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Glossary of Nautical Terms

When composing a Tech Tip I try to use the proper terminology to eliminate confusion.  Technical writing must be objective and sometimes it is difficult to explain a concept in simple language.  It is also difficult to eliminate colloquialism as it creeps into a language to give it colour.   Aside from that, I sometimes forget what forty years of tinkering around in boats has done for my understanding and language.  It comes easily to me but not to a newbie.   So to help those new to the sport I offer this glossary and welcome all corrections and additions.  Some of the definitions require more than a grain of salt to understand!  Bob Schimmel

  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z




24 Hour Run --

The distance sailed in a 24 hour period.  During the 2008/09 Volvo Ocean Race a world record of 602.66 nautical miles was set by Eriksson 4 in the South Atlantic .  It was previously held by ABN AMRO TWO at 562.96 nautical miles in the Southern Ocean during the 2006/07 Volvo Ocean Race.  Both of these records have since been broken.



Son of a Gun It’s amazing that this phrase has lasted so long.  Back in the day, as you might imagine, sailors were often less than virtuous and every once in a while a “lady friend” of a crewman might give birth to a child on the ship.  A good spot for this sort of thing was between the guns on the gun deck.  Now let’s say this little rascal isn’t claimed by any of the aforementioned sleazy sailors, this little grommet would sometimes be called a “son of a gun”.
Hand over Fist These days this phrase usually refers to making a bunch of money, although it can refer to anything happening fast and in abundance.  It comes from a more literal origin.  Sailors would be tugging at a line as fast as they could, hand over fist, to trim the sheet or to a sail.
A Square Meal People often talk about getting three “square meals” a day.  What the hell is a square meal? It’s actually quite simple.  The wooden plates back in the days of tall ships were square.
Loose Cannon Everyone has known a few people who are "loose cannons," unpredictable and dangerous on some level.  Not surprisingly the term comes from when a ship’s cannon would come loose from it’s lashing.  The big dangerous thing would be sliding or rolling all over the deck making for an uncomfortable effort to get it secured back in its spot.
By and Large Folks say this phrase often to refer to the big picture.  “By and large, ASA is the most awesome organization in existence”… something like that.  This term got started on a sailboat with the word “by” meaning into the wind and “large” meaning off the wind.  So sailors would say: “By and large this ship handles quite nicely.”
Toe the Line Perhaps you’ve been at work and your boss scowled at you and said, “toe the line, or you’re gone”.  If this has happened to you, we are sorry, that sounds like a horrible work environment.  But, if you were wondering about the origins of his demand, it’s an old naval expression that refers to a ship’s crew who would be called to gather and form a line with their toes all touching a given seam (or line) of the deck planking.
Over a Barrel We all know when someone has you “over a barrel” things aren’t going well for you.  This expression is used often today to indicate being severely compromised, but it began in the most literal way.  Sailor crew would sometimes be punished for their misgivings and that involved being tied over a cannon barrel and whipped.  It’s no wonder that one stuck around.  Yikes.
Pipe Down Parents have been screaming “pipe down” to their kids forever, but where does that actually come from?  Apparently, Pipe Down was the last signal from the Bosun’s pipe each day, which meant lights-out, quiet down, time to go to bed.
Feeling Blue How often do you hear people talking about feeling blue or have the blues?  An entire genre of music comes from this phrase.  Who knew it came from the world of sailing? explains the popular phrase comes from a custom that was practiced when a ship lost its captain during a voyage.  The ship would fly blue flags and have a blue band painted along her hull when she returned to port.
A Clean Bill of Health According to this phrase derives from the days when the crew of an ocean going ship might be a little less than hygienic, so they needed to present a certificate, carried on board the ship, attesting to the presence or absence of infectious diseases among the crew and at the port from which it departed.
Above Board: Today the term means someone who is honest and forthright.  In the old days it just meant visible.  The phrase apparently came from a practice by pirates, masquerading as merchantmen, to hide most of their crew behind the bulwarks (“below board?”) until the ship was within striking distance.  By contrast, the crew of a genuine or honest, merchant ship would be visible or “above board.”
As the Crow Flies In everyday language, “As the crow flies” means the shortest distance between two points.  In the old days, it gave you a bearing to land.  Coastal ships in Europe, perhaps back as far as the Viking days, often carried one or more caged crows.  When it was foggy and/or they were unsure of their position, they would let a crow loose, knowing it would fly straight for the nearest land.  The practice of carrying the birds in a cage suspended aloft is also where we get “crow’s nest.”
Bamboozle To get the better of someone through trickery.  Said to originate in the 17th century to describe the Spanish custom of raising false flags to deceive or bamboozle the enemy.
Batten Down, or Batten, the Hatches Make preparations, particularly for some kind of looming disaster.  Aboard cargo ships, battens were long lengths of wood.  When a storm was coming, heavy tarps were thrown over cargo hatch covers and the battens were wedged along the outside edges to ensure the hatches would not leak.

Turn a Blind Eye

Today, if you turn a blind eye, you intentionally ignore something.  In 1801, during the Battle of Copenhagen, then Vice-Admiral Horatio Nelson deliberately put his telescope to his blind eye in order not to see the flag signal from his commander to disengage.  And, being Nelson, he emerged victorious.  What a guy!

By and Large

In the old days, sailing “by” the wind meant sailing as close as possible to the wind (which in those days wasn’t very close).  Sailing “large” meant running or broad reaching.  So aboard a ship “by and large” meant “in most circumstances.”  The meaning ashore has changed a bit to mean, “in general.”
Let the Cat out of the Bag This common phrase, meaning to reveal a secret, had more dire meanings aboard a ship.  The “cat” was the cat o’ nine tails.  A whip with nine ends used to punish recalcitrant sailors.  One can easily imagine that a warning to a misbehaving sailor about letting the cat out of the bag would make him shape up pretty fast.

Cup of Joe

In 1913, Woodrow Wilson appointed Joseph Daniels to be the new Secretary of the Navy.  Among Daniels’ reforms was abolishing alcohol consumption aboard warships (then limited to wine in the officers’ mess).  From then on, the strongest drink aboard a Navy ship was coffee, and it wasn’t long before it got nicknamed “a cup of Joe.” (Does Starbucks know this?)
Devil to Pay The “devil” was a nickname given to the seam where the covering board met the deck planking.  It was so named because it was both the longest seam on the ship, and the most difficult one to get at for periodic caulking.  “Pay” was a type of tar used in caulking.  So “the devil to pay” literally meant “that long, difficult seam that has to be caulked.”  Landsmen mistook “devil” to be literal, and adopted the phrase to mean some unpleasant result from something someone does, as though Satan is exacting retribution.  (This is also where we get the phrase “between the devil and the deep blue sea”).

A           TOP


Towards the stern.


At the side of the vessel or at right angles to it.


Within or on the vessel.

Admirals Cup

Unofficial Grand Prix of yachting, sailed every other year.


Towards the stern, a contraction of abaft.


When the vessel is touching the bottom.


Used in hailing a person or boat.

A-lee, Hard

Tiller pushed leeward, to "come about."


Overhead or above the deck.

America's Cup

Historic yacht race held every three or four years since the 19th century.


In the center of the vessel, in length or breadth


Metal implement, which digs into the ocean bottom, for mooring

Anchor crown

part of the anchor where the arms join the shank

Anchor fluke

The wide triangular plate at the end of the arm.

Anchor light

A white all-around light, for vessel at anchor

Anchor shank

The part connecting the arms to the anchor ring

Anchor sheet

The vessel's largest anchor

Anchor stock

The horizontal rod at the top of the shank, at right angles to the arms

Anchor watch

Person responsible to see if anchor is dragging.

Anchor well

A compartment on the deck of a boat that houses the anchor.

Anchor, bower

large anchor stowed at the bow, ready for use.

Antifouling paint

Paint to inhibit marine growth.


When bow is directly over the anchor, before weighing it.

Apparent Wind

The wind direction felt on the boat as it moves, a combination of the true wind angle, and the change in wind angle created by the boat's movement.

Around Alone Race

Formerly the BOC Challenge, runs every four years.

Aspect ratio

Ratio of mainsail's luff to it's foot.


At right angles to the length of the vessel.


From side to side, across the vessel.


Stop or hold fast, from Italian "basta"-enough


Almost submerged or just exposed out of the water.

B           TOP


A mast support that runs from the top of the mast to the stern. Can be tightened to make the mast bend more, or to tighten the forestay.

Baggy Wrinkle

Rope fastened to stays to prevent sail chafing.

Bale (bail)

To remove water from a boat by a baler.


Weight in the keel of a boat, to add stability (righting moment). The ballast on an Open 60 may include water which can be pumped into tanks on each side of the boat.

Bare poles

Sailing ship in storm, with all canvas down.


Marine crustacean, which attaches to hull's bottom


Thin strips of composite material inserted into a pocket in a sail, to support the curved leech of the sail.


Thin slat, put in sockets at right angles to the leech of a sail to flatten it.

Batten Down

To secure, make water tight.


A boat's greatest width.


The greatest breath of a vessel.

Beam ends

Vessel listed so much the deck beams are vertical.


Timbers running athwartship to support the deck.

Bear away

Turn the bow away from the wind direction.


Angle between the true north and the object


Sailing towards the direction of the wind

Beaufort Scale

A wind scale, 0-12.  Force 12=hurricane (>64).

Bell buoy

A buoy with a bell, rung by the motion of the sea.


Beneath the deck (into the cabin).


Made fast or secured (sail to boom, or rope to rope).


A bed or place to sleep, aboard.

Berth, forepeak

The berth at the bow.

Berth, pilot

An elevated berth, usually above the settee.

Berth, settee

Berth made up on the saloon seats.


The lowest or deepest part inside a boat's hull, It is usually next to the keel.
The turn of a boat's hull, just below the water line.

Bilge water

The water, settling in the bilge.  It is usually a vile, disgusting, foul smelling soup.  Best to wash your hands immediately if you stuck them in it.


The receptacle housing the compass , near the helm.


Strong, vertical post to make fast lines of all types.

Bitter end

The last of an anchor chain or rope end.


A tactical maneuver in which one boat slows a competitor by using her sails to obstruct the competitor's wind.


A frame containing one or more sheaves, (a pulley)

Boatswain (Bosun)

Ship's officer in charge of the rigging.


Chain or rope from end of bowsprit to stem.


heavy short post on dock to secure mooring lines.


Rope sewn to the edge of a sail to strengthen it.


Spar to which a sail's lower edge or foot is attached. The boom is attached to the mast at the gooseneck.


The spar to which the foot of the sail is fastened to.

Boom Gallows

A frame, amidships, to support the boom.

Boom Vang

An attachment to the boom, to prevent it from rising.

Boom Vang or Kicking Strap

Tackle running between the boom and the deck which holds the boom down.


A short spar projecting from the stern, with a sheet block secured, for an overhanging boom.


A band of paint at the water line.

Bosun's chair

A board or canvas seat for hoisting a person aloft.  Way more secure and safer to use a climbing harness.

Bottom paint

Paint applied to the hull below the waterline to prevent marine growth from attaching.


The most forward part of the vessel.


The front of the boat.


A frequently used knot that won't slip or jam.  It is the king of knots as it retains 70% of the strength of the rope.  Other knots retain only 65%.  A spliced eye retains 95% strength.


A strong spar, projected forward from the bow.

Brass Monkey

A pyramid shaped stack of brass cannon balls.  The expression "It's cold enough to freeze the balls off a brass monkey" comes from the times when expanding ice would topple the top cannon ball off the monkey.


Area amidships, from which the vessel is commanded.

Bridge deck

A narrow deck, between cockpit and cabin.

Bright work

Varnished wood and polished brass or chrome.


In a downwind situation, the boat turns uncontrollably and is pushed by the wind on to her side, lying with the mast parallel to the water. usually the boat will right herself but it is a very unnerving motion.


The torpedo shape weight on the bottom of the keel.  A bulb places the ballast at the lowest possible spot on the keel.


Strong vertical partitions in a boat (sometimes water tight).


Extensions of the topsides carried above the decks.


A pointed flag with a yacht club's insignia and colours.


A bulge in the buttocks of the hull.


The rounded part of the boat’s stern section.

By the lee

Running with the mainsail on the windward side.

C           TOP

Cabin sole

The floor of the cabin.


This term encompasses all sails in general.  It comes from the days when sails were made from canvas.


To turn over.  This procedure usually makes you wet.


A machine for hoisting the anchor.


Mainsheet or jib sheet block that runs along a track.


To heel a vessel over on one side (for bottom work).


Timbers running fore and aft between the deck beams.


Hull planks placed edge to edge to give a smooth hull.  The gap between is filled with stuffing to make the hull water tight.

Cast off

To let go the lines securing a vessel to a dock or other.

Cat boat

Sailboat with single mast without shrouds or stays and one sail.


A twin-hulled boat.


Curve of the anchor line between anchor and vessel.


Ripple on the water from a light wind.


The inside lining of the hull up to the deck beams.


A central plate, lowered to prevent leeway.

Centerboard Trunk

The box housing the centerboard

Chain plate

Strip of metal for the attachment of a shroud to keep the mast standing.

Charley Noble

The galley smoke pipe.


A map showing the sea and coast line details.

Chart Datum

The level from which depth on charts are measured.


Metal rail-fitting through which mooring lines are lead.


Short irregular waves caused by currents.


See spinnaker

Claw off

To tack away from a lee shore.


A horned fitting to which lines are made fast.
A fitting which holds a rope against the tension from the sails or rigging.

Cleat, Cam

Two cogs, between which a rope runs in one direction.


The aft lower corner of a sail.
The after lower corner of a mainsail or jib and either lower corner of a spinnaker

Clinker (lapstrake)

Hull plank edges overlapping each other.


Sailing as close to the wind as possible.


Raised sides around the cockpit or hatches to prevent water from the neck running over.


The well in a sailboat, outside the cabin, where the helm is situated.
A recessed area in the deck in which the crew work.


A ladder on a boat or ship.

Companion Way

Stairway leading below the deck.


A navigation instrument that uses the earth's magnetic field to point to the North pole. From this one can deduce all other directions or orient a map to your destination.

Compass Rose

A circle printed on a map showing 360 degrees and the major or cardinal points of direction.  It is usually printed on the chart where no items of interest exist.  While the map is printed oriented to the geographic north pole, the compass rose, printed on the map, is oriented to the magnetic North pole.
History - Originally the compass rose was called the wind rose. It denoted the direction that the 32 winds; 8 major winds, 8 half winds, 16 quarter winds. When drawn as a circle on a map the 32 points resembled a 32 petal rose bloom.  The rose was always associated with Christ and the later the Roman Catholic church. The major winds (pointers) of the wind rose are called Cardinal points. The prime pointer at the top is the Fleur-de-Liz since the rose line went through Paris, France.  Switch the points from winds to magnetic bearings and you have the compass rose we use today. 


The overhanging part of the stern, transom to water.


A frame to hold a vessel upright when hauled out.


A ring sewn into a sail for a line to pass through.


A sloop with two foresails that has the mast stepped almost amidships.

D           TOP

Dagger board

Center board that lowers vertically in a trunk.


Hoists for lifting boats from the water.

Dead ahead

Directly forward.

Dead Reckoning (DR)

Position calculated by direction and distance sailed.
The calculation of a boat's position based on course and direction run.


Barely floating, heavy water-logged log.


Flooring of a vessel, supported by the deck beams.

Deck Beams

Timbers running athwartship the top of the hull, supporting the deck.


Failure of the bond between either of the hull's outer and inner skins, and the  'sandwich' spacing material in between -- allowing either of the two outer layers to become unstuck from the foam centre.


Small boat towed by a pleasure craft.


The weight of water displaced by a vessel.


Canvas screen or similar protection for the cockpit.

Dog watch

The two hour periods of duty between 1600 and 2000.


Several piles banded together in a harbour.


Deck vent that prevents water from coming below.


Vessel with a rounded stern and bow.

Down haul

The line used to haul down a sail (or tighten the luff).


The direction a balloon would blow in the wind, if you let it go.


Depth of water necessary to float a vessel.


A sea anchor, usually made of canvas.

E           TOP


A line used to secure the corner of a sail to a spar.


To take pressure off (as in easing the sheet).


The receding tide.  To run out or run low.


A small local current, often flowing in a different direction to the main current around piers or points of land.  Eight Bells Struck at the beginning and end of each four hour watch, i.e.  at 04:00, 08:00, and 12:00 and 24:00.

Elapsed Time

The yacht's elapsed time in days, hours and minutes from the start of the leg to her finish of that leg.


An alternative name for a knee.  A timber or steel member that units two structural members.  Sometimes called a hook.


Corrosion of metal by galvanic action.


To put on board or go on board.


The national flag worn by ships of a nation.  Also a naval rank.

Even Keel

A vessel is said to be on even keel when it does not heel to either side, or fore and aft.

Eye Splice

A loop or eye made in the end of a rope or wire by turning the end back and splicing it through the standing part, usually around a thimble.

F           TOP


A metal channel for a rope; used to reduce friction.

Fend Off

The operation of bearing a vessel off by a spar, boat hook, or fender in order to prevent violent contact when coming alongside.


A side bumper, to protect the boat from docks or boats.


rails on tables or stoves that prevent spillage.


Carved head or figure at the bow of a sail boat.

Finish Time

The GMT date and time the yacht finished the leg.

Fisherman's Reef

Dropping the gaff peak, to reduce sail.


Coiling a rope; each complete turn is a flake.


Inclination outwards of the topsides (as at the bow).  Also an incendiary device used as an attractant in an emergency.


Floating debris.


The lower edge of a sail.
The bottom edge of a sail.


Any sail used between the mast and the forestay.


Forward item of standing rigging that supports the mast.
A mast support that runs from the top of the mast to the bow. Can be tightened to make the mast bend more, or to tighten the backstay.


To sink by filling with water.

Fractional Rig

The forestay is attached a 'fraction' below the top of the mast -- usually 7/8th or 5/6th of the height of the rig.


The skeleton of the hull.


The ribs or timbers of the hull frame.


The height of the deck from the waterline


To roll up the sail and secure it to the boom

G           TOP


A boat with the head of it's mainsail bent to a spar (called a gaff).


The cooking area of the ship.


Includes equipment, fittings, spars, ropes and canvas.

Genniker (Gennaker)

Cross between a genoa and a spinnaker, a foresail used for reaching.

Genoa (Genny)

A large foresail used for sailing upwind, it overlaps the mainsail.


Devices that allow gear such as the compass or stove to swing and stay horizontal when the boat heels.


The fitting attaching the boom to the mast.

Grab rails

Handrails, inside the cabin, to steady oneself on.

Granny bars

Rail supports on either side of the mast.

Grapple grommet

The piece into which the grapple fits.


Metal rings that engage the pintles of the rudder.


Rubber footwear used to keep feet dry.  Also called deck boots

Gunk hole

A small area of Coal Harbour at low tide.

Gunwale (gun'l)

The top plank of the top sides.


Ropes or wires used to steady a spar or boat.


Turning the boat so that the stern passes through the wind, and the boat changes from port tack to starboard, or vice versa.

H           TOP


Lines by which sails are hoisted.
Line that holds a sail up.


Rail on the cabin deck one grabs to steady oneself.

Harden Sheets

Pull in the sails.


An opening in the deck, for passage up and down.

Hawse pipe

A pipe through the bow for the anchor chain (also called a Navel pipe).


The boat's toilet.  It was named the head, because in the days of Captain George Vancouver, it was located at the bow or the head of the ship, directly over the water!  This was a convenient location for the drainage tube to discharge directly into the water.  It was “self cleaning” when under way out in the open ocean, due to the action of the bow wave, but in port it was a stinking mess.  Hence the reason for approaching a vessel at the stern.  The Captain generally used a bucket in his cabin for performing his duties while in harbour.


Fitting at the head of a sail to receive the halyard.

Head stay

The stay from the masthead forward.


Pointing into the wind, with a back winded shortened foresail and the tiller lashed to leeward.


To careen or list to one side.


Relates to the tiller or the steerage.

Helm, lee

When tiller must be to leeward to stay on course.

Helm, weather

When tiller must be to windward to stay on course.


The person steering.


To raise aloft


Slang for anchor.


The point where the shrouds attach to the top of the mast.


The body of the boat, excluding the cabin and interior.

Hull Speed

A boat's theoretical maximum speed determined by multiplying the square root of her waterline length by 1.34.

I           TOP

In irons

Pointing directly into the wind, with no way on and unable to tack to either side.


Towards midship, away from the hull side.


The International Offshore Rule, used as a means measuring sailboats competing in offshore races.

Irish pennant

A loose end hanging anywhere aloft.


Tool used in caulking deck and hull seams in wooden boats.

Iron mike

An old term for an autopilot.  Named after the design of the first autopilots which were cast in an iron case and considered best installed under the cockpit.

Iron topsail

Old term for an engine.

Iron wind

Present term for an engine.


The International Yacht Racing Union, which monitors world sailboat racing.

J           TOP


The lines that run the length of the boat to which you attach your harness.


A wire stretched tight between two ships to permit transferring stores and personnel.  On square riggers, it is the iron bar on the top yard to which sailors are lashed.


Slang term for a Genoa sail (usually spelled "Genny").


The joint used to bring lapstrake planking from overlapping to flush at the stern and the stem.


A triangular sail set as the forward headsail used for upwind work.


A small sail set aft on a yawl or ketch.


The carpentry or woodwork aboard a boat

Jury rig

A makeshift, temporary rig.
Emergency rigging with available gear, usually involves a broken or missing mast.

K           TOP

Kedge (anchor)

A light or small anchor.


Using a kedge anchor to warp off a shoal or lee shore


Central bottom of the hull running fore and aft.  Usually a ballasted appendage projecting below the boat that keeps it from capsizing, and also supplies the hydrodynamic lateral force that enables the boat to sail upwind.


Timber lying fore and aft, above the main keel.


Two masted sailboat, with mizzen mast stepped forward of the rudder post.


Manmade fiber which is used to make sails and hulls. In sails it retains it shape better and is lighter than Dacron, but is more expensive.

King spoke

Uppermost wheel spoke, when rudder is amidships.


Pieces attaching the beams to the timbers or ribs (elbow or hook).


A measure of speed, 1 nautical mile (6080 ft) per hour.  (One minute of arc of the equator, i.e.  1/60 of a degree of longitude, 6068.4 feet.)

-   A minute of latitude = 1 degree of latitude.

-   1 second of latitude = 1/60 of a minute of latitude.

-   Speed through the water is sometimes expressed in knots (i.e.: knots/hour). 1 nautical mile per hour = 1 knot.

- 1 nautical mile per hour.

L           TOP


A rope tied to anything to secure it, e.g.  knife.

Lapstrake (Clinker)

Overlapping plank edges on the hull.


To sail a course that will clear an object or marker such as a body of land.


A small compartment at the stern of the cockpit for used for stowage.


The side of the boat from which the wind does not blow.

Lee cloth

Heavy cloth fixed to berth, to prevent falling out.

Lee helm

When tiller must be to leeward to stay on course.

Lee shore

The shore upon which the wind is blowing.


The after border of a sail.
Trailing edge of a sail. Also, the curve of a sail.


The downwind side of an object.


The line stretched between the stanchions.
Cables which are held in place by stanchions, and go around the boat to prevent people falling overboard.


A wind shift allowing the helmsman to head up, or alter course to windward or the crew to ease sheets.

Limber holes

Small holes in the lowest part of the ribs (frames), to allow bilge water to flow through.


A nautical term for ropes.


The inclination of a vessel to one side.


A box or closet, aboard a boat, to stow things.

Locker, hanging

A tall closet, aboard a boat, to stow things


Device for measuring a vessel's speed through the water


A record of events on board, e.g.  navigation.

Longitude & the prime meridian

On a globe a rose line, also called a meridian or longitude, is an imaginary line drawn from pole to pole and divides the globe East to West in 360 increments called degrees. 
- The Rose Line, 00 Longitude, is the reference line from which all other lines are measured.  Today it is called the Prime Meridian and goes through Greenwich, England, hence the term "Greenwich Mean Time" (GMT). The line was established in 1888.  
History - The world's first 0 longitude passed through Paris, France and the church of Saint Sulpice.  The church is built with a brass line in the floor as a memorial to the world's first prime meridian.  The brass line terminates in an obelisk at the North end of the church.  

- The "shadow of the Sun" travels across the Earth's surface at the equator at a rate of one line of longitude per 4 minutes. At 49o N latitude the speed is 121 kilometers per minute.


A sail without its foot secured to a boom.


A greenhorn or clumsy sailor aboard a boat.


The fore and aft line of a compass.  (generally used as the direction of travel)


The forward edge of a mainsail or jib and the windward edge of a spinnaker.


Bubbling or flapping of a sail when it is not trimmed enough or is being back winded by another sail or when the course sailed is too close to the wind.  Also called pinching.

M           TOP


The line that is used to adjust the mainsail's angle to the wind.

Make fast

To secure or tie up.


A buoy used in a race course.


The stick on a sail boat trying to drive itself through the hull.

Mast butt

Slang for the lower end of the mast.

Mast Heel

The foot of the mast.

Mast partners

Fittings at the mast hole for mast support.  Associated with a keel stepped mast.

Mast rake

The angle of the mast from the vertical.  Usually aft angle.

Mast step

Where the mast heel fits, on the keel or deck.

Mast tangs

Metal plates attached to the mast to which rigging is made fast.

Mast truck

Flat circular piece at the mast head.


The top of the mast.

Masthead Rig

The shrouds are attached to the 'masthead' -- the top of the mast.

Mast hole

Hole in the deck, through which the mast goes on a keel stepped mast.

Matthew Walker

A stopper knot.  One of the few knots named after its creator.


A distress call on the marine radio.


The after most mast of a ketch or yawl.


The moon revolves around the earth once every 28 days; altering the gravitational force and creating tides.  Also that shiny rock in the night sky that so many couples make a wish at!


When a vessel is made fast by mooring lines.


A site for a vessel to moor (a buoy or dock).

Mooring Pennant

A short line to tie a vessel to a mooring (a buoy or dock).

N           TOP

Nautical Almanac

An annual publication listing information needed for celestial navigation.  Nautical Mile One minute of arc of the equator, i.e.  1/60 of a degree of longitude, 6068.4 feet.

Nautical Mile

The unit of geographical distance used on salt-water charts where 1 nautical mile = 6076 feet or 1.15 statute miles. Therefore 1 statute mile = 0.87 nautical mile.

Naval Architect

One who designs and assesses all aspects of all types of vessels.

Navel Pipe

Conduit for the anchor chain to go below deck (often mistakenly called the "hawse" pipe aboard pleasure boats, which is an all together different hole in some decks).

Navigate, Chart

The vertical scale on nautical charts is shown in knots (including metric charts). The major divisions are minutes of latitude and the subdivisions are seconds of latitude or knots. - The vertical scale is used to measure distance on a chart, which can also be used to calculate time and speed. Simply set the points of the divider on the 2 locations in question. Then transfer this length to the right scale to determine distance or to the log scale to determine speed.

Navigate, Latitude

Lines of latitude go east and west around the globe as concentric circles.

-   The North pole is 90o north latitude.

-   The Arctic Circle is 66.5o north latitude.

-   The Canadian/American border is 49o north latitude.

-   The Tropic of Cancer is 23.5o north latitude.

-   The Equator is 0o latitude.

-   The Tropic of Capricorn is 23.5o south latitude.

-   The Antarctic Circle is 66.5o south latitude.

-   South pole is 90o south latitude.

Navigate, Time

The lines of longitude are also grouped into 24 time zones, (i.e.: 24 hours per rotation of the Earth).  A time zone is defined as the number of degrees that the sun travels across the Earth in one hour.

-   There are 15o of longitude per time zone. 

-   The time reference is at 0o Longitude, the Prime Meridian, and is called GMT or ZULU time.

-   The time in another zone, e.g.: Mountain Standard, is also referred to as + 12 hours GMT or 12 hours Zulu time.

-   The International Date line is located at 180o longitude. This is the line of longitude that was chosen where a "new day" begins on earth.  The 180o longitude line creates the least interruption with people's daily routines simply because nobody lives along it.

-   Daylight Saving time was introduced to save energy by altering man's clock closer to the Sun's time...  Generally the clock is advanced 1 hour in Spring and retarded 1 hour in Fall. Sometimes the difference is 2 hours. Other zones find it convenient not to change. Viva La difference.  Frankly I wish it was left alone on standard time to make navigation easier.  You might think about this the next time you fly across the pond with bleary eyes.


Piloting a vessel from one place to another.  The term is also applied to moving across land.


When the tide is not high enough to float a boat.


A retaining device on a gaff rig that keeps the gaff or boom jaws in place around he mast.  Also known as a parrel.


The vertical luff laced to the mast on the staysail of a brigantine or a barque.

O           TOP

Off the wind

Sailing away from the wind, also downwind, reaching or running.

P           TOP


Removing a sail or changing from one spinnaker to another.

Pennant Small flag usually flow on the mast head.


A boat pitches when the front and back move up and down about the transverse centre.


A boat planes when she sails over her own bow wave, so that only a small section of the hull is in the water. This in turn allows the boat to go faster than the theoretical maximum hull speed.

Polar Table

The name for the database that holds all the information on what speed the boat will sail at different angles to the wind. Crucial for maintaining performance when there are no other boats in sight, and for making good navigational decisions.


The left half of the boat when facing forward.

Port tack

Sailing with the wind blowing onto the port side, and the mainsail on the starboard side.

Q           TOP


Quarter or aft side of the hull.  As in "the wind is blowing over the starboard quarter".

R           TOP


Same as the gunwale, the edge between the hull and the deck.


Sailing with the apparent wind between 45 degrees and 135 degrees to the boat.

Reef, to

To decrease a sail's size.

Rhumb line

The most direct course between two points.

Rigging (standing)

The gear used to support and adjust the mast; Shrouds, forestay, backstay, turnbuckle.  There is lots more but this will get you started.

Rigging (running)

The gear used to support and adjust the sails; Sheets, halyard, down haul.


Solid steel wire that replaces cables in the rigging of large boats.

Roller furling

A device to mechanically furl a sail, usually used for foresails.


The hull's sideways movement, about the fore-and-aft axis.

Running Backstay

Two adjustable stays that support the mast, one on the port side and one on the starboard. Running from the hounds, to the rear of the boat. The stay will have to be eased on the leeward side to let the mainsail out.

Running Rigging

All moving rods and lines that support and control the mast and sails.

S           TOP


Each boat's scheduled position report. From schedule, when the boats would have to radio in to compile the daily schedule.

Settee A bench or seat inside of a cabin.  It is usually along the side of a cabin.


A line that controls sails.


Cable or rod that supports the mast, from the chain plates at deck level on the port and starboard side, to the hounds just below the top of the mast.


A basic term for a mast, boom or yard.

Speed Made Good (SMG)

A boat's speed as measured by her progress relative to land, factoring in her speed through the water and current.


A large half spherical shaped nylon sail flown from the mast head in front of the forestay and generally used for downwind sailing.  Also known as a kite. It pulls like a horse. 
Large light ballooning sails, that are only attached to the spars at the corners. They are used when running or reaching, sailing downwind.

Stanchion Vertical supports that hold the lifelines in place around the boat.

Standing Rigging

The non-moving rods and lines that support the mast and sails.


The right half of the boat when facing forward.

Starboard tack

Sailing with the wind blowing onto the starboard side, and the mainsail on the port side.


The rear of the boat.

T           TOP


To pass or turn the bow of a sail boat through the eye of the wind.  The wind then blows over the other bow.  A vessel is said to be on a starboard tack when the wind is blowing over the starboard bow.
Turning the boat so that the bow passes through the wind while upwind of the stern, and the boat changes from port tack to starboard, or vice versa.

Toe Rail

Aluminum extrusion bolted along the gunnels of a fiberglass sailboat.  It is used as part of the hull to deck joint and doubles as a place to attach running rigging to, i.e.: snatch blocks or fenders.


The flat rear end of a boat, the upper part of which tends to lean forward on modern racers.


Track or bar on which the bottom part of the mainsheet runs across the boat.


To adjust the sail to make it the right shape and angle to the wind.


To break loose.

True Wind

The actual direction of the wind. Can only be directly measured on board when the boat is stationary. Otherwise, it is calculated by the instrument system.


The threaded device at the bottom of each shroud, forestay or backstay that is used to tighten these wires.  It consists of a toggle at the bottom to connect to the deck, a barrel (open or closed) in the middle to adjust the length, and a jaw or eye at the top to connect to the wire. 

U           TOP


Toward the direction from which the wind blows.

V           TOP

Velocity Made Good (VMG)

The average speed of a yacht since the start of the Race, if the yacht had sailed the shortest route.

W           TOP


The working teams into which the crew are divided. To be on watch means to be working. Free time is referred to as the free watch, or off-watch.

Watch Leader/Captain

The person in charge of a watch.




MOON - The moon revolves around the earth approximately once every 28 days; modulating the earth’s gravitational force and creating tides.

WEATHER - The Tropic of Cancer is located along 23.7o North latitude and the Tropic of Capricorn is along 23.7o South latitude. These are the Northern and Southern limits of where the sun’s rays strike the earth's surface at 90o to the ground; creating permanent tropical weather between them.

The Arctic Circle is located along 66.3o North latitude and the Antarctic Circle is along 66.3o South latitude.  These are the Northern and Southern limits where the sun's rays strike the earth’s surface at 0o to the ground; creating 24 hour daylight in Summer and 24 hour darkness in Winter above 67.5o

  • The equinox occurs when the Sun is directly over the equator. On this day there are 12 hours of light and 12 hours of darkness over the Earth.

  • Spring in the northern hemisphere starts on May 23, the day after the equinox. 

  • Fall in the northern hemisphere starts on September 23, the day after the equinox. 

  • Daylight saving time is a man made phenomenon to supposedly save energy and confuses many navigators who fail to subtract or add an hour (depending on the time of year) to their calculations.

  • A high pressure weather area and the water in a toilet bowl both rotate clockwise in the Northern hemisphere and counter clockwise in the Southern hemisphere. This is important to know since you can use this information to tell if a storm is coming or going, judging from the direction of the wind. You may therefore set an appropriate course for safety.

  • The leading edge of a storm is generally more severe than the trailing edge. The eye is generally quieter than either edge.

WEST Wood Epoxy Saturation Technique.  A technique developed by the Gougeon brothers of Michigan that uses wood as the fiber and epoxy as the resin to hold it all together.  This process strengthens and stabilizes wood against rot.  It is used to manufacture anything (especially boats) that requires great strength and vibration absorption. 

Winch Pedestal

Upright winch drive mechanism with two handles -- increases purchasing power.

X           TOP


Some day something will be named with a X.

Y           TOP

Yard arm

A cross brace used to support a square sail as on a clipper ship or barque.


To sail a wildly erratic course.  This generally the motion that makes you violently sick at sea.



Some day something will be named with a Z.

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