C   Charlie


Cabin,  Cable,  Caisson,  Calipers,  CalkCallCalm,  Camel,  Cam cleat,  Can,  Canal,  Canal boat,  Cannon,  Canoe,  Canoe stern,  Cant,  Canvas,  Cap,  Cape,  Capsize,  Capstan,  Captain,  Car,  Carabiner,  Caravel,  Card,  Cardinal points,  Cardinal marker,  Careen,  Cargo,  Carlin,  Carpenter,  Carrack,  Carronade,  Carvel,  Cask,  Cast off,  Castle,  Cat,  Catamaran,  Catboat,  Catenary,  Cathead,  Cathouse,  Catspaw,  CaulkCB,  CE,  Ceil,  Ceiling,  Centreboard,  Centreline,  Centre of buoyancy,  Centre of effort,  Centre of gravity,  Centre of lateral resistance,  Ceol,  CET,  CG,   Chafe,  Chain,  Chainplate,  Chain pump,   Chainwale,  Chamfer,  Chandler,  Channel,  Channel markers,  Chart,  Chart datum,  Charted depth,  Charter,  Chart house,  Chart plotter,  Checklist,  Cheek,  Chest,  Chine,  Chine log,  Chock-a-block,  Chronometer,  Chum,  Chute,  Cill,  Circle,  Clamp,  Clearing bearings,  Cleat,  Clench,  Clew,  Clinker,  Clipper,  Clock,  Close-hauled,  Clove hitch,  Cloud,  CLR,  Club,  Clubhaul,  Coaming,  Coast,  Coaster,  Coastguard,  Coasting,  Coat,  Coble,  Cockboat,  Cockpit,  Cockswain,  Coffee grinder,  COG,  Cog,  Coil,  Cold front,  Collision,  CollRegs,  Comber,  Come about,  Comealong,  Come to,  Commander,  Commission,  Commodore,  Companionway,  Compass,  Compasses,  Complement,  Con,  Conductor,  Conn,  Consort,  Constant bearing,  Constrained,  Container,  Cooker,  Copper,   Coracle,  Corbita,  Cordage,  Coriolis,  Correction,  Corvette,  Cot,  Course,  Course to steer,  Crab,  Crab claw sail,  Craft,  Cramp,  Crane,  Craneline,  Crank,  Cranse iron,  Crash stop,  Crawl,  Creek,  Crest,  Crew,  Cringle,  Cross-staff,  Cross-trees,  Cross-jack,  Crown,  Crowning,  Crow's nest,  Cruise,  Crustacean,  Crutch,  Cunningham,  Current,  Cursor,  Cut and run,  Custom,  Cutter,  Cutwater,  Cyclone


n   A compartment below offering accommodations for passengers and crew.


n   A private compartment or room on a passenger ship.


n   One-tenth of a nautical mile.

In 1830 The (British) Royal Navy defined a cable as three hawser-laid (clockwise) ropes, each approximately 120 fathoms in length, laid anti-clockwise and shackled to a length of approximately 100 fathoms.   (A fathom was 6 feet (slightly less than 2 metres) so a cable was 600 ft,  about one-tenth of a nautical mile at about 6,076 feet.)


n   Pairs of electrical conducting wire encased in an insulating covering.   An electrical cable (with 2 electrical conducting,  and one earth,  wires) provides shore-power to the boat from a shore-based electrical socket.


A box-like structure open at the bottom (and sometimes at the top) which is lowered into the water so that people can work on the sea bottom or below ships.


An instrument with two legs held at one end by a spring clip or a set-screw,  with a screw mechanism for keeping the pointed tips of the legs a fixed distance apart and for changing the distance.   Used for transferring measurements.

Navigation dividers are a form of caliper for measuring distances on a chart.


Inside calipers measure the internal diameter of a cylinder

Photograph by StJohn Starkie

Outside calipers measure the outside diameter of a cylinder

Photograph by StJohn Starkie

Navigation dividers


See Caulk.


A small pipe or whistle carried and used by a boatswain to give instructions to groups of sailors.


The absence of wind.

"Sail when you can,

Row when you must,

and motor when you need to be at work in the morning"

                                                                       Alastair Law


Means of raising a sunken vessel,  or of reducing the draught of a vessel.

Two heavily laden vessels are lashed,  one either side of the vessel to be raised.   They are then emptied,  reducing their draught and lifting the vessel between them.

Nowadays (early C21) camels are used rarely:  large inflatable bags are used and pumped full of air.

Cam cleat

A small fitting with asymmetric rollers or cams, used in small sailboats to hold a sheet or ha'lyard, and from which the line can easily and quickly be freed.


n   A colloquial name for a canister-shaped buoy;  the red PHM of IALA-A or the green PHM of IALA-B.

n   The North American word for 'tin can',  the sealed metal container in which food (or,  in USA,  beer) is stored.​



A man-made waterway known,  in the UK, as a navigation.

Canal boat

A specialised vessel designed for use on a canal.   British canal boats,  or narrow-boats,  are 7 feet wide (to fit in the narrow locks and through the narrow bridges and tunnels),  up to 70 feet long and flat-bottomed.



A large-bore gun with a long barrel for firing iron balls over several miles.   During the Age of Sail they were the main armament on ships of the line and men o' war.

Cannon were often made of iron,  but the best were of bronze.   They were classified by the weight of the ball which they fired,  as 4lb,  8lb,  up to 16lb or even 32lb*.

The balls were propelled from the gun barrel by the rapid burning of gunpowder in a cartridge within the breech of the gun.   The powder burned so quickly,  and the gasses expanded so fast,  that a heavy ball could not accelerate fast enough to dissipate the energy;  balls which fitted the barrel caused the barrel to burst.   As a result,  the balls were made smaller to allow 'windage'.

See carronade.

'lb' was the abbreviation for 'pound weight',  a measure of weight now obsolescent except in the USA.   One pound (lb) is 0.453592 kilograms.   There were 16 ounces (oz) to a pound,  and 112 pounds to one hundredweight,  20 hundredweights (2240 pounds) to one ton (see cask, Thames Tonnage).   One tonne is 1000 kilograms (2204lb)


A longish,  narrow boat ,  often known as a Canadian,  or open canoe to distinguish from a kayak,  propelled by single-blade paddles rather than oars.   The paddlers face forward (in the direction of travel) and often kneel in the bottom of the vessel.

The first canoes were probably carved (or dug out) from a single large log.   Ancient dugout canoes have been found in the Netherlands,  Denmark,  the Caribbean and Nigeria dating from as long ago as 5,000 or 6,000 BC.   The people of the Pacific Northwest used them for whaling,  seal-hunting and salmon fishing.

The original North American canoes were made from a large single piece of birch bark,  framed with bent laths and stitched together with vegetable fibres.   They were built and used by the indigenous peoples long before European colonisation,  and were used extensively in the colonisation of Canada and the exploration of North America.   They were valuable because they could be carried (portaged) around obstacles such as rapids,  cataracts and waterfalls.

Toward the end of the 19th and beginning of the 20 century they were made with a wooden frame and stringers wrapped with canvas,  waterproofed.

Subsequently they were of aluminium and then various forms of plastic and fibreglass.

Canoes appear to have developed separately in very many parts of the world.

In some of the Pacific islands two canoes were often joined together by poles of wood,  to make them more stable,  and they were often fitted with sails made of leaves.

Until the middle of the 19th century canoes,  as all waterborne vessels,  were important in transport of people and freight.   This is still so in Amazonia,  where they are usually fitted with outboard motors.   Aboriginal Australian people still make and use dugout and bark canoes.

Since the end of the 19th century they have been very popular recreational vessels in a variety of sizes,  styles and shapes.

Sailing canoes have something of a cult following.

See Kayak


Two brothers,  two canoes,

on the river Cam.

The canoe on the left is made of rotomoulded plastic,  is fairly heavy and slow but can carry three people and camping equipment.

The canoe on the right was built (by the brother on the left!) from thin strips of wood glued together and covered with fibreglass cloth and epoxy resin.   The brother on the right is (unusually) using a double paddle.

Several canoes,

at Rutland Water

On the left two rotomoulded plastic canoes have been rafted together to make a very stable vessel for children and young novices.   The green canoes (in the background and on the right) are recreational 'travelling' canoes.   The two brightly coloured canoes are short 'playcanoes':  short kayaks to practice and display paddling skills.

A very old canoe,

at Beale Park

These canoes are made from thin lath planks wrapped around bent laths (ribs).   Their shape is maintained by the rigidity of the laths and gunwale and by the narrow thwarts,  all lashed together with leather strips and vegetable fibres.   there are no seats:  the paddler(s) would kneel in the bottom of the boat and use a single-blade paddle over one side.

Pigafetta wrote (as quoted by Paul Theroux in Patagonia Revisited (see periagua))

"In this place (Patagonia) they have boats,  which are made of a tree,  all in one piece,  which they call 'canoo'."

Francis Fletcher wrote "This canowe ,  or boate,  was made of the bark of diverse trees . . . It had no other closing up or caulking in the seames,  but the stitching with thongs made of seal skins . . . yet so close that it received very little . . . water at all."


Canoe stern

Where the stern of a vessel is pointed,  like a canoe.



A description of frame timbers (typically those forward,  where the bows curve inward to the stem)  not square (at right angles) to the keel.


Canvas is a heavy,  plain weave fabric originally made from hemp,  but now (early 21st century) made from cotton or linen (flax).   Duck canvas (from the Dutch word for cloth,  'doek') is more tightly woven than plain canvas.   

A generic term for any kind of sailcloth.

Modern sails are not made of canvas,  but are complex layers of several,  usually synthetic,  materials.


A block fitted over the heads of masts to support the next higher mast, which passes through a hole in the cap.


A headland,  or promontory,  which projects further into the sea than the rest of the coast,  and which marks a significant change in the trend of the coastline.

Cape of Good Hope.   Cape Horn.   Cape St Vincent.



vb   To turn over a boat so that it floats keel up. A ship will usually sink, while a small boat may stay afloat on trapped air or its natural buoyancy.

n   A situation in which a boat has capsized.


vb   To twist a knot inside out in order to untie it, especially effective with the reef knot.

vb   To invert a coil of rope,  so that it runs freely.


A mechanical device (with a vertical axis) for pulling heavy loads.   Often used for weighing anchor.   The winches on modern yachts are capstans:  most anchor 'windlasses' on modern boats are actually capstans.

See also Windlass.  


A qualified person in charge of a commercial vessel.



A movable pulley block fastened to a traveler.  They allow more subtle adjustment of the main sheet or the headsail sheets.



A metal ring or loop with a latch which can be opened and closed so that the carabiner can be attached to or detached from a line or bight.


A vessel with lateen rig on two or three masts used by the Portuguese in the 15th and 16th centuries for exploration.

Falconer wrote (in 1816) that the Spanish "caravela" referred to "a light,  round,  old-fashioned ship with a square poop".


That part of a compass on which the cardinal points,  or degrees of a circle,  are marked and which is attached to the magnets which keep the card orientated to magnetic North.   The card may balance on a pivot or be floated on oil or alcohol.

Cardinal points

North;  South;  East;  West.


North Cardinal 'Landguard'

outside Felixstowe

Cardinal marker

A Cardinal mark indicates the direction of safest or deepest water relative to the mark:  it may or may not imply the presence of a danger.   The degree of safety and the depth of water can be read from the chart.

According to Trinity House,

"Cardinal Marks are used in conjunction with the compass to indicate the direction from the mark in which the deepest navigable water lies, to draw attention to a bend, junction or fork in a channel, or to mark the end of a shoal"

Above (Left to Right): North, East, South and West Cardinal Type 2 Solar Buoys



v   A ship was moored alongside and,  by means of lines between the masts and strong-points ashore,  it was heeled over to expose its bottom for cleaning and repair.


To moor a boat in the shallows so that when the tide falls the boat is left high and dry, for the purpose of cleaning and repairing its bottom.

To secure a boat to a seawall,  or to scrubbing posts, where the bottom is exposed at low tide, for the same purpose.


To haul a boat onto a beach, for the same purpose.


Few owners now careen their boats;  most arrange for its bottom to be cleaned when the boat is lifted out of the water for winter storage.


Some authors of fiction use the word ‘careen’  when they mean ‘career’,  as in to run away out of control.



Commercial goods carried by ship (or by lorry or train).


n   A fore-and-aft structural component which links the beams together and helps to support the deck.


n   Horizontal lines from the shrouds to the mast.


One who builds or repairs wooden structures.

In the Age of Sail the carpenter was a warrant officer responsible for the hull,  spars and boats.


A three or four masted square-rigged vessel used in Western Europe in the C15 to C17.


A carronade was smaller and lighter than a cannon,  with a shorter barrel more accurately machined to fit the ball than a cannon.   The powder charge was smaller,  to reduce the effect of less 'windage'.   The ball was lighter,  being fabricated (rather than cast) and hollow.   Where a heavy iron ball from a cannon caused a round,  fairly neat,  hole in the side of a ship,  a carronade shot fragmented on impact,  showering the enemy crew with fast-moving iron shrapnel and wooden splinters.


Where the planks of a wooden boat meet edge to edge.

See Clinker,  lapstrake.


A cask is a container for liquid,  circular in cross-section,  wider in the middle than at each end.   Traditionally,  casks were made of wooden staves,  shaped and fitted together and held with iron hoops.   The base and the lid were of wood.   They held liquids because the staves fitted together closely and,  when wet,  they swelled and closed any tiny gaps.

Modern casks may be made of metal or plastic.

A barrel is a relatively small cask to hold 36 Imperial gallons.   (A barrel of oil is 42 US gallons (35 Imperial gallons))

A tun is a larger cask to hold 216 Imperial gallons of beer,  or 252 gallons of wine,  weighing 2,240 lbs (one ton).   It originated as a means of measuring large volumes of alcohol,  and for calculating the tonnage of ships.   See Thames Tonnage.

A firkin is a smaller cask to hold 9 Imperial gallons.   This is the standard size of cask in which beer is sold to English pubs.

Large wine (port) casks at the Sandeman cellar in Porto


Through the centuries ale casks,  beer casks and wine casks held different volumes;  the volume of a gallon changed several times until the standardization of the Imperial gallon (which,  again,  is different from the American gallon)


The carracks and caravels of the 14th and 15th Centuries had fighting castles at each end of the ship.   Archers high in the castles would shoot arrows down at the sailors and officers in the enemy ships.

Illustration from Chatterton.

Castles on a 14th century ship


Cast off

To let go the mooring lines in order to get under way.


v   To stow the anchor and secure it,  especially to a cathead.


 Grapnel anchor catted to a davit on the port bow of a Rhine barge.

n   A 'cat o' nine tails' was a whip with nine lengths of rawhide (nine tails) used to flog sailors convicted of shipboard crimes.   It caused dreadful wounds which were treated with salt (hence rubbing salt into a wound) but often resulted in death from infection or loss of blood.

It was normally kept,  by the boatswain's mate,  in a baize bag:  a shipboard crime would "let the cat out of the bag".

Flogging was carried out on deck because there was "not enough room to swing a cat" below decks.



n   A boat with two identical hulls and a bridge deck connecting the two hulls.


n   A floating platform,  or raft,  moored alongside a vessel,  on which workers can stand to paint or caulk.

n   Originally,  a kind of raft,  made of three pieces of wood lashed together and used especially at Madras,  on the Coromandel Coast,  to carry messages (sometimes people) through the dangerous surf.

Cat boat

A typically North American boat having a single sail with the mast stepped between the bows,  close to the stem,  and having a long boom,  perhaps overhanging the transom.   They are very broad in the beam and stern.

Cat boats are very popular in the USA.

In the UK they were known as Una boats,  and are now less popular:  on a broad reach or a run they had significant weather helm and could be difficult to control.


A catenary is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends.

The catenary curve has a U-like shape, superficially similar in appearance to a parabola.

An anchor rode is a chain or cable supported at the stemhead and the sea bottom:  it hangs in a catenary.




A strong wooden beam projecting at about 45° from each of the bows of (usually) a square rigged ship,  and used to carry the anchor securely away from the ship’s timbers when not in use.

The outer ends of the catheads were usually carved with a cat’s or lion’s head:  it’s not clear whether the name or the carving came first.


n   A brothel.

n   A channel marker in the River Orwell opposite a house of the same name.

Smugglers sailing up the Orwell would look for the lighted windows of the cathouse;   If a black cat sat in the window it was an indication that the Revenue men were on the lookout.



A light wind in a calm causes localised ripples on the sea surface.


To pack oakum (or similar) into the seams between wooden planks to prevent the passage of water.   After caulking the seams may be payed with pitch or a synthetic waterproof compound.


Centre of buoyancy.



Centre of Effort.


v   To overlay with wood,  plaster,  etc


ng    In wooden boats the ceiling forms a wall on the inside of the frames between the deck and the turn of the bilge.   There is a gap,  the width of the frames,  between the ceiling and the hull which provides ventilation of the bilges by convection.   There is often a gap between the planks of the ceiling.

Ceiling may also strengthen the hull.

In a house,  the ceiling is a layer of plaster,  or lath and plaster,  below the beams which support the floor above.   The non-supporting walls of houses usually have ceiling on both sides of the timber studding.


vb    To ceil a boat is apply a ceiling inside the frames.




A kind of leeway-resisting keel which swings up and down on a pivot.   The board is lowered when beating and raised when running before the wind and when the boat is on its trailer or in shallow water.   Centreboards are mounted within the boat,  inside a centreboard case,  or trunk,  usually (but not always) on the centre line of the boat.

Not to be confused with daggerboard or leeboard,  although all three perform the same function.


From 19th Century

On these sailing dinghies, you can clearly see the difference between a centreboard and a daggerboard. Illustration Claudia Myatt.


In his 1906 treatise Folkard describes a "centreboard keel" of 1774 as a plank "extending about two-thirds the length of the keel" on a boat brought by Lord Percy from Boston to Britain.

The 'revolving keel',  invented by Captain Shuldham,  RN,  in 1809 became the centreboard that we recognise today (early 21st Century).

Centre of Buoyancy (CB)

The water around a boat exerts an upward force,  opposing the downward force of gravity,  keeping the boat afloat.   This upward force,  buoyancy,  can be supposed to be exerted through a single point within the boat.

The boat is stable,  afloat,  when the centre of buoyancy is in the same vertical line as the centre of gravity (CG).

As the boat heels or the immersed shape of the boat changes and the centre of buoyancy moves;   the boat becomes stable again when the CB and the CG are in the same vertical line.

A boat lists because her Centre of Gravity has moved (her cargo has shifted) and she lists to bring her CG and CB in a vertical line

See AVS.

Centre of Effort (CE)

The wind in the sails of a boat can be thought of as exerting a force on the boat at a single point,  not usually at the mast.

Centre of Gravity (CG)

The hypothetical point at which the entire vessel might be suspended and remain at equilibrium. The point at which one can hypothetically presume the entire mass of the vessel is concentrated.

Centre of Lateral Resistance (CLR)

All the underwater profile of a boat resists leeway,  but the force exerted can be thought of as acting at a single point,  the centre of Lateral Resistance (CLR).



An imaginary line from stem to stern;  the centreline is actually a vertical plane from the middle of the stem to the middle of the stern.

On the lines drawings of a vessel the centreline is a line on each of the waterline sections and on each of the body sections.


A type of wide-beamed,  flat-bottomed sailing vessel,  perhaps not unlike the Humber keel,  used as trading and transport vessels by the Anglo-Saxons in the 10th & 11th centuries.



Central European Time.   In nautical terms,  Time Zone -0100:  in terrestrial terms,  Time Zone UT+1.

See Time,  Zone,  UT.



Centre of Gravity.


To rub against another part so that it wears (away).

At anchor for a long time the constant movement of the boat causes the chain to chafe against the hawsehole or fairlead;   if the rode is line it will chafe against the fairlead and,  perhaps,  part (break).

When running downwind for long periods the sails may chafe against the shrouds.




n   A length of interconnected metal rings used for lifting heavy objects and as part or all of the anchor rode.


n   Falconer described 'chains' as "strong links or plates of iron ,  the lower ends of which are bolted through the ship's sides to the timbers.".   these are equivalent to our modern chainplates.   See Channel.


n   An archaic and almost obsolete unit of length,  equal to 66 feet, or 22 yards, or 100 links,  or 4 rods (20.1168 m). There are 10 chains in a furlong, and 80 chains in one statute mile. An acre is the area of 10 square chains.

This is important because a cricket pitch is 1 chain between wickets,  and because horse-race courses are measured in furlongs.



A steel plate attached to the topsides of the hull to receive the lower ends of the shrouds.

Chain pump

An endless chain,  with leathered washers (or saucers) at intervals,  riding on a sprocket wheel on deck and a roller in the well.   It passed downward through the back-case,  through the well (sump) in the bilges of the ship and then upward through a pipe into which the leathered 'saucers' fitted.   The spaces between the 'saucers' carried water upward through the tube and out of the bilges.

An efficient chain pump,  well manned,  could draw a tun of water every minute.

When the well was empty a chain pump would draw stale,  foul air out of the bilges to be replaced by fresher air from above.


Chain wale.

A wale is a plank in the side of a ship thicker and stronger than the surrounding planks.

The chainplates of the shrouds of square-rigged ships were attached to the chain wales,  or cha'n'l's.

See Channel.

A ​partial bevel cut into the edge of a piece of wood.

See bevel.


A purveyor of items needed on boats.

Modern-day chandlers seem to stock more clothing than hardware.

Bevel & chamfer

Harry Bryan,  2010,  Wooden Boat Magazine No194, p26




n   A deep water route along an estuary or inlet,  marked on one side by red buoys and on the other by green buoys.   Ships may be constrained to the channel by their draught:  smaller boats,  which are not so constrained,  should keep clear.

The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) has divided the world into Region B (America and Japan) and Region A (the rest of the world).

In Region A the red can-shaped buoys are on the left side of the channel when returning to harbour;  the green conical buoys are on the right hand side of the channel when returning to harbour.   

In Region B the red conical buoys are on the right hand side of the channel when returning to harbour and the green can-shaped buoys are on the left.

Ships using a channel may be constrained by their draught;  they are then stand-on vessels and others are give-way vessels.   IRPCS Rule 9.

n   Stout pieces of timber bolted on the outside of a vessel, to which the dead-eyes of the rigging are fastened.   A corruption of ‘chain-wales’,  or 'chan'l's'.   The photograph of The Amsterdam (on the right) shows cha’n’l's very clearly.



Channel markers

(Lateral Marks)

In IALA region A channels are marked on their starboard side (returning to harbour) by green conical buoys,  sometimes with green lights,  and on the port side of the channel by red can-shaped buoys,  sometimes with red lights.

According to Trinity House,

"Lateral Marks are used generally to mark the sides of well-defined, navigable channels. They are positioned in accordance with a Conventional Direction of Buoyage"


Above (left to right): Port and Starboard Lateral Marks


A representation of part of the spherical Earth on a flat piece of paper,  or on a computer screen.

Charts used for coastal navigation are modified by Mercator’s projection,  a fairly complex equation.   The parallels of Latitude on the surface of the Earth remain parallel across the chart.   The Meridians of Longitude,  between the Poles,  which are not parallel on the Earth,  become parallel on the chart.   At the Equator the distortion of scale is minimal;  at the Poles the distortion is total in that the point at the poles,  which has no distance in any direction on the Earth,  becomes a “parallel of Latitude”on the chart as long as the Equator.   The scale of Latitude,  on each side of the chart,  measures angles (in degrees, minutes and decimal minutes) North and South of the Equator subtended at the centre of the Earth.   Each minute of arc is one nautical mile on the sea surface.

Charts show the positions of features such as land masses,  wrecksbuoys & lightsTraffic Separation Schemes,  harbours,  gas & oil rigs,  wind farms.   They carry abbreviated information about most of these features.   They have curved lines,  or compass roses,  showing magnetic variationdiamonds giving data about tidal streams and numbers showing charted depth (ie,  depth below chart datum). 

Each chart has a title page with a wealth of information about that chart,  and notes about special features and restrictions on the chart.

Chart Datum

The level of Lowest Astronomical Tide;  ie,  the lowest level of tide which can be calculated from the positions of the sun, the moon and the earth.   A constant level at any Standard Port.

Charted depth is measured below chart datum.

Tidal height is measured above chart datum.

Depth of Water = Charted Depth + Height of Tide

Charted Depth

The vertical distance from Chart Datum to the seabed.   The Depth of Water is the sum of the Charted Depth and the Height of Tide.   At any point on the chart,  charted depth is represented as a number followed by a subscripted number.   The number is usually metres below chart datum:  the subscripted number is decimal (tenths) metres.   In some places on the chart (usually coloured green) the numbers are underscored to show that they are negative and that the seabed is above chart datum.


v   To hire a boat for a period of time.

A skippered charter is where the owner provides a skipper (and sometimes a cook) to sail the boat on behalf of the people chartering the boat.

A bare-boat charter is where a group of people,  the charter party,  sail the boat themselves.

Chart house,  chartroom

The structure,  often on deck,  from which a vessel is navigated.

In a modern navy ship the chartroom is safe below decks.

Chart plotter

An electronic device which has a GNSS and electronic charts,  and which indicates the ship’s position on the electronic chart.   It may be combined with AIS to show the position and tracks of other ships,  and with radar.   It may be linked to wind instruments to show the true and apparent wind and with an electronic sounder to show the depth of water.   It may contain,  or be linked to,  a tide calculator to show the height and stream of the tide.

Chart plotter


A list of things to do or items to obtain;  each item is ticked off when completed.

Every skipper will have a list of items and procedures to be checked before embarkation and before casting off.

All pilotage plans will carry a list of buoys and marks to be passed;  a tickmark should be made against each buoy on the list with the time it is passed.


The sides of a pulley block.   The pin around which the sheave rotates is fixed in a cheek at both ends.


n   A lockable lidded box for storing tools or clothes.

n   A fund of money from which selected (usually disadvantaged) people benefit,  typically in the form of a pension.   The Chatham Chest was the world’s first funded occupational pension scheme.


n   The edge,  or discontinuity between the topsides and bottom of a flat bottomed or V-bottomed boat.

To Falconer,  in 1815,  a chine was " . that part of the waterway which is left above the deck,  that the lower seam of spirketting may more conveniently be caulked."   The waterway was (and still is) a strip of wood linking the deck to the topsides.   It was L-shaped in section,  and grooved in the inner corner,   to catch the water running off the deck and carry it forward or aft to the nearest scupper.   The spirketting was the strake of planking above the outer part of the waterway up to the cill of the gunport.

This meaning of 'chine' is now obsolete.

Chine log

A length of wood,  or similar,  to support and strengthen the chine.   It may be internal or external.



When the upper and lower blocks of a tackle touch each other and can be hoisted no higher.


A very accurate timekeeping instrument.

In order to measure longitude at sea clocks and watches needed to be accurate to within a few seconds each day.

In the late C20 and early C21 GNSS instruments provide accuracy better than chronometers.



Also known as an angel,  kellet or sentinel.

A heavy weight suspended halfway along the anchor rode to break the catenary and to bring the lower part of the rode more nearly horizontal.   A chum is particularly effective when the rode is all rope,  or when the wind or tide is strong.   It reduces the shock on the boat and fittings when the rode is jerked straight during a gust.


If a heavy weight is needed it’s probably better that more or heavier chain is incorporated into the rode.


A slang word for a spinnaker,  derived from the supposed similarity of a spinnaker to a parachute.   (In fact,  a conventional spinnaker does not behave in any way like a parachute.)

A cruising ‘chute is a large,  lightweight,  foresail hoisted on its own ha’lyard and luffwire.   Whereas a spinnaker is symmetrical (the luff may become the leech,  the tack may become the clew,  and vice versa) a cruising ‘chute is asymmetrical:  the luff and leech,  tack and clew are not interchangeable.   The head of a cruising ‘chute is attached to a ha’lyard at,  or near,  the top of the mast.   The tack is attached to the stemhead or bowsprit.   The clew usually has two sheets,  the ‘lazy’ sheet passing in front of all stays.   It is easier to gybe a cruising chute than to turn to windward.

Neither sail is a stay-sail.



a shelf or slab of stone, wood, or metal at the foot of a window,  opening or doorway.

A gunport would have a cill at the bottom of the opening and a transom at the top.

In modern ships the cill of a doorway is replaced with a coaming.

Lock gates rest on a cill of concrete,  stone or wood.   The cill is usually higher than the river or canal bed.


n   A fore-and-aft timber fixed inside the top of the frames and under the deck beams,  which they help to support.

v   To clamp:  to hold two things together with a cramp.

The metal tools,  with two plates which are pushed together by a screw thread,  which are used temporarily to hold two pieces of wood together are 'cramps',  but because they are used to clamp pieces together they are often known as 'clamps'.


 It is the set of all points in a plane that are at a given distance from a given point, the centre;

The Equator is an imaginary circle around the Earth which,  at all points,  is equidistant from the North Pole and equidistant from the South Pole.

Any meridian of longitude is an imaginary half-circle around the Earth which passes through both the North and the South pole.

Each of the parallels of latitude is an imaginary circle around the Earth parallel to the equator,  all points of which are equidistant from the nearest pole.   Each of the poles can be thought of as a parallel of latitude with zero radius.

A great circle is an imaginary circle around the Earth at the greatest possible diameter.   An arc of a great circle is the shortest distance across the surface between two points on the surface.


Clearing bearings

See 'bearing'.


A means of securing two pieces of wood,  such as the planks of a boat,  together.

A small hole is bored through both pieces,  and a nail is driven through the holes.   As the point emerges from the hole it is turned over by a metal block,  or a hammer,  so that it forms a hook which bites into the wood.

Strictly speaking,  the use of a copper nail and rove,  whilst possibly more secure,  is not a clench.

The word 'clinker',  of a boat with overlapping nailed planks,  derives from 'clench'.



The aftermost lower corner of a sail.   A clew-line (clewlin’) is a line which draws the clew of a sail closer to the spar above it.   A sheet (line) is a line which controls the angle of the sail to the wind (the angle of attack).   On the mainsails of modern (early C21) boats the control line is attached to the end or the middle of the boom:  it is in fact a guy line more nearly analogous to a brace,  but is still called a sheet.

An outhaul line draws the clew further aft along the boom and tensions the foot of the sail.



A shaped piece of wood or metal for temporarily and occasionally belaying lines,  such as sheets,  mooring lines,  ha'lyards.


In his plans for Paradox,  Matt Layden often refers to battens of wood as cleats;  this misuse may be spreading,  though I can find no historical precedence for this definition.

Wooden cleat on tb Hydrogen
 Cleats on the workboat Provider

A method of building small boats where the planks,  or strakes,  overlap along their edges and are held together and to the frames (ribs) with clenched nails or copper nails and roves.

In the USA the word lapstrake is used.

Simulated clinker boats are built of plywood strakes glued with epoxy resin.

Clinkeer dinghy

A fast square-rigged ship of the C19.   They had three or more masts,  a long,  low hull and a sharply-raked stem curving forward to the bowsprit.   Typically,  they were used in the tea trade,  and raced one another to get the tea first to market.   In "The Last Grain Race" Eric Newby describes his experience aboard Moshulu,  the last of the grain clippers.


An instrument for measuring the passage of time and for telling the time of day.

Analogue clocks have a circular dial (face) with two (or more) needles (hands).   Most analogue clocks have numbers around the circumference of the face from 0 to 12 hours;  some have numbers from 0 to 24 hours (because there are 24 hours in a day).   The positions of the two hands show the hours and minutes

Digital clocks have a LED display which shows the time with arabic numerals.

There are very many variants of both types.

Clockwork clocks have gears driven by either a coiled spring and escapement or by a pendulum and escapement.   Pendulum clocks are useless at sea because the movement of the vessel disturbs the rhythm of the pendulum.   (Although John Harrison devised mechanisms for using pendula at sea.)

Virtually all modern clocks are electric.   The timing may be by a calibrated electronic circuit,  by the vibrations of Caesium atoms within the clock or by adjustment of the clock by a remote atomic clock.

The passage of time is closely related to (perhaps even defined by) the rotation of the Earth and therefore by the apparent movement of the stars across the sky.   A given star can be expected to be at a given meridian at the same time every day.   It follows that,  given an accurate clock,  an observer can calculate his own meridian from the position of that star.

But clocks vary widely in their accuracy.   The most accurate clocks are known as chronometers,  but the most accurate timekeepers are probably the clocks in a GNSS instrument.

See 'watch',  'longitude'.


Said of a vessel when she is sailing as close to the wind as possible.   The wind is then blowing onto the port or the starboard bow and flows along the sails from luff to leech.   If the sails are full the vessel is Full and By.

The boom of a fore-and-aft rigged vessel is hauled close to the centre line;  the clew of the staysail (jib or genoa) is hauled as close to the centre line as possible.

On a square-rigged vessel the tack (fore-clew) of the course sail is hauled as close to the windward bow as possible;  the sheets are hauled as close to the leeward rail as possible.

Clove hitch

A temporary hitch to fasten a line to a spar or a warp to a bollard.



When the temperature of air saturated with water vapour falls below the dew point the water vapour condenses as droplets,  which form clouds.   The droplets do not precipitate,  but remain in suspension in the air,  until they coalesce into drops.

Nimbus clouds are rain clouds.

Stratus clouds appear in layers below 2000m.

Cumulus clouds are heaped up,  and may rise to 11 km or higher.

Altus means high:  altus clouds occur between 2000 and 7000 m high.

Cirrus clouds are whispy,  feathery accumulations of ice crystals above about 6000 m high.

Clouds,  and their direction of movement,  are useful clues in weather forecasting.


Air-borne water droplets close to the surface of the earth are known as mist or fog.

See Cloud Appreciation Society.



Centre of Lateral Resistance.



A group of like-minded people who meet to achieve a common aim.

Yacht clubs,  sailing clubs and dinghy clubs are groups of people who sail or talk about sailing.


Any vertical surface on a ship designed to deflect or prevent entry of water.

Combing is the act of passing a comb through hair or sand.   See Beachcomber and comber.

Club Haul

When it was vital that a square-rigged ship change tacks without falling into irons an anchor would be lowered to the seabed at a critical point of the tack in order to drag the ship’s head around onto the new tack.

Not to be confused with boxhaul.


The land close to the sea;  the sea close to the land.


A coastal trading vessel.   A trading vessel which remains within sight of the land.


In the UK,  the Maritime and Coastguard Agency.


Sailing along the coast.

coll   Doing something without effort.



n   A layer of paint,  varnish or tar.   Wood is coated to prevent damage from water and to enhance its appearance.   Metal is coated to prevent water and air causing rust.

v   To coat is to apply a layer of protective paint or similar.



A boat with a deep forefoot,  flat bottom toward the stern and a high,  flat,  raked transom with a deep rudder angled forward under the boat.   They had one or more raked masts setting standing lug sails.   They were typically used for inshore fishing in the East and North East of England,  where they were drawn backwards onto the beach at the end of a cruise.





Compartment on a sailing warship where the wounded and ill were tended.

The coxswain’s station in a Royal Navy ship, and later the location of the ship's rudder controls.   In a yacht,  the place from which the crew controls the boat.

Any well,  or sunken space,  on the deck of a small craft,  often with coamings.

Cockswain (Cox’n)

n    A sailor who operates the ship’s launch.


n   The crewman who steers a racing shell and controls the rhythm and speed of the oarsmen.


The person who steers a yacht is now known (whether man or woman) as the helmsman rather than the cox’n.

see Cockpit.


Coffee grinder

Slang term for a winch with opposing double handles used on racing yachts.


A clinker-built sailing vessel with one mast and one square-rigged sail,  developed in the 10th Century and used in Northern Europe until the 14th Century,  especially by the Hanseatic League.   Typical seagoing cogs ranged from about 15 to 25 meters (49 to 82 ft) in length, with a beam of 5 to 8 meters (16 to 26 ft) and were 30–200 tons burthen.   Cogs were rarely as large as 300 tons although a few were considerably larger, over 1,000 tons.   The rudder was mounted at the stern on a heavy post';  quite different from the 'steerboard' of Scandinavian vessels.

 Chatterton describes a cog as "of Scandinavian origin and probably somewhat bigger than the skuta",  perhaps meaning that they were long and narrow with a single square-rigged sail.



Course over the Ground.



n   The way in which lines are arranged in rings or circles so that they can be hung on cleats,  pins or beckets above the deck.

Flemish coils are decorative spirals of line laid flat on the deck.   They leave dirty,  unbleached marks on the deck,  they grockle when the line is put to use and they tend to slide off the deck and into the propeller.

v   To coil a rope or line.

New rope comes in coils held with lashings of small stuff or wire.   The rope must always be used from the centre of the coil,  not the outside.

Smaller stuff comes wound onto reels of wood or plastic,  and should be used from the outside of the reel.

A coil of 12mm rope and a reel of smaller stuff
Cold front

A cold front forms when a mass of colder air moves around a depression toward a mass of warmer air.   Being denser,  the colder air sinks beneath the warmer air,  displacing it upward.   Turbulence and mixing at the boundary cause localised condensation of water from the warmer air:  this falls as heavy rain squalls.


When two vessels touch one another.

A collision between two Mirror dinghies is a trivial and inexpensive event.

A collision between two supertankers or two liners is a major,  possibly fatal,  international disaster.

The IRPCS were drafted to reduce the chances of collisions at sea.





n    Someone who combs.

A beachcomber combs the beaches for objects of interest or value,  often using a large comb similar to a garden rake with long tines.


n    A large wave which breaks at sea.

Come about

To change tack.



A mechanism with a handle and ratchet for increasing the tension on a line.

Come to

To stop a sailing vessel by turning into the wind.



n   A Royal Navy officer next in rank below a Captain.   Equivalent to an Army Major.

n  A large wooden mallet.



A warrant of office granted by the Admiralty to Lieutenants,  Commanders,  Captains and Admirals entitling them to be paid at their rank.

A warrant appointing an officer to a designated ship.


An officer in the Royal Navy appointed to a detachment or flotilla of several ships for a detached service.   Equivalent to a Brigadier-General in the Army.



A stairway on a boat leading from one deck to another.   Any stepped passageway used to go from one deck to another.



A magnetic compass is a navigational instrument for determining direction relative to the Earth's magnetic poles.

It is subject to the variation between True North and Magnetic North,  and to the deviation caused by electromagnetic influences aboard the boat.


A fluxgate compass responds to the Earth’s magnetic poles,  but has electronics which adjust for variation and deviation.


A gyroscopic compass has an internal gyroscope which maintains its orientation independently of the boat’s heading and of the poles.   It is usually adjusted for True North.



A steering compass is used by the helmsman to orientate the head of the boat.   On a yacht it is usually a magnetic compass,  but may be fluxgate.   On larger vessels it may be gyroscopic.

A typical steering compass for a small boat.

Steering compass


A bearing compass is used to take bearings (angles relative to Magnetic North) of distant objects from the boat.   A bearing compass may be fixed or hand-held.   Fixed bearing compasses,  on larger vessels,  may be enslaved to the main,  or steering,  compass.   A hand-held bearing* compass is usually magnetic:   although its deviation could be measured it varies as the instrument is carried around the boat,  and is usually ignored.


*Please.   Not a hand-bearing compass.



A pair of compasses;  Drawing compass.

A pair of pointed metal or plastic legs,  hinged together at one end;  one of the legs has an attachment for a pencil or pen.

The instrument is used for drawing circles,  or arcs of circles of predeterminable radius.

A beam compass has a pair of trammel points which can be attached to a beam of any length for drawing arcs of any radius.

See Dividers;  Calipers.

Drawing compass

The beam attaches to increase the radius of arc

A pair of trammels fixed to a rule of any length

The pencil draws,  and the marking knife cuts,  circular arcs


The number of people in a vessel's crew.   The complement completes the crew.

A compliment is uncalled-for,  unexpected praise.


Originally,  a machine for calculating (computing) numbers faster than people.

Modern computers can calculate the numbers (0 and 1) into letters,  symbols and pictures,  and can communicate by radio waves with other computers.

They have become ubiquitous,  and are used to control washing machines,  lawn mowers,  cars,  telephones,  robots and boats.

A computer in a handheld GNSS instrument receives radio waves from several satellites,  converts the signals into time and then into a position on the Earth's surface.   It 'remembers' the data and uses it to calculate a Course over the Ground and an Estimated Time of Arrival.

The instruments (such as the log,  the wind speed indicator,  the GNSS,  the AIS,  the Radar) all contain computers which translate radio and electronic signals into visual displays.   The instruments are often interconnected,  either by their individual computers or by a master computer so that each can use data generated by the others or data from any can be displayed on a single LED screen.


The position of responsibility and authority for the operation and steering of a boat.


A lightning conductor is a bar,  or thick wire,  of copper or lead running from an antenna at the top of the mast to a metal plate in the sea.   It attracts and safely conducts lightning away from the boat.


v   To direct the progress of the vessel.


Any vessel sailing in company with another.

Constant bearing

When another vessel is on a constant compass bearing,  over time,  there is a danger of collision,  especially if the range is decreasing.



Something constrained has limited freedom of movement or choice.

IRPCS Rule 3,  "General Definitions" says:

"The term" vessel constrained by her draught" means a  . . . 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."

IRPCS Rule 10 describes the constraints within and near Traffic Separation Schemes.


A standard-sized metal box,  20-foot-long (6.1 m) by 8 feet wide,  with standard attachment points and fittings,  which can easily be transferred between different modes of transport, such as ships, trains and lorries.

Occasionally containers are washed from the decks of ships and float with only an inch or two above the surface.   Although rare,  this flotsam is very dangerous to fast small boats.



A device used to cook,  or heat,  food.

Most cookers on small boats are powered by gas.

On larger vessels they might be powered by diesel fuel.

On power-driven vessels the cookers may be powered by electricity.

Cookers aboard boats are gimballed to keep them upright.   There is a danger that when the cooker door is opened the cooker's centre of gravity moves and the contents might slide out onto the cabin sole.   DAMHIKT.


Copper is a metallic element which is malleable and ductile,  polishes to a beautiful shine,  and is biocidal.

During the later years of the Age of Sail thin sheets of copper were nailed (with copper nails) to all the underwater surfaces of a ship to deny access to the wooden planks and timbers by marine weeds,  barnacles and wood-boring worms and molluscs like Teredo.   Anything which started to grow on the copper was soon poisoned.

Copper-sheathed ships were "copper-bottomed investments",  unlikely to be destroyed by Teredo or slowed by weed.

It's not easy to nail copper plates to the bottoms of fibreglass boats.   Instead,  liquid resin is loaded with finely divided copper powder and painted onto the boats' bottoms.   The exposed particles of copper resist (poison) marine growth.   See Anti-fouling.

Being malleable,  ductile and biocidal,  copper is an excellent metal for making nails and roves:  they do not rust and they protect the wood from moulds,  weeds and worms.

Bronze is an alloy of copper and other metals.   It does not rust and is harder,  less ductile,  than copper,  so bronze nails and bolts do not stretch under tension.   The best cannon were made of bronze.

When a new mast is stepped into a boat it is traditional to place a copper coin between the wooden step and the wooden mast;  this brings 'luck' to the vessel.   The mast step is always wet from rain which runs down the mast;   the lucky copper coin is biocidal and poisons any rot which threatens to develop.

North American boats are even more 'lucky',  having silver coins,  often dollars,  placed in the mast step.   Silver is also biocidal.

21st century British copper coins are actually copper-plated steel;  their biocidal effect might be quite small.


A small round, light boat made of skin  or canvas stretched over light hooped frames, once common on the Welsh rivers.

The coracle on the right was seen at Beale Park Boat Show.


A Roman merchant vessel,  with a large square-rigged sail and a divided raffee on a single mast and a square-rigged steering sail (the artemon) on a steeply raked foremast or bowsprit.   It had two steering oars,  and could carry 600 tons of cargo.   These ships carried Roman trade throughout the Mediterranean Sea and Northern Europe.

Illustration is a line drawing by Maurice Griffiths.


A generic term which includes all rope,  line and small stuff aboard ship:  it includes the standing and running rigging,  the rope still in coil and all the line in use.


French scientist Gaspard-Gustav de Coriolis described the effect of a moving mass in a moving frame of reference.

In meteorology the Earth is a moving (rotating) frame of reference while the wind (molecules of air) is the moving mass.

The Coriolis force,  initiated by the rotation of the earth,  causes the wind moving across the surface of the earth to appear to follow a curving path.

In the Northern hemisphere the wind turns to the right,  in the Southern hemisphere it turns to the left.

An air mass moving North in the Northern hemisphere,  from latitude 30°-ish North toward latitude 60°-ish North turns to the right (the East).   Such an air mass moving over the North Atlantic becomes the prevailing warm,  wet S'Westerly wind which blows into the British Isles.

A mass of air moving South from the North Pole to latitude 60°-ish North turns to the right and becomes the cold,  dry N'Easterly North of the British Isles.

The junction between the warm,  wet S'Westerly and the cold,  dry N'Easterly is called the Polar Front;   the large scale turbulence of the two opposing winds creates the cyclonic low pressure areas typical of latitude 60°-ish North.


Charts are correct only at the moment of publication.   After publication,  harbour masters move buoys and surveyors discover new features:  charts need to be corrected and brought up-to-date.

Corrections are published in 'Notices to Mariners' and on the Notices website;  on the paper charts corrections should be made in magenta ink.



Magnetic steering compasses are affected by magnetic influences within the vessel;  deviations are recorded on a Deviation card kept at the chart table and near the binnacle.

The deviation of magnetic steering compasses may be corrected by the adjustment of iron spheres close to the compass.


Fluxgate compasses can be corrected by adjustment of the electronics within the instrument.   The compass may be adjusted to read Magnetic or True.


A sailing warship of C17,  C18 and C19,  with a flush deck and a single deck of guns.

A sloop of war.


A bed consisting of a canvassed frame,  6 feet (2m) long by 1 foot deep by 2 or 3 feet wide,  suspended from a deck beam.   Not a hammock.


n   The direction in which the boat is going over the ground:  the Ground Track.  

The Course to Steer,  as defined by the RYA,  is the compass heading calculated from the desired Ground Track and the tidal stream,  but before allowance is made for leeway.*

Falconer,  in 1815,  defined a ship's course as "the angle which a ship's track (the angle which the rhumb-line on which it sails) makes with the meridian".


n   The lowermost square-rigged sail on a mast.   There is no yard below the course,  and so the tack is drawn  to the windward bow by the tackline and forward by the bowline;  the clew is hauled aft by the leeward sheet.

*this definition is used in the Day Skipper syllabus but appears to be abandoned in the Coastal Skipper syllabus!

Course to steer

1    Plot the fix on the chart;  mark the destination as a waypoint.

2    Draw the Ground Track from the fix to the waypoint,  and well beyond.

3    Calculate the set and drift of the tide as follows:

3.1    Find the time of HW at the reference port

3.2    Calculate the hour of high water

3.3    Find the tidal hour of the voyage

3.4    Look up the set and drift of the tide from the table of diamonds or the tidal stream atlas

4    Plot the set and drift (the tide vector) from the fix

5    Arc off the boat speed from the end of the tide vector onto the ground track

6    This new line (the water track) is the required heading in °True

7    Convert the water track to °Magnetic

8    Convert to °Compass.   This,  according to the RYA,  is the Course to Steer.

9    Correct for leeway,  to give the helmsman a heading

See Heading and Course.


n   A machine similar to a capstan,  used mostly in the ropewalks.

n   A marine crustacean.

n   'to catch a crab' is when an oarsman dips little or none of his blade into the water when pulling on an oar.   The resulting lack of resistance may cause him to fall backwards off his thwart;  the entire crew becomes unbalanced.

v   To move sideways,  as walking crabs do.   When a vessel is in a strong tide or a river with a strong current she may head more-or-less upstream and allow the tide or current to push her sideways into a berth.   Also known as 'ferry-gliding'.

Crab claw sail

A more or less triangular sail used by the Polynesian islanders in their canoes.   There are two spars,  both of which might be termed yards,  neither of which is a boom.   The triangle has its apex toward the bows;  the base of the triangle (leech of the sail) toward the stern of the canoe.

In use the sail is arranged so that the wind blows equally onto both spars,  parallel with a line from the apex to the middle of the base (leech).   It is also arranged so that the sail has a high angle of attack.

Most other sails work by having a laminar flow of air on both sides of the sail,  while the angle of attack creates a higher speed,  lower pressure,  of air on the leeward side.

A crab claw sail works by creating equal,  mirrored,  spiral vortices of air on the leeward side,  spiralling inward and aft from the spars.

Marchaj has shown that a crab claw sail is more efficient on virtually all points of sail than any other sail shape:  he attributes its efficiency to the creation of vortices rather than laminar flow.

See 'sail'.


n   Another word for vessel.

n   The work done by a skilled person,  a craftsman.


Metal tools,  with two plates which are pushed together by a screw thread,  which are used temporarily to hold two pieces of wood together.


n   A machine for lifting heavy objects and loading and unloading them to and from ships.

Most marinas have a crane,  often mobile,  for lifting boats into and out of the water.

n   A family of large, long-legged, and long-necked birds.


A line from the spritmast to the forestay which helped to steady the spritmast,


adj   A vessel is crank when she has insufficient ballast and might capsize in a wind.

adj   Describing the shape of a handle with two bends.

n  A bar with two bends used as a handle for turning a wheel or small windlass.

Cranse iron

A fitting encircling the outer end of a bowsprit,  to which stays,  bobstays and whisker shrouds are attached.


“Crash stop”

Put the helm down hard (ie,  turn hard to windward),  and secure it.

As the boat comes to the wind,  haul the mainsheet tight,  with the boom on the centre line.

Don’t touch the jib sheets.


The boat will sail in a tight circle while you locate the MOB,  or think.   It will drift with the tide.


Don’t try this with a gaff-rigged boat!


See also Williamson turn,  Anderson turnScharnow turn.


n   A basket,  or pen,  built of stakes and hurdles on the sea shore to trap and contain fish.

v   To move on hands and knees,  as when crossing the foredeck in heavy seas.



A small arm of the sea where a small coastal ship,  or several boats,  might load or unload local cargo.

The Kent,  Essex and Suffolk rivers have very many creeks where,  at one time,  sailing barges,  perhaps owned by the farmer,  would load hay for the horses of London and unload manure (as fertilizer) from the horses of London.

The creeks would often be dug out of the bank by the farmer,  who might also build rudimentary quays.

Goldhanger Creek,  on the North bank of the Blackwater,  is typical.

Lower Halstow Creek,  on the South bank of the Medway,  still has (2017) the quayside,  small boat slipway and ground timbers for sailing barges which still use the creek.

Lower Halstow Creek

Lower Halstow Creek.

The smack in the photo moors in the creek when not cruising.

A sailing barge also uses the creek;  the timbers on which Edith May rests at low water can be seen underwater at right angles to the quay.


The top of a wave;  the highest point.

The crest of a high wave will often,  in a strong wind,  turn over to form a 'white cap' of foam or spume (aerated water).   The crest might be blown downwind as spray (airborne water) or (in gale Force 8) spindrift (spoondrift in Northern England and Scotland).


A collective term for the people on a boat,  including,  perhaps,  the skipper,  but not the guests or paying passengers.

The people who work the boat.



A heavily reinforced rope loop or ring at the corner of a sail to which a line is bent.   Cringles are often reinforced with metal rings.

Cringles at the peak and throat of a sail are used to attach the sail to the yard or gaff.   Those at the tack and clew are used to attach the sail to the boom.   Cringles along the luff and the leech are used,  along with the reefing points,  to draw down the reefs.

The effort of a sail,  the means by which the force of the wind is transferred to the spars and thence to the boat,   passes through the cringles.


A 16th Century device for measuring the height of the sun,  to find the latitude.


The timbers,  attached to the mast,  which support the top.


Cross Jack,  cro'jack

On square rigged ships of the line the course sail was usually omitted from the mizzen mast to allow for the spanker;   the clews of the mizzen topsail were too high to allow the sheets and tacklines to work properly,  so a yard,  the cro'jack yard,  was placed below the mizzen topsail.   The mizzen topsail sheets and tacks were taken to the arms of the cro'jack yard,  thence to the mast and down to the deck.

The braces of the cro'jack yard would be led forward to the mainmast,  and crossed.

Occasionally a crossjack sail was bent to the cro'jack yard,  but it interfered with the spanker and was rarely used.



n   The upward,  or convex,  curvature or camber of a deck:  the centreline is higher than the sheer.   The traditional methods for drawing a crown result in an arc that is not quite circular and not quite parabolic.

n   A form of knot made in the end of a rope.




The ending to a line or rope to form a stopper knot which will not pass through a sheave or small hole.

A wall and crown knot forms a good permanent stopper knot.

Crow’s nest

A mythical lookout point near the top of the mast of a pirate ship.   Known,  in early Medieval times,  as a bowl.   See Top.



v   To sail for pleasure over a period of time stopping at ports along the way.

To sail or motor at a moderate,  comfortable,  speed.

n   A voyage for pleasure,  not racing or profit.


A marine invertebrate with an exoskeleton and many legs,  some of which are jaws or mouthparts.   Examples include crabs,  lobsters,  shrimps and barnacles.


A metal or plastic (rarely wooden) U or Y shaped support,  mounted in the gunwale,  at the sheer, of a small boat,  to transfer the effort of the oars to the boat.

A rowlock.

An oarlock in the USA.


A Cunningham is a device (often a length of line and a purchase) used to tighten the luff of a Bermudian mainsail.   The line is attached to the boom,  or to the mast below the gooseneck,  and passes through an eye in the luff of the mainsail above the tack and down to a cleat on the boom or deck.

A tackline or tack purchase.

A Cunningham lever is an over-centre lever used to tighten the luff of a sail.

A Cunningham Patent Topsail was a "Topsail fitted to a yard that could roll up the sail to form a close reef" or furl.   (Layton)



A flow of water,  as along a river or in a tidal stream or in an ocean current.

A river has a current,  but no tidal stream.

An estuary has tidal streams and often,  at low water,  a current arising from the flow of the river.

Tides and waves often induce strong currents of water around breakwatersgroynes and headlands.   Where these currents,  or eddies,  are predictable they may be charted on a tidal stream atlas.

Ocean currents are relatively discrete streams of moving water unrelated to the tides.


In North America ‘current’ is often synonymous with ‘tidal stream’.


A currant is a small,  dried grape.



That part of a navigation instrument which slides against another,  fixed part,  and which carries a scale.

Cut and run

In order to make a quick getaway,  bypassing the proper procedures,  the anchor rode (and other lashings) is cut.


n   The charge made by a government,  or the practice of making a charge,  against goods brought into the country.

n   A societal habit;  something which society does and has 'always' done.



One of Layton's definitions (paraphrased) is 'a twelve-oared rowing and sailing vessel used by the (British) Royal Navy'.

According to Falconer,  in 1815,  a cutter was "a small vessel . . with one mast and a straight running bowsprit . . rigged much like sloops."  or  "a small boat used by ships of war." usually clinker built ("clinch-work") and "generally rowed with six oars".



Sailing boats are now (early C21) defined by their rig.   In earlier centuries they were defined more by their purpose or size.   As the purpose,  size and rig evolved over decades and centuries names tended to linger,  so that in two different centuries boats with the same type-name might be very different.


A 21st Century sailing cutter has a fore-and-aft mainsail (gaff or Bermudan) and two or more fore-sails,  one abaft the other.   The single mast may be stepped further aft than on a sloop.   The foremost foresail may be set on a stay arising from a bowsprit,  or it may be set flying on its ha’lyard and luff rope.   The aftermost (inner) forestay may be attached part way up the mast,  in which case the mast will have a pair of running backstays.

Alacazam,  Andrew Simpson's cutter


A fast vessel used by officers of,  for example,  the United Kingdom Border Force and the US Coastguard Service.

UKBF cutter


An assembly of timbers forward of the stem,  narrow at the water line and broader above.

It was said to open (or cut)  the water as the ship sailed forward.   In the absence of a deep keel the cutwater would reduce yaw and leeway when close-hauled,  in much the same way as the deep forefoot of a coble.




A cyclone is a mass of inwardly and upwardly spiralling air rotating anti-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere.

Large scale cyclones are centred around regions of low atmospheric pressure;  they are driven by warmer air rising over colder air and by the Coriolis force.

North Atlantic cyclones associated with warm fronts,  cold fronts and occlusions are known as depressions (qv).

A tropical cyclone is a cyclone in the South Pacific or Indian Oceans.

A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and NorthEastern Pacific.

A typhoon is a cyclone in the NorthWestern Pacific.

See Anti-cyclone

John Starkie

October 2020

If you disagree,

or can't find a word

please let me know.