.

Capsize (a Coil) – To turn over a coil of rope so that working end is on deck.

Capstan – Vertical barrel, working on a vertical spindle that is used for heaving on ropes and chain cable. May be operated by hand or by steam, electric or hydraulic engine. Top of barrel has square sockets in which capstan bars may be shipped when working by hand. Lower edge of barrel carries pawls which work in a pawl rack on deck, and prevent capstan walking back.

Capstan Bar – Stout wooden bar, often with an iron shoe, fitting into sockets of capstan when working capstan by hand. Outer end may be notched to take a ‘Capstan swifter’.

Capstan Bar Pin – Strong pin passing through head of capstan and end of a shipped capstan bar. Prevents capstan bar becoming unshipped.

Capstan Swifter – Rope having a cut splice in middle and a thimble in one end. Cut splice is passed over top of notch of capstan bar, swifter is back hitched over end of the other bars and swifter is then set up to its opposite part. This results in bars being firmly secured with an upward cant.

Captain – Master of a ship or pilot-in-command of an aircraft, commanding officer of a warship or an operator of any other vessel.

Captain of Top – Petty officer who is responsible to Commander for upkeep of a certain part of the ship, and for the hands allotted to that part.

Capture – Forcible taking of a vessel as prize, or reprisal, in time of war.

Caput Draconis – ‘Head of the dragon.’ Name sometimes given to Star α Draconis.

Car Carrier – Special purpose vessel for transporting cars.

Car Deck – A deck on which cars are carried.

Carack/ Carrack – Large 15th-century ship with high bow and stem castles.

Caravel – Spanish and Portuguese sailing vessel of Moorish origin. Was broad beamed with fore and after castles. Usually square rigged forward, lateen rigged on after masts. Both Columbus and Magellan used them. Name was given also to a small herring fishery boat of France.

Carbon Ceramic Seal – A pump seal consisting of a sprung carbon shaft ring closing onto a ceramic pump body seat.

Carbon Dioxide – A natural atmospheric gas (CO2) that is increasing due to man’s activities and contributing to the greenhouse effect.

Carbon Fibre – An immensely strong costly material of high tensile strength. Used for yacht masts.

Carbon Monoxide – A deadly product of combustion (CO).

Cardinal Points – Of compass: North, South, East, West. Named after cardinal points of horizon. 2. Of horizon: points in which horizon is cut by meridian and prime vertical. 3. Of Ecliptic: points in which Ecliptic is cut by secondary circles passing through the equinoctial and solstitial points

Careen – To list a vessel so that a large part of her bottom is above water. Formerly done to remove weed and marine growth, to examine the bottom, to repair it and to put on preservative or anti-fouling. Still done with small craft.

Cargazon – Old name for ‘Bill of Lading’. Spanish.

Cargo – Goods or merchandise loaded into a ship for carriage.

Cargo Battens – Wood battens, portable or fixed, in hold of a cargo vessel to keep cargo away from ship’s side and to allow necessary through ventilation.

Cargo Book – Book kept by master of a coasting vessel. Gives full particulars of all cargo carried, name of consignee and name of consignor—if known.

Cargo Handling – The act of loading and discharging a cargo ship.

Cargo Manifest – A list of all cargo carried on a specific vessel voyage.

Cargo Net – Large square net, of wire or rope, used when making up a hoist of small packages for loading or discharging.

Cargo Plan – Diagrammatic outline of a vessel, either vertically or horizontally, in which holds and cargo spaces are exaggerated, and machinery and accommodation spaces are diminished. Used for readily indicating positions of different cargoes, parcels and consignments.

Cargo Port – Watertight door in ship’s side. Used for passing cargo inboard and outboard in certain types of ship.

Cargo Preference – Reserving a portion of a nation’s imports and exports to national flag vessels.

Cargo Register – See Cargo manifest.

Cargo Sweat – Condensation formed on cargo when transported from cold climates to warm.

Caribbean Sea – Area between Central American continent and Yucatan Strait, the Greater Antilles and a line, on eastward of Lesser Antilles, that ends at Baja Point, Venezuela.

Carlins (-ings) – Fore and aft members that support the ends of beams that have been cut to form a hatchway or other opening. 2. Wooden sections, about 5 in. by 5 in., lying fore and aft below beams and carrying ledges on which decks of wooden ships are laid.

Carmilhan – Phantom ship of the Baltic. Somewhat similar to the ‘Flying Dutchman’.

Carney – Seaman’s term for hypocrisy. Said to be the name of a notorious master who was bland ashore but a fiend afloat.

Carpenter – Commissioned officer in R. N., petty officer in Merchant Navy, who is responsible for minor repairs and all woodwork in a ship.

Carpenter’s Stopper – Portable fitting for holding a wire under stress. Consists of a clamp—secured to any fixture by chains-and a shaped wedge that fits rope. Any surging of rope causes wedge to move further into clamp, and so increase nip.

Carpenters Trunk – Access to side lights cabinet.

Carrack – Historic large Portuguese sailing merchantman with fortified stern castle.

Carrick Bend – Method of joining ends of two ropes by turning the end of one rope over its own part and then passing the end of the other rope through the bight thus formed, over the cross in the first rope and then back through the loop on that side that is opposite to the one on which the first end is lying.

Carrick Bitts – Strong timbers in which a windlass is mounted. Carrier. Owner or charterer who enters into a contract of carriage with a shipper. 2. Ship carrying cargo. 3. An aircraft carrier.

Carrier – Owners or operators of vessels providing transportation to shippers. The term is also used to refer to the vessels. Abbreviation of aircraft carrier.

Carronade – Gun throwing a medium weight shot 600 yards with fairly high velocity. First made at Carron in 1779. Compared with cannon, shorter range but heavier shot.

Carry Away – To break, part or fracture.

Carry On – To continue sailing under the same canvas despite the worsening of the wind. To proceed.

Cartage – Local cargo haulage by drays or trucks (also called drayage).

Cartel Ship – Unarmed ship used for exchanging prisoners of war during hostilities. Also applied to an armed ship carrying emissaries for negotiating terms under a flag of truce.

Cartographer – Person employed in compiling or drawing charts.

Cartography – The drawing or compiling of charts. Map and chart making.

Carvel – Edge to edge planking that creates a smooth surface, unlike clinker construction. Short form of ‘caravel‘.

Carvel Built – System of building wooden craft in which the side planking goes fore and aft, with the longitudinal edges butting and flush.

Carvel Joint – Flush or butting joint.

Carving Note – Form filled in by owner of a ship under construction. States particulars of tonnage, construction, name, port of registry, etc. When signed by surveyor, becomes authority for relevant particulars to be ‘carved’ in main beam of vessel.

Case – Name given to inner planking of a diagonally-built boat, to differentiate it from the outer planking, or ‘skin’.

Case dogs/hooks – Pair of spiked clamps fitted to crates to facilitate lifting.

Casing – Short form of ‘Funnel casing’.

Cask – Barrel for containing either solids or liquids.

Cassini’s Projection – Used in British ordnance survey maps. Graticule is built in relation to a point in a central meridian.

Cassiopeia – Constellation on opposite side of North Pole to Ursa Major. In Greek mythology, was wife of Cepheus and mother of Andromeda.

Cast – To sheer a vessel in a desired direction. 2. To take a sounding with lead and line. 3. To throw. To begin.

Cast a Traverse – To reduce, arithmetically, a number of courses steered to a resultant distance and direction made good.

Cast Away – Said of a vessel that has been deliberately wrecked. Said of a man who has been shipwrecked.

Cast Off – To let go. To let go the lines that secure a vessel to a berth.

Casting – Turning a vessel’s head in a desired direction, before weighing anchor or slipping a buoy, by action of propeller, sail, rudder, wind or tide.

Casting Off – Letting go the ropes and hawsers that attach a vessel to a wharf quay, etc.

Castor – Star α Geminorum. S. H. A. 247°; Dec. N 32°; Mag. 1.6. When observed by a telescope is seen to consist of three pairs of twin stars. Castor and Pollox. Name given to two corposants when seen at the same time.

Casualty – Any accident to a ship or man that involves damage or death.

Casuarinas – Trees having no leaves but with short, ribbed sheaths. Observable in Indian Archipelago and Australia.

Cat – Purchase or rope by which an anchor is lifted to billboard after weighing. 2. Former sailing vessel having three masts, no beakhead, narrow stern, projecting quarters and high waist. Carried about 800 tons. (This may have been Dick Whittington’s ‘cat’).

Cat Back – Small rope attached to back of hook of cat purchase. Used for placing cat hook into ring, or balancing band, of anchor when anchor is awash.

Cat Block – Lower block of a cat purchase; carries the cat hook.

Cat Boat – Small boat with single gaff sail and mast set right forward.

Cat Davit – Strong davit for lifting anchor from water line to billboard when weighing anchor.

Cat Fall – Rope rove in a cat purchase.

Cat Harp- (ings) – (ins) – (ens) – Ropes bent to foremost shroud of futtock rigging to bowse it aft when sailing close hauled. 2. Name given to iron leg confining upper ends of standing rigging to mast. Ropes bowsing in the lower ends of the port futtock shrouds to the lower ends of the starboard futtock shrouds.

Cat Heads – Strong timbers projecting from either side of bows of olden ships. Fitted with sheaves for reeving cat purchase.

Cat Hook – Strong hook in end of cat pendant for lifting anchor to billboard when catting.

Cat o’nine tails – An instrument of punishment being a whip with nine strands as the terminal.

Cat Pendant – Wire rope rove through block on cat davit to lift anchor when catting it.

Cat Purchase – Tackle by which anchor is lifted from water level and placed on billboard.

Cat Rig – Rig with one or two masts, the foremast right forward and carrying no sail before it. Modern version: schooner or ketch rig with no head sails, with unstayed masts, wish-bone booms and wrap-round sails.

Cat Rope – ‘Cat Back.’

Cat Tackle – ‘Cat Purchase.’

Cat’s Paw – A hitch made in a rope. A light current of air on the surface of the water.

Catabatic – See ‘Katabatic’.

Catadioptric Lens – Arrangement of lenses so that a light is both reflected and refracted in a desired direction. Suggested by Alan Stevenson in 1834. Used in many lighthouses.

Catalyst – An agent that provokes a reaction.

Catamaran – A twin hull vessel.

Catch a Crab – To put blade of oar in water so that it is inclined from horizontal, and forward edge is lower than after edge. Way of boat causes blade to be pushed downward and aft, thus jamming it in rowlock.

Catch a Turn – Take a temporary turn with a rope.

Catch Ratline – Ratline of greater strength than the majority. Was placed at regular intervals, usually every fifth ratline.

Catching up Rope – Light rope secured to a buoy to hold vessel while stronger moorings are attached.

Catenary – Originally, length of chain put in middle of a tow rope to damp sudden stresses. Now applied to any weight put in a hawser for same purpose. 2. Curve formed by a chain hanging from two fixed points.

Catharpin Swifter – Foremost shroud of futtock rigging.

Cathead Stopper – Chain or rope that holds ring of anchor when stowed on billboard.

Cathode Protection – Sacrificial or impressed current system of corrosion protection used on vessels.

Cathode Ray Tube – A type of electronic valve with a screen which glows brightly where it is struck by a stream of electrons released when an echo is received. This type, used in a radar set, is known as a Plan Position Indicator.

Cathode – The nobler metal of an electrolytic cell. See anode.

Cathodic Protection – Hull protection against electrolytic action. Sacrificial anodes are fitted.

Catoptric – Name given to lights intensified by means of mirrors.

Cat’s Eye – ‘Cat Hole.’

Cat’s Skin – Light, warm wind on surface of sea.

Catspaw – Manipulation of a bight of rope so that two small loops are made for taking hook of a tackle. 2. Ripple made on calm water by a passing light air.

Catting – Lifting the flukes of a weighed anchor on to billboard or anchor bed. Hoisting the anchor from the water to the cathead.

Catting Link – Special link, with broad palm, used in catting anchor.

Catting Shackle – Special screw shackle used when catting anchor.

Cattle Carrier – Ship built to carry cattle.

Cattle Door – Large door in vicinity of bridge or ‘tween deck superstructure. Used when loading or discharging cattle on the hoof.

Cattlemen – Men carried to attend cattle when carried on the hoof.

Catug – A catamaran tug locked onto the stem of a barge, the center body of the tug riding on the stem of the barge.

Catwalk – A narrow and unfenced gangway.

Caulk – To make a joint watertight. 2. To press oakum, or other fibre, in a seam between planking preparatory to ‘paying’. 3. To expand the overlapping edge of a riveted iron or steel plate so that it prevents water seeping through the joint.

Caulker – One who caulks seams.

Caulking Iron – Tool used for pressing down caulking in a seam preparatory to paying.

Caulking Mallet – Wooden mallet used for applying force to caulking iron.

Causa Proxima – Latin for ‘Proximate Cause’.

Causeway – A raised pathway across swamp or water.

Caval (kevel) – A two armed metal deck fitting around which a vessel’s lines are made fast.

Cavitation – Reduction in propeller efficiency caused by air pulled down around its blades.

Cay – Sand or coral islet.

Ceiling – Wooden covering over tank tops in bottom of a hold. Formerly, was that portion of a ship’s side inboard and between deck beams and limber strake. This meaning is still retained in ‘spar ceiling’.

Celestial – Pertaining to the sky, or celestial concave.

Celestial Concave – The heavens. The celestial sphere.

Celestial Equator – Great circle of celestial sphere that is 90° from celestial poles. Is plane of Earth’s equator carried to celestial concave. Usually called the Equinoctial.

Celestial Horizon – ‘Rational horizon.’

Celestial Latitude – Angular distance above or below plane of Ecliptic. Measured on a circle of celestial longitude and prefixed with plus sign if north of Ecliptic, minus sign if south of it. Not usually considered in navigation.

Celestial Longitude – Angular distance along Ecliptic from First Point of Aries, measured in direction of Sun’s apparent path and expressed in arc 0° to 360°. Not usually considered in navigation.

Celestial Meridian – Great circle of celestial sphere that is a secondary circle to Equinoctial. Declination is measured on it.

Celestial Navigation – To position find by observing the stars.

Celestial Poles – Those points in celestial concave that are in the zenith at north and south poles of Earth.

Celestial Sphere – General name for the heavens, or sky. Heavenly bodies are assumed to be on the interior surface of a hollow sphere. Name is sometimes given to a globe showing places of stars on its outer surface. It is preferable to call this a ‘star globe’.

Cell – An anode and a cathode immersed in an electrolyte create a potential difference. This cell is a source of electrical current responsible for corrosion. The anode and cathode may be separate metals or dissimilar areas on the same metal. Also called an electrolytic cell.

Cellular Container Ship – A container vessel with vertical cell guides for standard sized containers limiting movement and lashing requirements.

Cellular System – Ship construction in which double bottom is divided into small spaces by erection of intercostal longitudinals between floors.

Celonavigation – Name suggested by Harbord (Glossary of Navigation) to denote navigational workings requiring observations of celestial bodies. Astronavigation.

Celox – Fast, single-banked vessel of Rhodes in classic times.

Celsius – (Centigrade) Graduation of thermometer scale in which the freezing temperature is 0°C and boiling point 100°C.

Celsius Temperature Scale – Temperature scale of 0º (freezing water) to 100º (boiling water).

Cement – Calcined chalk and clay in powder form. Mixed with water and an aggregate (sand, etc.). Is alkaline, so neutralising acids. Used in ships as protection against abrasion, corrosion, percussion, to give additional strength and for stopping leaks.

Cement Box – Portland cement and aggregate inserted between wooden shuttering and a leaking plate, or seam, to stop the leak.

Centaur (us) – Bright constellation in southern sky. Indicated by a line drawn through Arcturus and Spica. Has two navigational stars, α and β. Approx. R. A. 14 h; Dec. 60°S.

Centering Error – Sextant error due to centre of pivot not being at exact centre of arc. Error varies with altitude.

Centigrade Scale – Graduation of thermometer in which freezing point of water is 0° and boiling point is 100°. Is a modification of Celsius scale, and was introduced by Christin, of Lyons, in 1743.

Central Eclipse – Eclipse in which centres of the two heavenly bodies are exactly in line to an observer at a specified place.

Central Latitude – Angle at centre of Earth between plane of Equator and a line projected through observer. As Earth is not a true sphere this angle will differ from angle formed by downward projection of observer’s vertical—which is the ‘normal’ latitude.

Central Projection (of sphere) – Projection of surface of sphere to a tangent plane by lines from centre of sphere.

Central Sun – Point in the heavens about which the universe may be considered to turn. At one time was considered to be in constellation of Taurus.

Centre Board – Name often given to a ‘drop keel’.

Centre Castle – Raised part of a vessels hull amidships.

Centre of Buoyancy – That point in a floating body, at which the total moments of buoyancy in any one direction are balanced by equivalent moments of buoyancy in the opposite direction.

Centre of Cavity – ‘Centre of displacement.’

Centre of Displacement – That point, in a floating body, which is the geometrical centre of the immersed portion.

Centre of Effort – That point, in a sail, at which all wind force may be assumed to act. Theoretically, it would be the geometrical centre of sail area. In practice, it will be somewhat away from the theoretical point, due to sail not presenting a perfectly flat surface to wind, and not being at a uniform angle to wind in all parts.

Centre of Flotation – See ‘Centre of Displacement’.

Centre of Gravity – That point, in any body, at which the moments of gravitational force in any one direction are balanced by the moments of gravitational force in the opposite direction.

Centre of Gyration – That distance along a radius of a revolving body at which the mass may be considered to act. With disc of uniform density and thickness the centre of gyration is 0.707 of radius from centre of rotation.

Centre of Immersion – ‘Centre of displacement’.

Centre of Lateral Resistance – The geometrical centre of the side elevation of the underwater body of a sailing vessel. It is the point at which, in theory, the forces resisting leeway are considered to act. In practice this centre moves as the vessel heels and pitches.

Centre of Oscillation – That point, in a pendulum, at which total of moments of forces on upper side are equal to moments on lower side.

Centre of Percussion – That point, in a striking mass, at which the whole force of the blow would cause no jar. In case of a bar of uniform density, revolving around one end, would be 2/3 rds distant from centre of revolution.

Centre through Plate – Continuous girder going fore and aft along centre of bottom of a steel ship. Floors are attached to it on opposite sides.

Centreboard Case – A watertight box that houses the centreboard.

Centreboard – A plate that can be lowered to reduce a sailing boat’s tendency to make leeway when on the wind.

Centre-Castle – The raised part of a ship’s hull amidships.

Centrifugal Action – The process of dragging gas or liquids through the central inlet of a revolving turbine and flinging it out at its circumference at increased velocity.

Centrifugal Pump – Pump in which liquid is withdrawn by giving it a high rotational speed and allowing it to escape tangentially. Suction is provided by a partial vacuum caused by escaping liquid.

Cepheid Variables. ‘Cepheids’ – Particularly notable in constellation Cepheus.

Cepheids – Short period variable stars whose magnitudes vary in the course of a few days. Rigel, Canopus, Antares are examples.

Cepheus – Northern constellation situated between Cassiopeia and Andromeda. In Greek mythology, Cepheus was father of Andromeda and husband of Cassiopeia.

Ceres – First of the asteroids to be discovered.

Cers – A dry northerly wind of the Gulf of Lyon, southwest France.

Certificate of Clearance – Issued to master of emigrant ship, by emigration officer, when the latter is satisfied that ship is sea worthy, in safe trim, fit for intended voyage, that steerage passengers and crew are fit in health, that master’s bond has been fully executed.

Certificate of Competency – Certificate issued by Department of Transport to a seaman or officer who has passed an examination in a specified grade, and has been found fit to perform the duties of the grade. Certificate of Freeboard. International certificate, issued by an ‘Assigning Authority’, detailing minimum permissible freeboards in stated areas at specified seasons. Often called ‘Load Line Certificate’.

Certificate of Grain – ‘Grain Certificate.’

Certificate of Operation – A document specifying the operational conditions of an Australian domestic commercial vessel.

Certificate of Pratique – Certificate issued by medical officer of port to an arrived ship when he is satisfied that health of crew is satisfactory. Prerequisite to ‘Entry Inwards’.

Certificate of Proficiency in Survival Craft. Supersedes the old lifeboat certificate.

Certificate of Registry – A vessel’s identity certificate. A document that specifies the national registration of the vessel.

Certificate of Seaworthiness – Certificate granted by a surveyor, or Court of Survey, when the seaworthiness of the vessel may be open to question, and after she had been examined and found seaworthy.

Certificate of Survey – A document specifying the survey details of an Australian domestic commercial vessel.

Certificated Cook – Ship’s cook who holds a certificate granted by Department of Transport or an approved cookery school. Ships of 1000 tons gross and upward must carry a certificated cook.

Certificated Officer – Officer holding a certificate of Competency issued by the Department of Transport.

Cetaceans – Members of whale family, including dolphins and porpoises. They have warm blood and suckle their young. Some have vestiges of legs.

Cetology – The study of cetacea.

Cetus. (Lat. = Whale.) = Largest constellation in sky. Situated S of Aries. Has 97 discernible stars, two being of 2nd mag., eight of 3rd mag. and nine of 4th mag.

Chafe – To wear away through friction.

Chaffer – Said of a jib sail when it shivers in the wind.

Chafing Board – Piece of wood used to protect against chafing.

Chafing Cheeks – Wooden blocks without sheaves sometimes used in running rigging of lightly rigged, small sailing craft.

Chafing Gear – Paunch matting, sennit, strands, battens, etc., put on mast yard, standing rigging, etc., to protect against damage from chafe.

Chafing Mat – Any mat used as chafing gear, but particularly to paunch and thrum mats put on yards to protect them from chafe by backstays.

Chain – Name often given to chain cable.

Chain Boat – Boat used, in harbour, for recovering chain cable and anchors when slipped or parted.

Chain Bolt – Iron bolt used when fastening chain plates and ends of dead-eye chains to side of a wooden vessel.

Chain Cable – Anchor cable when made of wrought iron.

Chain Ferry – A ferry which proceeds by hauling itself along a chain laid across a river or channel.

Chain Gantline – Any gantline made of chain, particularly that rove through block at top of funnel.

Chain Hook – Iron hook with T handle, used when working cable. 2. Strong, two-pronged hook used for temporarily holding cable, inboard end being secured to deck, more usually called a ‘Devil’s Claw’.

Chain Knot – Succession of loops in rope, each loop being passed through previous loop.

Chain Lifter – Former name for sprocket ring of capstan.

Chain Locker – Cable locker. Locker for stowing anchor chain.

Chain Pipe – Strengthened hole in cable deck, and through which cable passes to locker.

Chain Plait – ‘Drummer’s Plait.’

Chain Plates – Plates on ship’s side to take lower ends of links or bars passing upwards to the chains. These plates take stress of shrouds, while chains give spread to the shrouds.

Chain Riveting – Paired rows of rivets spaced adjacently.

Chain Shot – Two cannon-balls joined by a length of chain and fired simultaneously. Used for destroying masts, spars and rigging. Invented by Admiral De Witt, 1666.

Chain Slings –. In general, any slings made of chain. Applied to the slings of a yard when made of chain instead of rope.

Chain Splice – Method of splicing rope to link of chain. One strand is unlaid and two strands passed through link; one of these two strands is laid up in space of strand taken out, and is half knotted to that strand. Other strand is tucked as usual.

Chain Stopper – Length of chain, about a fathom, used for holding a wire under stress while the wire is manipulated.

Chain Top – Additional sling (of chain) put on lower yards of warships before going into action.

Chain Towing – See ‘Chain Ferry’.

Chain Well – Former name for a chain locker.

Chains – Anchor chain. The extremity of the channels on sailing ship.

Chamfer – To take off the edge, or bevel the plank.

Chandler – A supplier of ships stores.

Change of Moon – Instant when centres of Sun and Moon are on same celestial meridian, and a new lunation commences.

Change of Trim – Alteration in the difference between the forward and after draughts of a floating ship.

Change the Mizzen – To brace the crossjack yard so that the mizzen course is on a tack different from the remaining sails.

Change Tide – Tide occurring at change of Moon, and, therefore, nearly a spring tide.

Channel – Narrow arm of sea between two land areas. 2. Deepest part of a body of water, and through which main current flows. 3. Longitudinal hollow or cavity. 4. Flat projection from side of a ship to give spread to rigging (usually called ‘chains’). 5. Standard rolled steel section in form of three sides of a rectangle.

Channel Bar – Rolled steel section having three sides of a rectangle.

Channel Bolt – Long bolt that passes through chains, or channels and side planking of a wooden ship; so clamping the chains to the side.

Channel Money – Advance payment of money due to a seaman 48 hours before being paid off. Was £2, or one-quarter of wages due, whichever is the lesser.

Channel Pilot – Pilot engaged in conducting ships in English Channel, or other specified channel. 2. A book of sailing directions for navigation of the English Channel.

Channel Plates – ‘Chain Plates.’

Channel Wale – That strake of side planking, of wooden ship, that carries a chain plate.

Chanty – Chanties. Nautical song of merchant seamen. Used to co-ordinate effort when hauling on a rope, or heaving at capstan or windlass.

Chapelliog – Putting a close-hauled vessel’s head through the wind without bracing head yards. May be deliberate, or through negligence of helmsman. Word is sometimes applied to wearing in same circumstances, but this is a later application of the word.

Characteristic – Of a logarithm, is the whole number of the Log, as distinguished from its mantissa. 2. Of a navigational light, is its colour, phase and period. Charges Cause. Inserted in Charter Party to denote who shall pay harbour and dock dues, wharfage, pilotage, towage, etc.

Charles’s Law States that volume of a gas, at constant pressure and at temperature 0°C increases by 3rd for each degree rise in temperature.

Charles’s Wain – ‘Churl’s wain,’ or ‘waggon’. Old name for ‘Ursa Major’.

Charley Moore – The embodiment of fair dealing. (R. N.)

Charley Noble – R. N. nickname for a galley funnel.

Charley noble: A galley’s stove pipe.

Chart – Representation of part of ocean or sea for use in navigation. Gives depth of water, nature of bottom, configuration and characteristics of coast, with positions and brief particulars of navigational aids. An image of geographical place that shows positions and navigational features.

Chart Abbreviations – Standardised abbreviations used in charts. The more important are generally shown under chart title, but all those used in British Admiralty charts are given on a special chart.

Chart Border – Graduated lines, at border of chart, for determining latitude and longitude of a position, and for measuring distances.

Chart Compass – Compass rose engraved on chart, to determine courses and bearings. Usually had an outer graduation 0°-360°, and inner graduation in quadrantal form. Inner compass gave variation, for given epoch, and the secular change. On modern charts both graduations are 0°-360°.

Chart Datum – Sea level used in connection with soundings on a chart. In British charts, is a level below which the tide very rarely falls. The level below which soundings are given and above which drying heights are given on charts.

Chart Distortion – Differentiated into distortion in and distortion of charts. Distortion in a chart is an unavoidable extension of charted area due to impossibility of accurately reproducing a spherical surface on a plane surface. It is adjusted by extending the units of measurement, latitude or longitude, to correspond with the extension of the area. Distortion of a chart is a possible stretching or contraction that may occur after printing, and so cause a slight relative displacement of a charted positions. In modern charts this distortion is rarely enough to affect navigation, but if the chart be large it may affect very precise surveying.

Chart House or Room – A compartment adjacent to the bridge for charts and navigation.

Chart Plate – Plate, usually of zinc or copper, on which a chart is engraved for printing. The exact size of this plate is given, in inches, in border of chart. This allows for checking the chart for distortion.

Charter Party – A contract between ship owner and a cargo owner, usually arranged by a broker, here a ship is chartered either for a voyage or a period of time.

Charter – To hire a ship.

Charterer – One who enters into a contract with a shipowner for the hire of a vessel, or for the carriage of goods by sea.

Charybdis – Name of one of the whirlpools, or garofali, in Straits of Messina.

Chasm – A deep fissure in the earth’s surface.

Chasse Marees – Bluff-bowed French luggers formerly used for fishing, and in short voyage trades. Had up to three masts and often carried topsails.

Chatham Chest – Fund for support of disabled and superannuated seamen of R. N. Founded in reign of Queen Elizabeth, on a voluntary basis which, later, became compulsory. Abolished during reign of William IV.

Check – To ease a rope a little, and then belay it.

Check Stopper – Length of small chain with one end made fast to a ring bolt, or other annular opening, then around a wire and back through the ring bolt. By hauling on free end of chain the speed of a moving wire can be checked and regulated.

Check Valve – A one way valve.

Checking – Slacking a rope smartly, carefully and in small amounts.

Cheek Block – Sheave on side of a spar, etc., and having a half shell on outer side.

Cheeks – Brackets below head of mast and at sides of it. Support crosstrees and mast above. 2. Knee pieces either side of stem. 3. Sides of a wooden (pulley) block. 4. Old name for a Royal Marine.

Cheeks Plates – The sides of a block that retain the pulley sheaves.

‘Cheerily’ – Injunction to perform an action smartly and with a will.

Cheese Cutter – Form of drop keel for small craft. Has a projecting upper part that is supported in housing when keel is down. 2. A peak cap. Cheesing down. Coiling a rope ornamentally with each flake flat, or almost flat, on deck; usually in a circular or figure-of-eight pattern.

Cheese – A bundle of spun yarn. To spread out a rope or twine. Chemical added to polyester/epoxy resins to assist curing.

Chemical Carrier – A vessel purpose built to carry of volatile, poisonous or corrosive liquids.

Chequered – Said of a flag or pendant made up of small squares of two different colours; and of a buoy or beacon painted in squares of two different colours.

Chernikeef Log – Submerged log that projects through bottom of ship. Carries an ‘impeller’ that turns as vessel moves through the water. Directly records distance run and, with electrical attachment, can indicate speed.

Cherub Log – Towed log consisting of a towed rotator, non-kinkable log line and an inboard registering unit. Measures distance directly.

Chess Tree – Oak block secured to ship’s side abaft fore chains. Used for boarding main tack, or as lead for fore sheet.

Chest Rope – Long boat rope led from forward to a gangway into ship.

Chetwynd Compass – Liquid type compass for use in quick-turning craft. Drag of liquid on rim of card was reduced by making card much smaller than containing bowl.

Chevils – Small pieces of timber, inside a ship, to which tacks and sheets can be secured.

Chief Buffer – Nickname for a chief boatswain’s mate in R. N. He is senior chief petty officer of upper deck, and so acts as buffer between the hands and the Commander.

Chief Mate The deck officer second in command of a ship. He assumes the position of the Master in his absence.

Chief or Chief Engineer – The senior engineer officer responsible for the satisfactory working and upkeep of the main and auxiliary machinery aboard ship.

Child Fender – Roller fender for wharf or quay. Consists of a central shaft, free to rotate, around which are large diameter rubber tyres filled with cork.

Chimes – Intersection of the lines forming sides and bottom of a flat-bottomed boat. ‘Chine.’

Chinagraph – A greasy pencil.

Chinckle –. Small bight in a rope or line. Often called ‘half crown’.

Chine – Former name for chime of a cask. 2. Gap in landward side of a cliff. 3. ‘Chimes.’

Chine log: Longitudinal member used to reinforce the join of sides and bottom of flat or V-bottom hulls.

Chine: The join between the bilge and topsides of a hull. Double chine – Having an additional planking junction between the chine and the sheer, giving the hull a more rounded look. Hard chine- Having a distinct bottom/side planking junction as opposed to a rounded curve. Multi-chine – Having one or more additional planking junctions between the chine and the sheer.

Chinese Windlass – Machine, by which purchase is gained by heaving one part of a rope, on a drum, and veering the other part on a drum of smaller diameter— a block being in bight of rope between the two drums. This principle is adopted in the ‘differential’ block.

Chinook – A dry snow melting katabatic wind of the American Pacific North.

Chinse – To fill a seam or crack by inserting oakum.

Chinsing Iron – Steel or wrought iron tool used for inserting oakum in a seam in planking, etc. Has a curved lower edge scored with a groove. Upper extension of handle has a wide, circular, convex head for applying power with a mallet.

Chip Log – Quadrantal piece of flat wood, weighted on curved rim, attached to log line for finding speed of a vessel. Often called ‘ship’ log, or log ‘ship’.

Chippy Chap – Nickname for ship’s carpenter, or one of his crew.

Chips – Nickname for a ship’s carpenter.

Chock – A fitting through which anchor or mooring lines are led. Usually U-shaped to reduce chafe.

ChockaBlock – Said of a purchase when two blocks are close together, and further hauling is impossible. Also called ‘Two blocks’.

Chock Boat – A support for a lifeboat.

Chocks – Wedges used to secure anything with, or to rest upon. A fillet of wood used to make good a deficiency in a plank.

Choke a Luff – To prevent a tackle walking back by passing a bight of the fall between a sheave and the rope rove through it, and on that side of sheave where rope would go into block if walking back.

Choke – A mechanism to provide richer mix while starting a petrol engine. An electrical coil to block out radio interference (noise).

Choked – The tackle falls jammed within a block.

Cholera – Infectious disease of Eastern origin. Marked by diarrhoea, cramp, vomiting and drying of tissues.

Chop Mark – Merchant’s mark on goods. Indicates grade and other particulars.

Chops of the Channel – Sea area immediately to westward of English Channel. First known use of this name was in 1748.

Chord – A straight line between the luff and leech of a sail.

Chosen Position – A chosen Lat. and Long. Within ½ degree of a vessels position to facilitate a celestial navigational fix.

Chromatic Aberration – Deviation of light rays after passing through curved lens. Results in coloured fringes around observed objects, caused by unequal refraction of lenses breaking up light into its constituent colours.

Chromosphere – Incandescent gaseous envelope surrounding Sun.

Chronograph – A chronometer combined with a recording drum and a pen.

Chronometer – Very accurately constructed timepiece with a balance wheel of a form that precludes error through change of temperature. Balance wheel is affected by mainspring for only a very small period of its oscillation. Invented by John Harrison about 1728.

Chronometer Journal – Book for recording comparisons of chronometers carried in a ship. Shows their error on time signal, and on each other. Daily rates, also, are deduced and entered.

Chronometer Watch – Small timepiece made on chronometer principle and used for taking times on deck. See ‘Deck Watch’.

Chronometric Difference – Difference of longitude between two places when expressed as the difference of their local mean times.

Chuch. Name sometimes given to a fairlead.

Chutes – Inclined troughs, down which coal, ashes and fluid substances can slide. 2. Vertical canvas tubes used for ventilating. Often spelt ‘shoots’.

Circle – Plane figure bounded by a line that, at all points, is equidistant from a point termed the ‘centre’. Can be considered as the section of a sphere by a plane. Word is frequently applied to its circumference, as in ‘position circle’.

Circle of Altitude – Great circle of celestial sphere, secondary to horizon, on which altitudes are measured.

Circle of Azimuth –Great circle of celestial sphere passing through zenith; so passing through all points having the same azimuth.

Circle of Curvature – Circle whose curvature is the same as that of a curve under consideration.

Circle of Declination – Great circle of celestial sphere that is perpendicular to Equinoctial. So called because declination is measured along it. Not to be confused with ‘Parallel of Declination’.

Circle of Equal Altitude – Circle, on surface of Earth, passing through all positions at which the body has the same altitude. It is a great circle when body is in horizon, decreasing to a point when body is in the zenith.

Circle of Excursion – Small circle, parallel to Ecliptic, marking the maximum celestial latitude of a planetary body.

Circle of Illumination – Great circle, on surface of Earth, that divides day from night.

Circle of Latitude – Alternative name for a circle of celestial longitude. So named because latitude is measured on it.

Circle of Longitude – Great circle of celestial sphere, secondary to Ecliptic, passing through all points having the same celestial longitude.

Circle of Perpetual Apparition – Parallel of declination, above which all the diurnal circles are entirely above horizon.

Circle of Perpetual Occultation – Parallel of declination, below which all the diurnal circles are entirely below horizon.

Circle of Position – Small circle on surface of Earth, and on the circumference of which an observation shows observer to be.

Circle of Right Ascension – Great circle of celestial sphere, passing through all points having the same right ascension.

Circle of Sphere – Formed by intersection of a sphere by a plane. May be ‘great circles’ or ‘small circles’, depending on whether the plane does, or does not, pass through centre of sphere.

Circle of Tangency – ‘Tangent Circle’.

Circlip – A sprung split ring that fits onto a groove of a shaft and thus retains other shaft fittings from falling off the otherwise open end.

Circuit – Series of connected conductors that form a path for an electric current.

Circuit Breakers – A safety device used in electrical systems to cut the supply of electricity when a fault is evident.

Circular Note – Letter of credit addressed to financial firms in other countries. Authorises them to make payment to person named.

Circular Parts – ‘Napier’s Circular Parts.’

Circular Sailing – Former name for ‘Great circle sailing’.

Circular Storm – Former name for a cyclonic storm.

Circulating Pump – Centrifugal, or double-acting pump, that draws water from sea and delivers it at external surfaces of condenser tubes, so condensing exhaust steam from engines.

Circulation – Process by which water in a boiler is moved so that the whole mass is of uniform temperature. Partly done by convection, but hastened by pump and special fittings.

Circummeridian – About or near the meridian.

Circumnavigate – To sail completely around. Sometimes especially applied to sailing around Earth.

Circumnavigator’s Day – The day ‘lost’ or ‘gained’ by the navigator when date is altered on crossing the Date Line on W’ly or E’ly course (respectively).

Circumpolar – Term applied to a heavenly body that makes a diurnal revolution around pole of heavens without passing below horizon.

Cirrocumulus – A high form of cloud often called ‘Mackerel sky’. Formed by small, rounded masses of cloud.

Cirrostratus – High, tenuous cloud of uniform density. Often precedes a depression.

Cirrus – Feathery, fibrous, detached clouds, white in colour, that are formed by ice crystals at heights of five to seven miles. They are the highest, feathery, ice clouds.

Cirrus Nothus – ‘False Cirrus.’

Cistern – The mercury container of a barometer. Pressure of atmosphere in cistern forces mercury up the glass tube that has been exhausted of air.

Civil Day – Period from midnight to midnight in the mean time standard at a given place.

Civil Twilight – Interval between Sun’s upper limb being in horizon, and his centre being 6° below it.

Civil Year – The year in common use. Is the Tropical year adapted for civil purposes. Has 365 days for three years and 366 in fourth with slight adjustment at ends of centuries.

Clack Valve – Hinged valve that opens by suction and closes by gravity.

Clamp – Strong plank supporting deck beams at ship’s side. 2. Cleat, on after end of a boom, to take reef pendants. 3. Half round, hinged fitting for securing heads of derrick booms, etc. etc.

Clamp Nails – Strong nails with large, round head. Used for fastening clamps to sides of wooden vessels.

Clap On –To apply extra power, either by increasing purchases used, or by putting on additional men. 2. To set more sail.

Clapper – Tongue of a bell. 2. Chafing piece in jaws of a gaff.

Clark Russell’s Log – Early type of towed log in which speed of ship was indicated by amount of compression in a spring.

Clarke’s Figure of Earth – Measurement of Earth’s polar and equatorial diameters and factors of compression made by Clarke in 1858-66-80. Equatorial diameter 20, 926, 348 ft., polar diameter 20, 855, 233 ft., compression 1/294.3. These values are still used in many modern charts.

Clasp Hook – Former name for ‘Clip hook’.

Classification of Stars – Astronomers group stars according to spectra and temperature. Seven principal groups are 0, B, A, F, K, G, M. The temperature of 0 stars is about 50, 000°C. M stars do not exceed 3000°C. This classification is not usually considered by seamen, but is to be found in the

Classification Societies – Organisations established for the purpose of obtaining an accurate classification of merchant shipping, for maintaining a standard of seaworthiness and safety, and for making the obtained information available for shipowners, merchants, underwriters and others concerned. The principal are Lloyd’s Register of Shipping (founded 1760) and an international Bureau Veritas. They are, also, ‘assigning Authorities’ for granting Load Line Certificates under the ‘Safety and Load Lines Conventions Act, 1932.’

Claw Of – To beat to windward of a lee shore or danger.

Cleading – Any covering used to protect or to prevent the radiation or conduction of heat.

Clean – Said of a Bill of Lading, or other document or receipt, when it contains no restrictive endorsement. Ship is said to be clean when her Bill of Health is satisfactory. Said of a ship’s underwater surface when it is free from weed or other fouling.

Clean Lines – Said of a vessel having fine entrance and lines.

Clean Ships – Tankers whose cargo tanks are free of traces of impurities that remain after carrying crude or heavy fuel oils.

Clear a Lunar – To deduce Moon’s true distance, from a heavenly body, from her apparent distance. Short form of ‘Clearing a Lunar Distance’.

Clear a Ship – To enter a vessel ‘Inwards’ or ‘Outwards’ at Custom House.

Clear Anchor – Said of a weighed anchor when it comes in sight and is seen to be clear of turns of cable.

Clear Away – To remove restraints from gear in preparation to anchor.

Clear Berth – The circle that is available for a ship to swing clear of obstructions within its anchorage. Opposite of foul berth.

Clear for Action – To remove all obstacles and unnecessary fittings in way of a gun, or in path of its projectile, and all furnishing that may hinder the fighting of the ship, or are liable to cause fire.

Clear for Running – Said of ropes coiled down so that the end of rope is underneath, and rope can run freely and uninterruptedly.

Clear Hawse – Said of cables when each leads clear to its anchor, and there is no cross or turn in them.

Clear Hawse Slip – Special slip, on cable deck, for holding inboard end of foul cable while clearing it of turns.

Clear the Land – To attain such distance from the coast as to be out of danger from outlying obstructions and shoals, and from risk of being carried on to them by currents or wind.

Clearance – Act of clearing a vessel through a Customs House by the fulfilment of required duties. 2. Certificates given by Customs authorities when a vessel has been satisfactorily cleared. 3. The amount of free space between two nearly adjacent surfaces or points.

Clearance Inward – Customs procedure of an arrived vessel. Jerquing Note is delivered to master when cargo has been discharged and Customs authorities are satisfied that all requirements have been met.

Clearance Label – ‘Cocket Card.’ Attached to a Victualling Bill and stamped by Customs authorities as evidence that all requirements have been satisfactorily met by an outward bound vessel.

Clearance Outwards – The obtaining of a Victualling Bill and clearance by the master of an outward bound ship. The issue of these is an official permission to sail.

Clearer – Tool on which hemp for sailmaker’s twine is finished.

Clearing Bearing – Clearing line that is projected through one particular bearing only.

Clearing Line – Straight line, on chart, that marks boundary between a safe and a dangerous area; or that passes clear of a navigational danger. Sectors of lighthouse lights are usually bounded by them.

Clearing Marks – Natural or constructed navigational marks in transit that when sighted open of each other mark a track clear of dangers.

Clearing the Distance – Converting the observed angular distance of a star from Moon to its true angular distance.

Cleat – Metal or wood fitting having two projecting horns and fastened securely at the middle. Used for securing or controlling ropes.

Cleating – Tying a rope to a cleat.

Clench – To bend over the internal end of a copper nail after it has been driven through the plank, thus increasing its holding power.

Clench Bolt – Bolt whose end is beaten out over a washer after passing through the items it clenches.

Clench Built – ‘Clinker built.’

Clench Nail – Nail whose tapered end is beaten out, over a roove, after being passed through the items it fastens.

Clenched – Old form of Clinched’.

Clencher – ‘Clincher.’

Clevis Pin – A headed rod with holed end to accept a split pin, used as a shackle bolt or similar.

Clew – Lower comer of a square sail, lower after comer of fore and aft sail. Has thimble for taking sheet and other tackle.

Clew Garnet – Tackle attached to clew of a course for hauling clew to yard when furling.

Clew to Earing – Said of a sail when clew has been hoisted to earing by clewline or clew garnet.

Clew Up – To haul clew to earing when furling a square sail.

Clewline – Rope for hauling up clew of an upper square sail when furling.

Clew-outhaul – A tackle to stretch the foot of a sail along the boom.

Climate – The mean of weather conditions.

Climatic Zones – Eight zones of climate into which Earth’s surface can be divided. They comprise one of Tropical Rain; two of Steppe and Desert; two of Temperate Rain; in Northern hemisphere; one Boreal, with large annual range of temperature; two Polar caps of snow.

Clinch – To fasten two overlapping strakes by a fastening through the overlap. 2. Half hitch stopped to its own part. 3. To chinse. 4. Old name for attachment of inboard end of rope cable to ship.

Clincher Build – Method of building wooden craft so that each strake of side planking overlaps strake below it, and is clinched to it along the doubling.

Clinching Iron – Tool used when clinching nail over a washer.

Clinker – Fused ash, and other incombustible substances, that form when coal is burned in a furnace.

Clinker Pieces – Small doubling patches at peak and clew of gaff sails.

Clinometer – Instrument used for measuring the heel or inclination of a vessel.

Clip – Jaw end of a boom or gaff. 2. Inglefield clip.

Clip Hooks – Two flat hooks, on one ring or thimble, that hook in opposite directions and overlap.

Clipper – A fast, highly canvassed, fully rigged ship.

Clipper Bow – Name applied to a bow in which stem curves forward as it rises above waterline. Also called a Schooner Bow.

Clipper Built – Said of a sailing vessel having fine lines and raked masts.

Clock Calm – Absolutely calm weather with a perfectly smooth sea.

Clock Stars – Stars whose right ascensions and declinations are very accurately known, so that they can be used for determining time. (Astronomers do not use Sun for this purpose.)

Close – To approach.

Close Aboard – Close alongside. Very near.

Close Butt – Joint, in wooden shipbuilding, that is so close that caulking is not necessary.

Close Fights – Barriers and obstructions erected to prevent capture of ship by boarding. In some cases, but not in R. N., were strong bulkheads erected on upper deck, behind which ship’s company could retreat when boarded; so commanding upper deck with musket fire through loopholes in the bulkhead.

Close Harbour – Old name for a harbour made by engineering skill and excavation; to distinguish it from a natural harbour.

Close Hauled – Said of a sailing vessel when she has the wind before the beam. In some cases is applied to a vessel sailing as close to wind as possible.

Close Jammed – So close hauled that any movement nearer the wind would put sails aback.

Close Lined – Said of a vessel when ceiling on sides of hold is so close that there is no air space between the planks.

Close Pack – Mass of ice-floes, mostly in contact, that impede or stop navigation.

Close Quarters – In close proximity. Yard arm to yard arm. 2. Close fights. 3. Close fights fitted in slave ships to prevent uprising of slaves.

Close Reefed – Said of sails that have been reefed as much as possible.

Close Stowing Anchor – Any anchor having its stock in line with arms.

Close the Land – To approach the land from seaward.

Close Winded – Said of any vessel that can sail close to wind.

Closed Stokehold – Stokehold that can be made airtight, and so allow air pressure to be increased for more efficient combustion of fuel.

Closed Traverse – See ‘Traverse’.

Cloth – Piece of canvas forming part of a sail.

Clothe – To fit a vessel with her running rigging and sails.

Clothed – Said of a mast when all sail is set on it. Sometimes used as meaning that the foot of a lower sail is so close to deck that no wind can pass beneath it.

Cloud – Water vapour condensed  into minute particles and suspended in higher reaches of atmosphere.

Cloud Cover – The proportion of the sky covered by visible cloud measured in units of Octas, from one (minimal cover) to eight (full cover).

Cloudburst – Name often given to very heavy rain.

Clove Hitch – Manipulation of rope end for attaching it to a bar, taut wire, etc. End is passed round, then over its own part, then round again—in same direction—and brought up under its own part.

Club – Spar at foot of jib, or other triangular sail. 2. Group of shipowners forming a mutual insurance society. See ‘Small Damage Club’.

Club Hauling – Method of putting a sailing vessel about when on a lee shore and there is no room to tack or box haul. Necessitates use of, and loss of, an anchor, a length of cable and a spring from lee quarter to anchor. As vessel comes head to wind, and loses way, anchor is let go, yards are braced to new tack and cable is slipped. Spring is slipped as soon as after sails are filled.

Clubbing – Dropping down with tide or current, with anchor at short stay, and sheering vessel as necessary with rudder. Usually termed ‘dredging’.

Clump Block – Thick wooden block built to take a rope whose circumference is half the length of the block.

Clump Cathead – Small projection from ship’s side just abaft hawse pipe. Used for suspending an anchor when cable is disconnected and used for mooring to a buoy.

Clutch – A mechanism to couple or uncouple a drive shaft from its engine.

Clutter – Confused, unwanted echoes on a radar display from, e. g. waves or rain.

Clyde Lug – Standing lug with high peak, mast stepped well forward, sheet travelling on a horse mounted on transom.

Clyde Puffer – River and coastwise steam barge about 100 tons. Exhaust to atmosphere without a condenser, hence the puff.

Co – Prefix meaning ‘Complement of’.

CO2  – Symbol for ‘Carbon dioxide’ or carbonic acid gas.

Coach Whipping – Covering made by small line and used for ornamental purposes, or as a protection against chafing. Three or four lengths are passed over and under other lengths, of the same number, so that a close diaper pattern is made.


Coadherent – Old name for a bilge keel.

Coak – Bush of a sheave.

Coaking – Joining timbers by scarphing, in which one timber has a projection and the other timber has a recess into which the projection is fitted.

Coal Bunker – Compartment in which coal for ship’s consumption is kept.

Coal Consumption – Amount of coal, in tons, consumed in a given time, for a given distance, or for a time given speed in knots. Consumption in a given time varies as cube of speed; consumption per knot varies as square of speed; consumption over any distance varies as square of speed x distance. All the above are approximate.

‘Coal Sack’ Area in the Galactic (Milky Way), and in vicinity of α Centauri, where no star whatever is visible to the naked eye. The area is about 8° in length and 5° in breadth.

Coaling Stations – Ports and places where coal suitable for marine boilers may be had by ships.

Coamings – Vertical erections around hatches, and other openings in a deck, to prevent water from entering to the opening.

Coarse Acquisition – the radio signal on the L band frequency of 1575.42 MHz that civilian GPS receivers use. As opposed to the P code used by the US military.

Coast – That part of any country or land that is washed by the sea. 2. To sail along a coast, or to follow the coastline.

Coast Earth Station (C.E.S.) – Maritime name for an Inmarsat shore-based station linking ship earth stations with terrestrial communications networks.

Coastal Plain – Low lying land along the edge of the coastline.

Coastal Radio – Radio traffic in inshore waters

Coastal Waters – Sea area along the edge of the coastline.

Coaster – Vessel trading along the coast of a country.

Coastguard – Force of men, who were stationed around coasts for the suppression of smuggling and for watching of coast for vessels in distress.

Coasting – Navigating form headland to headland.

Coastline – That line in which sea meets the border of a country; more specifically at low water.

Coat – A piece of canvas, tarred or painted, placed around mast or bowsprit where it enters the deck, to keep out water.

Coaxial Cable – An insulated conducting cable surrounded by an insulated conducting sleeve used for connecting an aerial to its transceiver.

Cob – Stone breakwater protecting a harbour.

Cobalt – Hard, white metal used in high carbon steels for permanent magnets. Is feebly magnetic.

Cobbing – Old maritime punishment in which a man was struck on the breech with flat pieces of wood or ropes’ ends.

Cobble – Original form of ‘Coble’.

Coble – Boat with flat floor, square stern and deep rudder. About 20 feet long. Pulls three pairs of oars and has a mast with lugsail. Once in daily use on North-East Coast.

Coboose – Old form of ‘Caboose’.

Cochrane Boiler – Small vertical boiler sometimes installed in ships for port use. Has combustion chamber and smoke tubes. Working pressure is about 120 Ib. per sq. in.

Cock – Valve in which flow of a fluid is controlled by a rotatable plug which has a perforation that can be masked by turning. 2. Old name for a yawl. 3. Old name for a ‘Cog’ (boat).

Cock Boat – Small, light boat used in sheltered waters.

Cock-a-Bill – An anchor hanging by the ship’s side.

CockbiII – To top a yard by one lift. 2. To suspend an anchor by ring stopper.

Cocked Hat – Former full dress headgear of an officer of the R. N. 2. Triangle, on chart, formed by three position lines that do not cross at one point.

Cocket – Seal of H. M. Customs. Name is given, also, to ‘Clearance Label’, and to an Entry officer in a Custom House.

Cocket Card – ‘Clearance Label.’

Cockpit – A deck area that is lower than the sheer line of the boat and exposed to the elements.

Cockscombing – Decorative covering of a small spar or rope. Made by attaching several small lines and half hitching them, successively, around object to be covered. Number of lines used should be odd. Half hitches are made to right and left alternately.

Cockswain – Original form of ‘Coxswain’.

Cod Line – Small line made of Italian hemp, and supplied in hanks of 20 fathoms. Originally, was a fishing line, with a size between mackerel and dolphin lines.

Cod of Track – Most westerly point in track of a revolving storm. Storm centre turns toward pole, and then eastward.

Code Flags (Letters) – Alphabet of flag signals for speaking at sea, as included at each letter heading in this dictionary.

Cod’s Head and Mackerel Tail – Nickname given to ships built with bluff bows and a long and tapering run.

Coefficient – Numerical constant used as a multiplier of a varying quantity.

Coefficient of Fineness – Decimal fraction by which the volume of a rectangular block must be multiplied to obtain displacement of a floating vessel whose underwater body has the same maximum length, breadth and depth. Also known as ‘Block coefficient’.

Coefficient of Waterplane Area – Area of waterplane, at a given draught, expressed as a fraction of the area of a circumscribing rectangle. Value, for ship shaped bodies, usually varies between 0.7 and 0.85.

Coefficients of Form – Used to describe the shape of the ship’s hull when comparing one with another. The coefficients are used in power, stability, strength and design calculations.

Cofferdam – Space between two bulkheads, or walls, that receives and retains any liquid that has leaked through one wall.

Coffin Plate – An inverted boss plate.

Coffin Ships – Vessels unseaworthy through defect in building, fitting or loading. Were unduly prevalent before legislation enforced loading limits and other safety measures.

Coffin Stern – Name given to stern plating that is vertical, flat and V-shaped.

Cog – The dominant type of vessel of the period 1200 to 1400. Flat bottomed, clinker built at first, but later carvel built, high sides, straight sloping stem and stem posts with stem rudder. Single mast and square sail.

Coggle – Old name for a small cog, or boat.

Coil – Quantity of rope when made up in circular form. Length may be 113 or 120 fathoms, more or less, according to type. To coil a rope is to lay it in coil.

Coil – To lay a rope up in a circle, with one turn or fake over another. A coil is a quantity of rope laid up in this manner.

Coiling & Pinkney’s Topsail – Was carried on a rolling spar on fore side of topsail yard. Could be furled, or reduced in area, by ropes working on principle of a roller blind.

Coir – Fibrous outer covering of the coconut.

Coir Hawser – Hawser made of coir fibre. About two-thirds the weight and onequarter the strength of hemp hawser of same size. As it floats on water it is useful for warping.

Col –Saddle-shaped area between two anticyclones and two depressions when they are arranged so that a line joining the two depressions crosses a line joining the two anticyclones. Through this area there is an air-flow from anticyclones to depressions.

Col – Meteorological term for area between high and low pressure systems.

Co-latitude – Complement of any given latitude. Value of intercepted arc of a meridian between elevated pole and observer’s zenith.

Cold Front – The boundary where a parcel of cold dense polar air (advancing towards the equator) drives underneath the warmer air ahead.

Cold Sector – That part of a depression in which cold air is in contact with surface of Earth. Varies from 75 % to total according to age of depression.

Cold Wall – Longitudinal area of cold air. 2. Line of demarcation separating the Gulf Stream from the Labrador current.

Cold Wave – Fall of temperature that follows the passing of cold front of a depression.

Collapsible Boat – Boat with wood or metal framing and fabric skin, so arranged that boat can be folded up for close stowage.

Collar – A ring of plate positioned around a pipe or mast at a bulkhead or deck opening that serves to provide a sealing reinforcement.

Collar Beam – Beam on which stanchions of beak head bulkhead rested.

Collar Knot – ‘Granny’ knot in middle parts of two ropes that are to make two pairs of shrouds when jury rigging. Knot is opened out and dropped over mast head.

Collet – A split circular inset that tightens on a shaft when longitudinal compression is applied, used in winch clutch or drill chuck applications.

Collier – Vessel specially fitted for carrying coal.

Collimation – Correct alignment of the optical parts of an instrument.

Collimation Error – Of a sextant, is an error due to optical axis of telescope not being parallel to plane of sextant arc.

Collin’s Rule – For determining the positive buoyancy of a cask or barrel in Ibs. Usually expressed as 5C2 L—W; C being mean circumference, L being distance between headings and along curve; W being weight in Ibs. All dimensions in feet.

Collision – The striking together of two bodies in motion. Sometimes used to denote a moving vessel striking a stationary object. In the ‘Memorandum’ of a marine insurance policy it is limited to collision with another vessel, but not with permanently stationary objects. Does not include striking pier heads, wharves, piers, derelicts, floating wreckage, trawl net or a wreck that could not be salved. Does include collision with light-vessel, anchor cable, or a wreck that could be salved.

Collision Bulkhead – Unpierced bulkhead extending to upper deck. Placed about 0.05 of vessel’s length from stem. Limits entry of sea in event of head-on collision.

Collision Clause – ‘Running Down Clause.’

Collision Mat – Thrum mat, about 10-12-ft. square, which can be hauled under ship’s bottom to cover collision damage resulting in a leak. Kept in place by lowering line, bottom line and two fore and aft ropes.

Collision Regulations – An IMO Convention, The International Regulations for Preventing Collisions at Sea.

Colour Blindness – Inability to distinguish between different colours, through defective eyesight.

Colours –  Identity of a vessel (as shown by flying the national flag).

Colt – Knotted rope’s end used for minor punishment.

Columba (Noachi) – (Noah’s) Dove – Constellation SW of Canis Major. Has one navigational star, Phact. S. H. A. 275°; Dec. S34°; Mag. 2.8.

Column – Line of two or more ships sailing in formation. 2. A derrick post.

Colure – Great circle passing through poles of Equinoctial. Generally restricted to the great circles passing through Equinoctial and Solstitial points.

Comb – Small piece of timber for carrying fore tack block. Was usually under lower part of beak head.

Comb Cleat – Small fitting having holes through which ropes may be rove to prevent fouling of one rope by another.

Combers – Step long swell with high and breaking crests.

Combi – Combination passenger/cargo vessel specifically designed for containers and conventional cargoes.

Combined Altitude – Two altitudes of one heavenly body, or altitudes of two different bodies, when taken to solve one problem.

Combings – ‘Coamings.’

Combustion – Burning, the act of burning, the state of being burnt. Is a chemical action accompanied by heat and, usually, by light.

Come Home – Sometimes said of an anchor when it drags along bottom. More correctly said of an anchor when it comes towards ship when heaving on cable, instead of ship moving towards anchor.

Come To – Injunction, to helmsman of sailing ship, to come nearer to wind.

Come to Anchor – To drop an anchor and ride by it.

Come Up – Order to those hauling on a rope to cease hauling and light the rope in opposite direction, so that it can be belayed.

Coming up Tack – That tack on which a sailing vessel rides out a cyclonic storm. Is the tack on which she will be brought to windward of her course by changes in wind direction.

Commander – Naval officer next in rank below Captain. Master of a Merchant Navy vessel. 2. Large wooden mallet used in rigging work.

Commanding Officer – Of a ship, is the senior officer aboard at the time.

Commercial Code – Signalling code formerly used in merchant ships. Based on Marryat’s Code. Superseded by ‘International Code’.

Commercial Purpose – For the purposes of profit or for research.

Commis – An apprentice waiter.

Commission – Document issued by sovereign of a state and authorising a person to hold office and rank. 2. To take a naval ship out on service. 3. Document authorising an officer to take a naval ship on service. 4. Period a naval ship is on service. 5. Money paid to a factor or agent for services rendered: generally calculated as a percentage of subject matter concerned.

Commissioning Pendant – Narrow white pendant with St. George’s Cross in red at inner end. Flown by all H. M. ships in commission, excepting flagships and ships wearing a Commodore’s broad pendant.

Commodore – Naval officer senior to Captain but junior to Rear-Admiral. 2. Officer commanding a convoy. 3. Courtesy title given to senior officer of two or more warships or to the senior Master of a shipping company. 4. Senior member of a yacht club who has been elected to the position of highest rank in the club.

Commodore’s Burgee – Tapered white burgee with red St. George’s Cross. Is flown by vessels carrying a Commodore (First Class). Commodore (Second Class) has same burgee, but with red torteau in upper inner canton. A commodore of a convoy’s burgee is white with a blue St. George’s Cross.

Common Bend – Name sometimes given to a single sheet bend when not rove through a thimble.

Common Bill – Name sometimes given to a Promissory Note.

Common Carrier – One who contracts to carry any goods offered subject only to the statutory exceptions of fire, restraint of princes and act of God.

Common Ground Point: A junction point used to establish earth for an electrical system.

Common Law – Unwritten laws that, by long usage, have been accepted as having the same authority as statutes.

Common Pilotage – Name formerly given to that branch of navigation that deals with the conducting of a ship by methods that do not involve celestial observations and calculations. Now termed ‘Pilotage’.

Common Whipping – Binding on end of rope, made by passing turns of twine from an inch or two from end and towards end. Finished off by passing end of twine under last few turns.

Commutator – Drum of insulated copper discs on shaft of dynamo, Used for converting alternating current to direct current. 2, Switch for reversing direction of current.

Companion – Hood, or covering, over a ladder leading from one-deck to another.

Companion Ladder – Steps going from one deck to another below or above; particularly from poop or raised quarter deck to main deck.

Companion Stairs – Companion ladder when consisting of stairs.

Companion Way – Stairs or ladder leading to cabin.

Company Flag – Flag bearing special device of a shipowning company.

Comparison of Chronometers – Comparing the time shown by chronometer with time indicated by time signal, or by another chronometer, and recording any difference observed.

Compartment – Any one of the spaces into which a ship is divided by watertight bulkheads and doors.

Compass – An instrument that indicates direction.

Compass Bearing – Direction of an observed point or object as indicated by compass.

Compass Box – Case or box in which a compass is kept.

Compass Card – Graduated card, with its directive needles and cap, that is the essential part of a compass. Graduations may be in points, points and quarterpoint, degrees measured clockwise from north, or quadrantly, e. g. NE, 045°, N45°E. Three figure notation is now standard.

Compass Correction – As applied to a compass bearing, is the amount to be applied to the bearing to reduce it to a magnetic bearing, or to a true bearing. In former case it would be the Deviation; in latter case it would be a combination of Deviation and Variation— known as ‘Total Error’. The name of the correction will be opposite to that of the error.

Compass Course – Angle between North-South line of a magnetic compass and ship’s fore and aft line.

Compass Error – Angle that North-South line of compass makes with true meridian at a position. Is of same value as the ‘Correction’ but opposite in name.

Compass Float – Buoyant element incorporated in card of liquid compass to reduce friction between cap and pivot.

Compass Needles – Magnetised steel needles, of high retentivity, that tend to keep North-South line of compass card in magnetic meridian.

Compass Pivot – Column, in centre of compass bowl, having a needle point— usually of iridium—on which a jewelled cap, in centre of compass card, rests and is free to move.

Compass Rose – Graduated circles, on a chart, that indicate direction of true and magnetic North, and angular values from these points.

Compass Timber – Timber that is naturally bent, and is suitable for securing deck beams to frames, etc., in wooden vessels.

Compeered – Word used in Protests and other legal documents. Signifies that one person was in the presence of another.

Compensation – In ship construction, is a restoration of strength lost by a member or members being pierced or otherwise weakened. 2. Recompense for a loss sustained. 3. Magnetic adjustment of mariner’s compass.

Complement – Quantity necessary to complete a given value. 2. Correct number of men required for manning a ship.

Complete Superstructure Vessel – One of relatively small tonnage, but largecarrying capacity, resulting from having additional space not having permanent means of closing openings in deck.

Complimentary Ensign – Flag of the country whose territorial waters a ship is entering. Usually hoisted at foremast head of merchant vessel and starboard spreader of a yacht as an act of courtesy.

Component – (Of tide.) That part of a tidal undulation that is due to an actual tide raising body, or ascribed to an hypothetical harmonic constituent.

Composite – Applied to vessels built with iron framing and wood sides.

Composite Build – Composite construction.

Composite Construction – The use of a mix of materials for a hull’s construction.

Composite Group Flashing – Flashing navigational mark of a combination of alternating groups of differing numbers of flashes.

Composite Group Occulting – Occulting navigational mark of a combination of alternating groups of differing numbers of occultation.

Composite Policy – Policy of marine insurance that is subscribed by more than one company.

Composite Sailing – Method of sailing in which part of the track is a great circle, and part is along a parallel of latitude.

Composite Track – Track of vessel when ‘composite sailing’.

Compound Engine – Steam engine with high- and low-pressure cylinders through which steam passes, thus making use of expansive property of steam.

Compression of (Earth’s Axis) – Difference between equatorial and polar diameters (or radii) of Earth, when expressed as a fraction of the equatorial value: this is 1/297.

Compression Ratio – The ratio of the piston’s swept volume and that remaining unswept of the cylinder – typically 10:1 plus in petrol and 16:1 plus in diesel high speed combustion engines.

Compression – The pressure generated in the engine cylinder as the piston rises forcing trapped air to the top of the cylinder.

Compressor – A pump to compress refrigeration gasses or air.

Compulsory Pilotage – Pilotage that is compulsory, in a given area, for all vessels other than those exempt by statute.

Con – To guide or direct a ship by giving orders to helmsman.

Concealment – Deliberately, or negligently, withholding from an insurer relevant information that he would normally be unable to obtain.

Concession – A arrangement where a private party (concessionaire) leases assets from a public entity to enjoy contractual investment and termed revenue rights that revert to the public on the contract term expiry.

Conchoidal Fracture – Rupture of metal in which fractured surface has a shelllike appearance.

Concluding Line – Small line rove through small holes in treads of a wooden jumping ladder. Used for contracting treads into small space.

Conclusion stage –A period during a SAR incident when SAR facilities return to their regular location and prepare for another mission.

Condensation – Formation of liquid by cooling of a vapour.

Condenser – Chamber in which exhaust steam is led to outside surface of a number of pipes, through which sea water is circulated, so causing steam to condense into water.

Condenser Tudes – Usually about 1/2-in. diameter and made of brass or aluminium bronze. Due to expansion stresses, they are liable to leak at ends.

Conder – One who cons. More particularly, a masthead man who sights and gives notice of shoals of fish.

Conduction – Transference of heat through solid material.

Conductivity – Capacity to transmit electricity or heat.

Conductor – An electrical conductor is a material which will carry electric current. Most metals, sea-water, the earth, and your body are all conductors. The term is often used for a wire in an electric circuit. Wire conductors must be large enough to carry the circuit current without overheating.

Conduit – A pipe for cables. Confined space A tank or void space that is not normally a workspace that is poorly ventilated and may contain an atmosphere that will not sustain life.

Confluence – The join of two streams or bodies of water.

Conjunction – Position of heavenly bodies when they have same right ascension, or celestial longitude. Minor planets have two conjunctions with Sun in each revolution of orbit.

Connaissance de Temps – The French nautical almanac.

Connecting Links – Split links of C shape. Used for joining two ends of chain, or for temporarily replacing a fractured link.

Connecting Rod – Mild steel forging connecting end of piston rod and crank pin of reciprocating engine.

Connecting Shackle – ‘Joining Shackle’ of chain cable.

Conning – Directing the course of a ship.

Conning Tower – The raised surface operating control station of a submarine. A protective armour plated control station.

Consignee – One to whom goods are sent.

Consignment – That which is consigned or transferred to another. The act of forwarding goods to another. Goods placed with a carrier for delivery to a consignee.

Consignor – Person who consigns.

Consigs – A convoy signalling code book of World War II.

Consol – A long-range aid to navigation in which a radio station transmits a pattern of dots and dashes. A ship may receive these signals with an ordinary radio receiver and thus obtain a bearing of the consol station.

Console Bracket – Light ornamental work at fore end of quarter gallery of olden ships.

Conspicuous object – Readily identifiable mark useful for navigation.

Constant – Factor that is invariable in a variable quantity or value. A ‘Tidal Constant’.

Constant Bearing – Bearing that does not change although ship is moving. If another vessel be crossing on a constant bearing it must be assumed that a risk of collision exists.

Constellation – Arbitrary grouping of stars according to a fancied, or obvious, resemblance to a figure or shape. Used as aid to star identification.

Constituent – Specific part of tide. Also applied to fictitious body responsible for the part.

Constrained By Her Draught – A power-driven vessel which because of her draught in relation to the available depth and width of navigable water is severely restricted in her ability to deviate from the course she is following.

Construction Policy – Contract of insurance covering risks while a vessel is being built. Stamped as a ‘voyage’ policy. Often issued for a vessel in dry dock.

Constructive Total Loss – Said of a ship or goods when so damaged or situated that cost of salvage and repair would exceed their value when salvaged.

Consul – Agent of a foreign state who resides in a country, as an accredited agent, to promote the mercantile interests of his state and the interests of its subjects when visiting, or resident in, the country to which he is accredited.

Consulages – Consular fees and charges.

Consular Fees – Moneys payable to a consul for services rendered in his consular capacity.

Consular Flag –. Proper flag of a consul. British flag is blue ensign with Royal Arms in centre of fly. Is one of the flags authorised to be displayed afloat.

Consular Invoice – Invoice, attested by consul, that is required to accompany certain goods shipped to foreign countries. Nature, quality and quantity must be specified.

Container – Large, strong case of standard size which is ‘stuffed’ with merchandize for export and ‘stripped’ or unloaded at its final destination. Standard sizes of these metal containers are 20ft or 40ft by 8ft wide and 8.5ft high.

Container Ship – Merchant ship built to carry large containers of standard size packed with cargo.

Container Terminal – Purpose built port facilities for loading, unloading storage and stowage of cargoes in containers.

Contamination – Tainting or pollution of a substance through contact with, or near approach to, another substance.

Contents Bill – Customs document describing goods and stores shipped, and number of crew and passengers.

Continent – One of the six main continuous bodies of land on the planet.

Continental Shelf – Zone of shallow water adjacent to the continent whose seaward extremity quickly drops away to greater depth. Usually regarded as the 200mtr sounding line, but in local terminologies may mean from 100mtrs to 350mtrs.

Continuation Clause – Special contract that is inserted in a time policy of marine insurance. Undertakes that if vessel has not completed voyage when time policy expires she will be held covered at a pro rata premium until arrival, and for up to 30 days after.

Continuity – The completeness of an electrical pathway.

Contline – See ‘Cantline’.

Contour – Lines joining equal depths or heights.

Contra Propeller – A fitting on the rudder post to re-direct the flow of water from the ship’s propeller. Never in general use.

Contraband – Prohibited, illegal. Applied to goods forbidden to be imported or exported.

Contract of Affreightment –  A service contract under which a ship owner agrees to transport a specified quantity of products at a specified rate per ton. This contract differs from a spot or consecutive voyage charter in that no particular vessel is specified.

Contract Ticket – Document by which a shipowner contracts to carry a passenger other than a steerage passenger. Minimum value £25, or £3 25s. for every 1000 miles of voyage.

Contraction of Moon’s Semidiameter – Apparent difference in angular values of Moon’s horizontal and vertical diameters when near horizon. Due to unequal refraction. Was of importance when measuring lunar distances.

Contributory Negligence – Neglect which, though not being directly responsible for an accident, is one of the factors that made it possible.

Control Room – Space, insulated from heat and sound, from which machinery is controlled when the controls are not in the engine room.

Controller – Cast iron fitting, just abaft hawse pipe on cable deck, over which the cable can run freely. Has a bed that can be lowered, so causing outboard end of link to be brought up against a shaped portion that holds cable from further running out.

Controlling Depth – Minimum depth of water in an anchorage or channel.

Convection – Mode by which heat is propagated through a fluid. Heated mass rises and unheated mass descends to source of heat.

Convectional Rain – Rain caused by surface layers of atmosphere expanding and rising, so giving place to cooler and denser air. When rising air is charged with moisture, precipitation occurs.

Conventional Signs and Abbreviations – The accepted and established symbols and abbreviations used in a chart.

Convergence – Term used in cape to define a condition when more air flows into an area than out of it. This causes air to rise and results in formation of clouds and, possibly, precipitation of rain. The meeting boundary of two differing currents or winds.

Convergency – Tendency to meet at a point. Particularly applied to meridians and their inclination towards each other as they approach the pole.

Conversion – The changing of a vessel’s class by alterations, reductions or additions.

Convex Iron – Rolled steel or iron having one surface flat and the other a raised arc of a circle.

Convoy – Group of merchant vessels escorted by warship or warships.

Cooling Water – Circulated water that removes the heat from an internal combustion

Coordinated Search Pattern – Multi-unit pattern using vessel(s) and aircraft.

Coordinated Universal Time (U.T.C.) – International term for time at the prime meridian.

Coordination – The bringing together of organisations and elements to ensure effective search and rescue response. One SAR authority must always have Overall coordination responsibility and other

Copernican Hypothesis – The view held by Copernicus regarding the solar system. He called it an ‘hypothesis’ to avoid antagonising the Pope of Rome.

Copernican System – Placed Sun in centre and relegated Earth and planets to subordinate positions. Considered Earth and planets to be joined to Sun by bars. Until Kepler and Newton proved the falsity of this latter assumption the view of Copernicus was generally accepted.

Copernican Theory – Later name for ‘Copernican hypothesis’.

Coping – Former name for the turning of ends of iron lodging knees so that they hooked into beams, thus easing strains on bolts when vessel rolled.

Copper – Soft and ductile metal that forms base for brass or bronze. Is good conductor of heat and electricity. As it slowly exfoliates in sea water, it prevents accumulation of fouling when used as sheathing on underwater body of a ship.

Copper Bottomed – Said of a vessel whose bottom is sheathed with copper plates as protection against worm and fouling. First used 1761; retained fairly largely until about 1910. Still has limited use.

Copper Fastened – Applied to a vessel in which fastenings of timbers are made of copper, and not iron.

Copper Punt – Light raft on two hollow wooden floats. Used in R. N. when cleaning or painting boot top or lower area of ship’s side. Was used, originally, for cleaning copper sheathing when vessel was careened.

Cor Caroli – Star Canum Venaticorum. S. H. A. 166°; Dec. N39°; Mag. 2.9. Name means ‘Heart of Charles’, being given, by Halley, in memory of Charles I.

Cor Hydras – ‘Heart of the Hydra.’ The star ‘Alphard’.

Cor Leonis or ‘Lion’s Heart’ – Name given to star Regulus.

Cor Serpentis – ‘Heart of the Serpent’. Star α Serpentis. Mag. 2.8; S. H. A. 124°; Dec. N7°.

Coracle – Boat comprised of wickerwork base covered with skins or oiled fabric. Dates from very early times and still to be seen in Wales and Ireland.

Coral – Carbonate of lime that is formed by skeletons of polypes or zoophytes.

Coral Bleaching – Die back of corals caused by excessive water temperatures.

Coral Reef – Reef that largely consists of coral. Most important runs parallel to N. E. Coast of Australia, being about 1000 miles long and having a 350-mile length with no gap. Also found in Solomon Islands, New Hebrides and other places.

Co-range Lines – Lines, on a chart, connecting positions having the same range of tide.

Cord – Unit of measurement for small pieces of wood. Contains 128cu. ft. (4’x4’x8′).

Cord Wood – Small lengths of branches, about a foot long. 2. Wood piled up for measurement into cords.

Cordage – Collective name for all fibre ropes and lines.

Cordillera – A mountain province.

Cordonazo – Violent cyclonic storm off Pacific coasts of Central America and Mexico.

Core – The central filament in a wire rope.

Coriolis Force – The apparent force, caused by the earth’s rotation, which Force deflects moving air (and water to a lesser extent) to the left in the Southern Hemisphere and to the right in the Northern hemisphere.

Cork Fender – Canvas bag containing cork shreds and covered with coir sennit or matting.

Corkscrew Rule – Variation of ‘Ampere’s Rule’ proposed by Maxwell. Imagines a corkscrew point moving in direction of current. Then, direction of turning force—to left below, to right above—will indicate deflection of red end of magnetic needle by current below or above it.

Cormorant – Sea bird found in both hemispheres. Nearly 2 1/2 ft. long. Common cormorant is greenish-black on head, rump and lower parts; whitish collar under throat, brownish back and wings. Used by Chinese for catching fish.

Corocore – Vessel of Eastern Archipelago. Formerly used by pirates. Had one mast, carried crew of up to 60, sometimes pulled two tiers of oars. Up to 60 ft. long.

Corona – Luminous appearance, millions of miles in width, observable around Sun when totally eclipsed. 2. Luminous circle sometimes observable around Sun or Moon. Has reddish band at outer edge. Due to diffraction of light by suspended water particles in air.

Corona Australis – Southern constellation near Centaurus. ‘Southern Crown.’

Corona Borealis – Constellation between Bootes and Hercules. ‘Northern Crown.’

Corporation Flag – One of the flags of Trinity House.

Corposant – Electric luminosity that sometimes appears at end of mast or yard, or on rigging, during an electrical storm. St. Elmos fire.

Corrected Establishment – Mean value of time interval, at a given place, between transit of Moon and appearance of high water.

Correcting Magnets – ‘Corrector Magnets.’

Correction of Chart – Incorporation, in a chart, of new information issued by a hydrographer, or other authority.

Corrector Magnets – Permanent magnets placed in binnacle of magnetic compass to compensate for deviation and heeling errors.

Corrosion – The decay of a metal or alloy by chemical or electro-chemical reaction with its environment.

Corrugated Bulkhead – Bulkheads having an undulating shaped profile of grooves arranged to increase stiffness.

Corrugated Furnace – Boiler furnace enclosed in a circular tube that is corrugated to increase heating surface.

Corrugated – Materials having an undulating shaped profile of grooves arranged to increase stiffness of steel sheeting.

Corsair – Pirate. A pirate vessel.

Corvette – Historically a fine lined French twin masted square rigged vessel or a British flush single gun deck warship. Now a fast naval escort vessel.

Corvus – Small constellation S. E. of Spica. Four of its stars form ‘Spica’s Spanker’.

Cosmical – Said of a heavenly body that rises and sets with Sun.

Cospas-Sarsat System – Russian-American satellite system designed to detect distress beacons transmitting on the frequencies 121.5 MHz, 243 MHz and 406 MHz.

Cost, Insurance and Freight – Merchant’s quotation of a price that includes purchase of goods, cost of insurance and cost of freight to destination.

Cotidal – Said of places having tidal undulations at same time.

Cotidal Lines – Lines on a chart, connecting positions having the same lunitidal interval.

Cotter Pin – A split pin. After slipping through the hole of a clevis, its arms are prized open to prevent its withdrawal.

Cotton Rope – Was often used in yachts on account of its clean appearance. Very flexible when dry but becomes hard when wet. Tensile strength is less than that of manilla.

Coulomb – Unit of electrical quantity. Amount carried by one amp. in one second.

Counter – Sloping and curved underside of after part of hull abaft sternpost and above waterline. The overhanging after section of the stern.

Counter (Engine) –. Small mechanism attached to an engine to count and indicate number of revolutions made.

Counter Brace – To brace fore and main yards in opposite directions.

Counter Current – Ocean current that flows in the direction opposite, approximately, to that of main current. Equatorial counter currents are continuations of main currents after they have recurved.

Counter Rails – Ornamental moulding across square sterns of olden ships.

Counter Sea – Sea running in direction opposite to prevailing wind.

Counter Stays – Projecting timbers that support an overhanging stern.

Counter Trades – Winds on polar side of trade wind, but blowing in an opposite direction.

Countermart – To resist attack of an enemy.

Countersunk Hole – An edge bevelled hole in a plate allowing a matching tapered bolt head to seat flush with the plate’s surface.

Countersunk Rivet – A rivet head seated flush with the plate surface

Coup d’ Assurance – Firing of a gun by a warship when she shows her national ensign to vessel she is chasing.

Coup de Semonce – Firing of a shot across the bows of a vessel chased by a warship.

Coupee – Flag having vertical stripes.

Couple – Two equal forces that are parallel to each other but working in opposite directions—so generating a turning movement.

Coupling – The link between two parts of a shaft or shaft & drive system.

Courge – Small wickerwork basket towed astern of a shrimper. Prawns and shrimps are kept alive in it.

Course – Direction steered by a vessel. Angle that ship’s fore and aft line makes with a meridian, or with north-south line of a compass. May be true, Magnetic, Compass or Gyro course. 2. Sail bent to lower yard of a sailing ship.

Course Error – Error of indication, by a gyro compass, on any particular course.

Course Made Good – The track that was achieved over the sea bed (ground).

Course Recorder – Pen marking the gyrocompass heading on a rolling record sheet.

Court of Survey – Composed of a judge and nautical assessors. Has powers to order survey of a vessel, to detain or to release her, to order repairs or alterations to be made, to order a certificate of seaworthiness to be given.

Courtesy Flag – ‘Complimentary Ensign.’

Cove – Small creek, inlet or bay sheltered from wind. 2. Arched moulding at foot of taffrail.

Coverage Factor (C) – For parallel sweep searches, (C) is computed as the ratio of sweep width (W) to track spacing (S). C = W/S.

Covering Board – Plank that overlaps seam between planking of side of a wooden ship and the outboard deck plank.

Covering Note – Document in which each underwriter states his acceptance of a proportion of a marine risk by stating the amount and then initialing it. Is evidence of insurance pending issue of policy.

Covering Strap – Doubling piece covering butt of ship’s side plating, and to which the butted plates are riveted.

Cowl – Metal fitting for collecting and directing an air-stream to a particular space. The hood shaped cap of a ventilator.

Coxcomb – ‘Cockscomb.’

Coxswain – Person who steers a boat and is in charge of crew.

Crab – Winch whose axis lies in a fore and aft line. Originally a portable hand winch used in sailing ships for hauling on topsail halyards, fore and main sheets, and for working cargo.

Crabwise – Sideways movement, like a crab.

Crachin – Northerly wind bringing drizzle and mist, occurring between January and April in the China Sea.

Crack On – To carry sail to full limit of strength of masts, yards and tackles.

Crackerhash – ‘Crackerjack.’

Crackerjack – Hash made of preserved meat, broken biscuit and any other available ingredient.

Cradle – Framework of iron or wood, resting on launching ways, that supports a ship under construction for about three-quarters of her length. Slides down the ways when ship is launched. 2. Padded box in which horses, etc., are hoisted aboard. 3. Railed stage used for painting ship’s side, or for repairs, when ship is in dry dock.

Craft – Any air, sea-surface or submersible transporter.

Cran – Fish measure equivalent to 37 1/2 gallons, or 420 Ib. of herrings.

Cranage – Money paid for use of cranes. 2. Outfit of cranes in a port.

Crance Iron – Iron rigging band at extremity of jib boom or bowsprit. Sometimes applied to any boom iron.

Crane – Machine for hoisting or lowering heavy weights. Name is also given to a projecting bracket, or pillar with curved arms, used for supporting booms or spars.

Crank – Said of a vessel with small stability, whether due to build or to stowage of cargo. 2.* Iron braces that supported lanterns at quarters of poop.

Cranky – A vessel that is easily heeled or listed.

Cranse Iron – ‘Crance Iron.’

Crayer – Three-masted, square-rigged merchant vessel of Tudor times. Creek. Inlet on sea coast. Short arm of a river. 2*. Seaside town that is not of sufficient importance to be a Customs station.

Crayfish – A lobster.

Crazing – Tiny cracks which appear in the outer surface of varnish, paint or gel coat.

Creep – To search for a sunken object by towing a grapnel along bottom. 2. Gradual and steady deformation of a metal fitting when under stress.

Creeper – ‘Grapnel.’

Crepuscular Rays – Coloured rays radiating from the Sun when it is below visible horizon but above crepusculum. Results in alternate dark and light rays being visible across sky. Caused by light being broken up by clouds or intervening mountains.

Crepusculum – Twilight circle. Small circle parallel to horizon and about 18° below it.

Crescent – Moon’s shape from new moon until first quarter.

Crest – Top of a wave. The maximum positive amplitude of a radio wave.

Crevasse – Crack in an ice sheet.

Crew – The people manning a ship.

Crew Gangways – Elevated gangways provided for crew in tankers.

Crew List – Nominal list of crew, their ages, birthplaces, nationality and rating, together with other particulars. Delivered to Port Authority when required in a foreign port.

Cribbing – The foundation of heavy blocks that support a vessel during construction.

Crimp – Person who decoys a seaman from his ship and gains money by robbing him and, or, forcing him on board another vessel in want of men. To recruit a crew by trickery or hijack.

Cringle – Rope loop, with or without a thimble, worked into bolt-rope of a sail. See ‘Bowline Bridle’.

Crinolines – Small lines put on a purchase block and held in hand to steady a lifted weight.

Critical Angle – Least angle of incidence at which a light is reflected.

Critical Pressure – Of steam, is that pressure (3200 Ib. per sq. in.) at which it has no latent heat and its density is that of water.

Critical Speed – Of turbine, is that rate of revolution that is almost similar to vibration rate of turbine shaft.

Critical Temperature – Maximum temperature at which a given gas can be liquefied by pressure. CO2 is 88°F; Ammonia 256°F.

Cro’jack, Cro’jick – Abbreviations of ‘Crossjack’.

Cromster – Old name for ‘Hoy’.

Cross (in Cable) –. Exists when cables of a ship moored with two anchors lead on bow opposite to that of their respective hawse hole. Will occur when ship swings through 180° after anchoring.

Cross Bar –  Round iron bar bent to Z shape and used for turning shank of anchor when stowing.

Cross Beam – Heavy piece of timber fitted athwart a pair of wooden riding bitts.

Cross Bearings – Bearings of two or more charted objects that are taken simultaneously and laid off on chart to fix ship’s position.

Cross Channel Packet – Vessel carrying mails between southern England and coast of France.

Cross Chocks – Filling pieces put at foot of timbers at ends of wood-built ship.

Cross Curves of Stability – Graphical curves of a ship’s transverse stability for ranges of heel angle and displacement.

Cross Grip – Steel clamp for gripping two crossing wires or hawsers.

Cross Jack – Pronounced ‘Crojjik’. Lower yard on a mizen mast. Name is sometimes given to yard on which square sail of a cutter is bent.

Cross Pawl – Temporary horizontal timber holding frames of a wooden vessel in

Cross Piece – Bar of timber connecting heads of bitts. 2. Bar athwart knight heads, and carrying pins for belaying ropes. 3. Flooring piece resting on keel between half floors.

Cross Pointing – Name sometimes given to ‘Coach Whipping’.

Cross Sea – Confused sea caused by two seas that run in different directions.

Cross Seizing – Round seizing that is finished off by dipping the end between upper and lower turns and expending it around standing part of a shroud.

Cross Spale, Cross Spall – Cross pawl.

Cross Staff – Old navigating instrument. Consisted of a long batten with graduated surface. Along the batten were three sliding transoms of different length. An observed celestial body was ‘touched’ by one of the transoms, and the position of the transom in the graduations indicated the natural co-tangent of the half arc.

Cross Timber – Floor timber, of a frame, with its middle on the keel.

Cross Tired – Having tire plates, extending from mast to ship’s sides, on underside of deck; so preventing mast wedges distorting deck planking.

Cross Trees – Thwartship timbers, on a mast, to increase spread of shrouds and form support for tops.

Cross Wind – Wind blowing across course of a vessel, or across direction of sea.

Cross Wires – Wires or etched lines, at right angles, in object glass of an astronomical telescope or sighting telescope.

Crossed Observations – Sights taken with Borda’s repeating reflecting circle: first observations being taken with instrument in direct position, second observation with instrument reversed. This eliminates index error if mean is taken.

Crosshead – Lower, or outer, end of a piston rod. Carries the guide shoes and top end pin of connecting rod.

Crossing – Applied to a vessel that is on such a course that she will pass ahead of another vessel. Sometimes limited to a vessel that is entitled to cross ahead of another.

Crossing Rules – Those articles of the ‘Collision Regulations’ that refer to crossing vessels.

Crossing the Line – Crossing the Equator; traditionally the occasion of a celebration where a pantomime King Neptune and his court challenge first time initiates leading to punishments and rewards.

Crossjack – The lowest square sail set on the mizzen of some sailing ships.

Cross-planking – Plank laid in a transverse fashion, usually along the bottom of a chine built hull.

Cross-spall – A temporary horizontal brace to hold a frame in position, ultimately replaced by deck beams.

Crosstree – Spreader fixed to the mast to anchor the shrouds.

Crotch – Shaped timber resting on keel in forward and after ends of a wooden vessel. 2. Forked post for supporting a boom or horizontal spar.

Crow – Iron lever with a wedge end that is forked. Crowd. Colloquial term for ‘crew’.

Crow’s Nest – A viewing platform at the mast top.

Crowd On – To carry a press of sail.

Crowfeet –* Crowfoot.

Crowfoot – Number of small lines radiating from a euphroe or eye.

Crown – Of a block, is the head. The bottom (terminal) part of an anchor on which the flukes are attached. The camber of a deck.

Crown (of Anchor) – That part, directly beneath shank, where arms go in opposite directions.

Crown Knot – Made by unlaying end of rope, turning down one strand so that a bight is formed; passing second strand over bight of first strand; passing third strand over end of second strand and through bight of first strand; then working strands until tight down.

Crown Plait – Made with alternate crown and diamond knots.

Crow’s Nest – Protected look-out position near mast head.

Croziers – Constellation Crux Australis, or ‘Southern Cross’.

Cruise – Voyage made in varying directions. To sail in various directions for pleasure, in search, or for exercise.

Cruiser – Historically a privateer. A large lightly armoured warship with medium sized guns, used for

Cruiser Arc Lamp – Arc flashing lamp of about 900 c. p. Shutter is made up of numerous pivoted slats that turn their edges to light simultaneously.

Cruiser Stern – Stern having additional floors abaft transom so that a fuller form is obtained down to water line and above rudder.

Cruising – Sailing in different directions for the purpose of search, or for visiting different places.

Cruising Guide – Navigational booklet describing a limited area in detail.

Crupper Chain – Chain that secures heel of jib boom to bowsprit.

Crustacea – Aquatic creatures having bony casing, ten or more joined limbs and two pairs of antennae. Lobsters and crabs are examples; but there are 8000 species.

Crutch – Horizontal plate that supports side plating at fore or after end of vessel. 2. Knee timber securing cant timbers aft. 3. Crotch. 4. Swiveled metal fitting in which oar rests when rowing.

Crux – Important southern constellation. Brightest star is α Crucis. S. H. A. 174; Dec. 63° S; Mag. 1.1. is a Crucis. S. H. A. 174; Dec. 63°S; Mag. 1.1.

Cu – Abbreviation for ‘Cumulus’.

Cuckold’s Knot (Neck) – Used for securing ropes to a spar. Something like clove hitch but both ends come out in same direction.

Cuddy – Cabin in fore part of a boat or small craft. A small cabin.

Culage – Laying up of a vessel, in dock, for repairs.

Culmination – Coming to the meridian. Point at which altitude of a heavenly body has its greatest or least altitude; the former being the upper culmination, the latter the lower culmination.

Culverin – Sixteenth century cannon. From 10 to 12 ft. long and 5 1/2-in. calibre. Threw 18-lb. shot about two miles. Name means ‘Serpent’.

Cumulonimbus – Heavy mass of cloud rising to considerable height. Sometimes anvil-shaped at top. Associated with rain, hail, lightning and thunder.

Cumulostratus – ‘Stratocumulus’ cloud.

Cumulus – Dense cloud form with firm, rounded edges and horizontal base. Only moderate elevation.

Cunningham Patent Topsail – Topsail fitted to a yard that could roll up the sail to a close reef.

Cupola Ship – Early type of turret warship. Characteristic features were very small freeboard and heavy gun mounted in turret. American ‘Monitor’ was first one built, but idea was introduced by Captain Cooper Coles, R. N., some years before.

Curragh – Wooden-framed boat with skin or canvas covering.

Current – Horizontal movement of a stream of water through ocean or sea. Primarily due to wind action, but also to differences in specific gravities of water.

Current Chart – Chart in which direction and extent of ocean currents are delineated, and approximate rates noted, for information of navigators.

Current Log – Instrument for measuring rate of a current.

Current Meter – Instrument for measuring rate and direction of a current of water.

Current Sailing – Determination of position in which set and drift of currents experienced are treated as a course and distance run.

Cursor – An electronically-generated cross hair used to indicate a position on a raster scan display.

Curtain – A sagging line caused by a too much paint or varnish on a vertical surface.

Curtis Turbine – Impulse turbine that is compounded for pressure and velocity. Essentials are retained in Brown Curtis turbine.

Cushioning – Bringing to rest the reciprocating parts of an engine by leaving a little steam on exhaust side of piston. This steam acts as a cushion and prevents shock on crank pin.

Cusp – Point, or horn, of crescent Moon or other phasing body.

Custom Broker – An agent accredited by a customs authority to manage compliance for an importer.

Custom House – Office where vessels are entered and cleared, and where duty on imports are settled.

Custom of Port – Usual and established methods prevailing in a port.

Customary Dispatch – Usual and accustomed speed.

Customs – Duties imposed by law on merchandise exported or imported. 2. Common abbreviation for Custom House officers, or Custom House.

Customs and Excise – A government agency tasked with collecting and enforcing taxes on dutiable goods, particularly imports and exports.

customs charges are paid.

Customs Debenture – Authorisation for return of money paid as duty when goods

Customs Declaration – Report, signed by a sender, giving description of parcels exported from United Kingdom.

Customs Entry – Written declaration—by exporter, importer or shipper—of nature, value and weight of goods exported or imported.

Cust’s Station Pointer – Rectangular sheet of transparent xylonite with edges graduated in degrees and half degrees. Observed angles are drawn, in pencil, on under side. Douglas protractor is similar.

Cut (a Sail) – To loose gaskets and let sail fall.

Cut a Feather – Said, in 16th century, of a vessel when she foamed through the water with a breaking wave at the stem.

Cut and Run – To cut hemp cable and run from an anchorage.

Cut Splice – Made by splicing one rope to another at a little distance from end of each, so leaving a small length where ropes lie side by side.

Cut-away – An angled change in the underwater longitudinal profile of a vessel between the bow and keel or between the stern and keel. Sometimes called cut up.Cutlass bearing A ribbed rubber insert within a metal tube that allows water lubrication of an outer propeller shaft bearing.

Cutlass – Short, heavy sword used in hand-to-hand fighting at sea.

Cutter – A single-masted sailboat with multiple-head rig.

Cutter Stay Fashion – Method of setting up lower rigging. End of lanyard has knot in end, and is then rove through upper and lower deadeyes. Normally, standing end of lanyard was made fast away from deadeye. Name is also applied to a deadeye held in a running eye, or clinch, at end of shroud.

Cutting – Said of high-water levels that decrease as tide changes from spring to neap.

Cutting Down Line – Curved line on sheer plan. Passes through lowest point of inner surface of each of the frames.

Cutting Out – Capturing an enemy vessel in a port of her own country and taking her away.

Cuttle, Captain – Generous, simple and delightful shipmaster in Dickens’ ‘Dombey and Son.’ His motto was, ‘When found, make a note of.’

Cutwater – The foremost part of a vessel’s stem.

Cycle – Period in which a series of events will occur, after which they will repeat themselves.

Cyclogenesis – The rapid development/intensification of a low pressure system.

Cycloidal Propulsion System – The Voith Schneider propeller or tractor system using adjustable

Cyclone – Rotary storm in tropical latitudes. An area of low barometric pressure, though these are usually called in temperate latitudes ‘Depressions’ or ‘Lows’.

Cyclonic Rain – Rainfall associated with cyclones. Caused by elevation of an air mass that moves over a denser air mass of different temperature.

Cyclostrophic – Name applied to that component which causes a gradient wind to move outwards from its axis of rotation due to curvature of path.

Cygnus – (Swan.) Constellation between Lyra and Pegasus. Principal star is Deneb.

Cylinder – Of engine, is a tubular chamber in which piston moves reciprocally.

Cylindrical Projection – Projection of surface of sphere to inside surface of a cylinder that touches sphere on one line. Projection is by straight lines from centre of sphere. Mercator’s Projection is not of this type, though it may resemble it.

Cynosure – Constellation Ursa Major. Name was given to Polaris. As it is Greek for ‘dog’s tail’, it is obvious that the constellation was looked upon as resembling a dog.



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