aback
Behind of the Sails pressed against the mast when the wind is on the wrong, inefficient side. Deliberately sailing aback is useful in close quarters sailing, such as when leaving a jetty or mooring
abaft
Toward the rear (stern) of the boat, behind, or anything located aft of something else.
abaft the beam
behind a perpendicular line extending out from the middle of the boat
abeam
At a right angle to the length of the boat.
aboard
on or within the boat.
about
Across the wind in relation to the bow. When a sailboat tacks into the wind to bring it from one side to the other, she is said to go about.
above deck
On the deck of the boat, not aloft
abreast
Side by side, normally referring to ships or boats that are aligned like that.
accidental jibe
An accidental jibe happens when the boat is steered or the wind shifts such that the stern of the boat accidentally passes through the eye of the wind. This causes that main boom to swing violently to the other side of the boat. Without proper preparation when jibing, the force of the boom's motion can be destructive, injuring the crew and damaging equipment. In strong winds and on large boats this force can dismast the boat and seriously injure crew members hit by the boom. Sometimes a preventer is used to reduce the possibility of an accidental jibe.
aclinic line
The imaginary line where the compass needle does not dip due to the earth's magnetism
admeasure
Formal measurement of a boat for documentation.
admiralty anchor
An anchor which can be folded for easy stowage. The shank and arms do not move, but the stock moves up to the right angles to the arms.
admiralty law
The "law of the sea".
admiralty sweep
A large cautious turm made to approach a gangway or to come alongside a vessel or jetty in a boat
adrift
Floating free with the currents and tide, not under control, floating without any means of propulsion or mooring.
aerodynamic
Having a shape that that is not adversely affected by wind flowing past it.
aft
Toward the stern of the boat.
after bow spring line
A mooring line fixed to the bow of the boat and leading aft where it is attached to the dock. This prevents the boat from moving forward in its berth. Its opposite, the forward quarter spring line, is used to keep the boat from moving aft in its berth.
afterpart
The part of a boat aft of the beam.
age of the tide
The interval between full moon or change of the moon and the highest high tide
agonic line
The line around the earth where there is no magnetic deviation between magnetic north (as measured by a compass) and true north.
aground
When a boat is stranded on the shore, or on the bottom of the body of water, it is said to have run aground.
ahead
In a forward direction.
ahull
Lying ahull- When all sails are lowered, usually in open water.
aid to navigation
Any fixed object that a navigator may use to find his position, such as permanent land or sea markers, buoys, radio beacons, and lighthouses.
akas
Lateral struts that attach outrigger hulls to a trimaran or proa.
aladdin cleat
a cleat that attaches to the backstay over the cockpit, usually used for hanging a lantern
alee
Away from the direction of the wind. Opposite of windward. To the leeward side (downwind).
all standing
To have all sails flying when running before the wind.
aloft
Above the boat, in its rigging.
altazimuth
An instrument for establishing the altitude and asimuth of the stars and planets
ama, amas
The outrigger hull(s) of a proa, or trimaran.
amidships
In the center of the boat.
amplitude
In navigation, the arc of the horizon between east and a body when it is rising, and west and a body when it is setting
anchor
A heavy metal object designed such that its weight and shape will help to hold a boat in its position when lowered to the sea bottom on a rode or chain. See kedge, lightweight, mushroom, and plow anchors. The act of using an anchor.
anchor bell
A bell required to be rung at certain times when at anchor during fog, according to the navigation rules.
anchor bend
A type of knot used to fasten an anchor to its line.
anchor cable
Chain or rope that connects the anchor with the vessel
anchor chain
A chain attached to the anchor. The chain acts partially as a weight to keep the anchor lying next to the ground so that it can dig in better. Chain is also not damaged as much as line when lying on rocks. The weight of the chain also helps to absorb changes in the boat's position due to waves.
anchor light
A white light, usually on the masthead, visible from all directions, used when anchored.
anchor locker
A locker used to store the anchor rode and anchor.
anchor rode
The line or chain attached to the anchor and secured to the boat.
anchor roller
Also called bow roller. A fitting with a small wheel that allows the anchor and chain to roll over when dropping or raising the anchor. Some anchor rollers also have a provision to store the anchor as well.
anchor warp
see anchor cable
anchor watch
A watch kept when the boat is at anchor in case the anchor starts to drag.
anchor windlass
A mechanism that is used in yachts to raise an anchor through the warp around a drum
anchorage
A place where a boat anchors, usually an established and marked area.
anemometer
An instrument that measures the velocity of the wind.
aneroid barometer
A mechanical barometer used to measure air pressure for warnings of changing weather.
angle of attack
The angle of a sail in relation to the direction of the wind.
angle of heel
The degree of list a vessel has when underway.
annual variation
The amount of by which variation changes up or down each year in a particular area. The annual increase or decrese is printed in the compass roses on each chart and may make a significant difference over a number of years
anticlone
An area where the barometric pressure is high, usally indicating light, variable winds and fine weather
anticyclone
High-pressure area, a meteorology term
antifouling Paint
Paint with toxic chemicals that is applied to the hull to reduce or prevent marine growth
antitrade
Wind that blows in the opposite direction from trade wind in an area where trade wind would normally be expected to occur
aport
To the port side of the boat.
apparent wind
The combination of the true wind and the wind caused by the boat's own speed. This is the wind felt on the boat, as well as the one shown by the telltales.
arc of visibility
The sectors marked on a chart and showing where a light is visible from the sea
ashore
To be on or to go to the shore.
aspect ratio
Concerns sails - the ratio of height to the length. A narrow but tall sail has a high aspect ratio, and a wide but shorter sail has a low aspect ratio.
astern
Toward the stern of a vessel, or behind the boat.
astrolabe
An old navigational device for checking the angle of stars in the skies
at the dip
A flag hoisted half way up a flagpole. Also see "close up".
athwart, athwartships
Lying along the ship's width, at right angles to the vessels centerline.
atmospheric pressure
Also called barometric pressure. The weight of the atmosphere, an average of 1013.2 millibars or 29.2 inches of mercury at sea level. Measuring the changes in atmospheric pressure can help predict weather.
autopilot
A device used to steer a boat automatically, usually electrical, hydraulic or mechanical in nature. A similar mechanism called self steering gear may also be used on a sailing vessel.
autopilot
A device - may be electronic or mechanical - used for keeping the boat on course without having to steer it. It uses a compass, and is attached to the boat's steering mechanism.
auxiliary
A second method of propelling a vessel. On a sailboat this could be a engine.
avast
A command to stop or cease what one is doing.
awash
Water washing over. A boat when almost submerged.
aweigh
The position of anchor as it is raised clear of the bottom.
back
To force a sail out against the wind. The wind backs when it shifts in a counterclockwise direction.
back a sail
To hold a sail in such a way, that the wind will fill it from the opposite to usual side. This maneuver is used to slow down the boat (as if applying brakes), or to force a boat to tack when in irons.
backing (wind)
The changing of the wind direction, opposite of veering. Clockwise in the southern hemisphere, counter-clockwise in the northern hemisphere.
backsplice
A method of weaving the end of a rope to keep it from unraveling.
backstay
A mast support that runs from the top of the mast to the stern of the yacht; it may be adjustable in order to bend the mast backward or to increase tension on the forestay.
backwind
A wind that shifts in a counterclockwise direction. To loosen the trim of a mainsail so that it flaps in order to reduce heeling.
backwinded
When the wind pushes on the wrong side of the sail, causing it to be pushed away from the wind. If the lines holding the sail in place are not released, the boat could become hard to control and heel excessively.
baggywrinkle
Clumps of frayed rope that protect the sails from chafing against the lines.
bail
To remove water from a boat, as with a bucket or a pump.
bale
A fitting on the end of a spar, such as the boom, to which a line may be led.
ballast
A weight at the bottom of the boat to help keep it stable. Ballast can be place inside the hull of the boat or externally in a keel.
ballast weight
usually metal, placed low in a boat to provide stability.
balloon jib
Sail used on a reach; larger and fuller than a genoa
bar
A region of shallow water usually made of sand or mud, usually running parallel to the shore. Bars are caused by wave and current action, and may not be shown on a chart
barber hauler
A line attached to the jib or jib sheet, used to adjust the angle of sheeting by pulling the sheet toward the centerline of the boat.
bare poles
In a very strong wind it is possible to be propelled by the force of the wind on only the mast and the boom. To sail in such a way is called "bare poles".
bareboating:
Renting a boat with no crew, generally for vacations
barge
A long vessel with a flat bottom used to carry freight on rivers. Barges are usually not powered, being pushed or towed by a tugboat instead.
barograph
An instrument used to keep a record of atmospheric pressure, such as on a paper drum.
barometer
An instrument used to measure atmospheric pressure, usually measured in inches of mercury or millibars. Inches of mercury are used because some barometers use the height of mercury in a sealed tube as a measuring device.
barometric pressure
Atmospheric pressure as measured by a barometer.
barque, barquentine
A sailing ship with three to five masts, all square-rigged except the after mast (last), which is fore-and-aft rigged.
batten
A thin strip of hard material, such as wood or plastic. Battens are sewn in or placed in batten pockets on a sail to stiffen it to more preferred shape. They are also used to secure hatches.
batten down
Also batten the hatches. To put away all loose objects on the ship and to close all openings, such as ports and hatches, in preparation for heavy weather. Hatches used to be secured with battens.
batten pockets
Pockets in a sail where battens can be placed to stiffen the sail.
batten the hatches
Also batten down. To put away all loose objects on the ship and to close all openings, such as ports and hatches, in preparation for heavy weather. Hatches used to be secured with battens.
bay
An enclosed body of water with a wide mouth leading to the sea.
beachcomber
A sailor who does not want to work that loafs around ports. -To salvage goods found washed up on shores.
beacon
A light, or other naviga-tion aid, usually on land, to warn boats of danger or obstruction.
beam
The widest part of a boat. Wooden struts running acorss the width of the boat to support the deck.
beam reach
Sailing on a point of sail such that the apparent wind is coming from the beam (side) of the boat at about a 90° angle. A beam reach is usually the fastest point of sail. A beam reach is a point of sail between a broad reach and a close reach.
beam sea
Waves running at right angles to the boat's course.
beam wind
A wind that blows at at right angles to a boat's course.
bear away, bear off
To fall off. A boat falls off the wind when it points its bow further from the eye of the wind. The opposite of heading up.
bearing
The direction of an object from the observer. "The lighthouse is at a bearing of 90 degrees."
bearing
A direction an object is relative to the observer (based on the compass heading).
bearing away
To turn a vessel away from the wind
beat (also) beating
To sail towards the wind by making a series of tacks. -Sailing close hauled.
Beaufort wind scale
A method of measuring the severity of the force of wind, named after Admiral Beaufort who created the system. 0 is no wind, whereas 12 would be a hurricane.
becket
A loop at the end of a line.
bedding compound
A material used to join two objects completely. Usually used to create a water tight or very secure joint.
before the wind
Sailing with the wind from astern, in the same direction the wind is blowing,
belay
To temporarily secure a line to a cleat, or as a command "disregard the last order"
belaying pin
A wood pin fitted into racks, around which lines can be belayed or secured.
bell bouy
A buoy with a bell that sounds when the buoy is moved by the waves.
below
Beneath the deck.
bend
A type of knot used to connect a line to a spar or another line. Also the act of using such a knot.
bend on
To attach a sail and prepare it for use.
bermuda rig
The most common sail plan, sails are tall triangular shape.
bermuda sloop
The most “classic” rig with a triangular mainsail and a jib
berth
A place for a person to sleep. A place where a ship can be secured. A safe distance from something as in "giving it a wide berth:.
bight
A bend in the shoreline. The part of a rope used for making knots.
bilge
The lowest part of the interior of the boat where water collects.
bilge board
Centerboard structure to decrease sideways drift
bilge pump
A pump to remove water from the bottom of the hull
bimini
A cover used to shelter the cockpit from the sun.
binnacle
The mount for the compass, usually located on the wheel's pedestal.
binocular
A pair of small telescopes, one for each eye, used to magnify distant objects.
bitt
A sturdy post mounted on the bow or stern to which anchor or mooring lines may be attached.
bitter end
The end of a line. Also the end of the anchor rode attached to the boat.
block
One or more wheels with grooves in them (pulleys) designed to carry a line and change the direction of its travel. A housing around the wheel allows the block to be connected to a spar, or another line. Lines used with a block are known as tackle.
block and tackle
A combination of one or more blocks and the associated tackle necessary to give a mechanical advantage. Useful for lifting heavy loads.
bluewater sailing
open ocean sailing, as opposed to being in a lake or sound
board boat
A small boat, usually mono rig. May have a shallow cockpit well. Typically has almost no freeboard.
boarding ladder
A ladder used to board the vessel. Boarding ladders may be designed to be useful from either the water or a dock and are usually stowed when not in use.
boarding wave
A wave that breaks over the deck of the boat.
boat
A small vessel used to travel on the water, powered by either wind, power or oars. Also any small vessel carried on a larger ship.
boat hook
A pole with an attached hook at the end, used for either retrieving objects or fending them off.
boatswain
Also bosun, bos'n, bo's'n, and bo'sun, all of which are pronounced bosun. A crew member responsible for keeping the hull, rigging and sails in repair.
bobstay
Wire Stay underneath the bowsprit; helps to counteract the upward pull exerted by the forestay.
bollard
A large pillar, usually made of concrete or steel, to which a boat's mooring lines can by tied.
bolt rope
The line sewn into the edge of a sail.
bone in her teeth
sailing well underway such that spray is thrown out at the stem of the boat
boom
A pole securing the bottom of a sail, allowing more control of the position of a sail.
boom crutch
Supporting structure for the boom, stabilizes it when the boat is anchored
boom vang
Any system used to hold the boom down. This is useful for maintaining proper sail shape, particularly when running or on a broad reach.
boomkin (bumpkin)
Short spar extending aft from the transom. Used to anchor the backstay or the sheets from the mizzen on a yawl or ketch.
boot stripe
a different color strip of paint at the waterline
boot top
A painted stripe that indicates the waterline.
bosun
Also boatswain, bos'n, bo's'n, and bo'sun, all of which are pronounced bosun. A crew member responsible for keeping the hull, rigging and sails in repair.
bosun's chair
A chair traditionally made from a plank and rope, used to hoist workers aloft to maintain the rigging.
bosun's locker
A locker where tools for maintaining the deck, rigging and sails are kept.
bottlescrew
A fitting to control the tension on the forestay
bow
The front of the boat.
bow & beam bearings
A set of bearings taken from an object with a known position, such as a landmark, to determine the ship's location. A type of running fix.
bow fitting
Fitting to which the jib is attached
bowline
A knot used to make a loop in a line. Easily untied, it is simple and strong. The bowline is used to tie sheets to sails. A mooring line at the bow.
bowditch
A reference book named after the original author, Nathaniel Bowditch. Updated versions contain tables and other information useful for navigation.
bower anchor
Main anchor of a boat
bowman
The crewmember in charge of sail changes and keeping a lookout on the bow at the start.
bowsprit
A pole extending from the bow of a boat. The bowsprit is used to attach the headstay forward of the front of the boat's deck. This allows added sail area for the head sail.
brace
A guy. A line used to control the movement of the object at the other end, such as a spar.
braided line
A method of making lines that allows for greater strength and durability when using modern materials.
brale
Partially furling sails to lessen wind resistance or partially unfurling sails to make them ready for instant use. On a square sail this is accomplished with leech and clew lines. See "Scandalize"
breakers
Waves that have entered a shallow water, and built up on height. By doing this they "break" at the crest producing a curled up formation.
breaking seas
With sufficiently strong wind, large waves can form crests even in deep water, causing the wave tops to tumble forward over the waves.
breakwater
A structure build to improve a harbor by sheltering it from waves.
breast line
A line attached laterally from a boat to a dock, preventing movement away from the dock.
breast rope
The mooring rope or anchor warp that is used on yachts and cruisers
bridge
The room from which a ship is controlled. On a smaller boat this is usually not a room, is outside, and is known as a cockpit.
bridge deck
Mostly used to describe the intermediate deck between cabin and cockpit in small to medium-sized cruisers
bridle
A short length of wire with a line attached at the midpoint. A bridle is used to distribute the load of the attached line. Often used as boom travelers and for spinnaker down hauls.
brig
A two-masted square rigged vessel. On the aft mast, there is also a gaff sail.
brigands
pirates.
brigantine
A two-masted vessel with foremast square rigged, and mainmast fore and aft rigged.
bright work
varnished woodwork or polished metal
bring about
To reverse or change directions, to turn around.
bring to
To stop the forward motion of a boat by heading directly into the wind.
Bristol fashion
A term used to describe a clean and orderly ship. "Shipshape and Bristol fashion."
broach or broach to
a turning or swinging of the boat that puts the beam of the boat against the waves, creating a danger of swamping or capsizing
broaching
The unplanned turning of a vessel to expose its side to the oncoming waves. In heavy seas this could cause the boat to be knocked down.
broad on the beam
The position of an object that lies off to one side of the vessel.
broad reach
A point of sail where the boat is sailing away from the wind, but not directly downwind with the sails let out nearly all the way.
bucko
A bullying and tyrannical officer.
bulb
The lead-torpedo shape on the bottom of the keel.
bulkhead
An interior wall in a vessel. Sometimes bulkheads are also watertight, adding to the vessel's safety.
bullseye
A round eye through which a line is led, usually in order to change the direction of pull.
bulwark
A railing around the deck of a boat to keep things from going overboard and the seas from coming aboard - the part of a ship's side that extends above the main deck to protect it against heavy weather.
bunk
Sleeping Berth
buntline hitch
A type of knot used to attach a line to a shackle.
buoy
A floating device used as a navigational aid by marking channels, hazards and prohibited areas.
buoyancy
Force which enables anything to float. Many boats have built in buoyancy tanks in case of the hull being holed or the boats capsizing.
buoyancy aid
Safety garment to keeps its wearer afloat but (in Britain) one without the qualities that permit it to be called a lifejacket.
buoyancy tanks
Sealed tanks in the hull of dinghies that contain buoyancy to support the boat in case it capsizes
burdened vessel
The vessel responsible for moving out of another vessels path according to the navigation rules. Also known as the give way vessel.
burgee
A type of flag used to identify a boater's affiliation with a yacht club or boating organization. Also used to indicate wind direction.
by the lee
Sailing downwind with the wind blowing over the leeward side of the boat.
by the wind
Sailing close-hauled. Same as "on the wind"
Cab.
Abbreviation for Total Cabins
cabin
A room inside a boat.
cabin sole
The floor of a cabin
cable
A rope or chain made fast to the anchor.
cam cleat
A mechanical cleat used to hold a line automatically. It uses two spring loaded cams that come together to clamp their teeth on the line, which is place between them. Also see jam cleat.
camber
The curvature of an object such as a sail, keel or deck. Usually used when referring to an objects aerodynamic or hydrodynamic properties.
can buoy
A cylindrical buoy painted green and having an odd number used in the United States as a navigational aid. At night they may have a green light. Green buoys should be kept on the left side when returning from a larger body of water to a smaller one. Nun buoys mark the other side of the channel. Also see green and red daymarks
canal
A manmade waterway used to connect bodies of water that do not connect naturally. Canals use locks to raise and lower boats when connecting bodies of water that have different water levels. The Panama and Suez canals are two of the most famous.
canoe stern
A pointed stern, such as those on a canoe.
canvas
Tightely woven cloth used for sails, covers, dodgers and biminis. Typically made from cotton, hemp or linen. Modern sails are made out of synthetic materials generally known as sailcloth. A slang word for a "sail".
cap
A piece of trim, usually wood, used to cover and often decorate a portion of the boat, i.e., caprail.
capsize
When a boat is turned over.
capstan
A rotating drum used to haul heavy lines and chains. Similar to a winch, but mounted vertically.
captain
The person who is in charge of a vessel and legally responsible for it and its occupants.
car
A sliding fitting that attaches to a track allowing for the adjustment of blocks or other devices attached to the car.
caravel
Small trading vessel also used for exploration. Three-masted, usually square rigged on the two forward masts, and having a lateen rigged mizzen mast.
carbon fiber
A synthetic material consisting of fibers glued together with epoxy that is very strong for its weight.
cardinal points
The points of North, South, East and West as marked on a compass rose.
carlins
Structural pieces running fore and aft between the beams.
carrack
Three-masted trading vessel similar to the Caravel, but larger.
carrick bend
A knot used to tie two lines together.
cast off
To detach mooring lines as when leaving a dock.
catamaran
A twin-hulled boat, with hulls side by side.
catboat
A sailboat rigged with one mast and one sail.
catenary
The sag in a line strung between two points.
catspaw
A puff of wind on the water caused by a mass of cool air plunging down through warm surface air.
caulking
Material used to seal the seams in a wooden vessel, making it watertight.
cavitate, cavitation
A type of drag on a propeller caused by air bubbles forming near the tips of a propeller that is spinning too fast. This causes inefficiencies and unnecessary wear and tear on the propeller.
celestial navigation
to calculate your position using time, the position of celestial bodies, and mathematical tables
celestial sphere
An imaginary sphere surrounding the globe that contains the sun, moon, stars and planets.
center of forces
The spot on a vessel on which all forces act centrally
centerboard
A pivoting board that prevents the boat from sliding sideways.
centerboard trunk
A compartment where the centerboard resides.
centerline
The center of the boat: from the stern to the bow.
centre of buoyancy
The centre point of a boats floating ability.
centre of effort
The centre point of a sails energy producing area.
centre of lateral resistance
The epicentre of a boats ability to resist leeway.
certificate
A legal paper or license of a boat or its captain.
chafe
Wear caused by the friction of parts moving past each other.
chafing gear
Tubing or cloth wrapping used to protect a line from chafing on a rough surface.
chain
Metal links that are locked together to make a strong and flexible line. Chains are typically used for anchors and other places where high loads may be exerted on the line, particularly in large vessels.
chain locker
Storage for the anchor chain.
chain plate
The fitting used to attach stays to the hull.
chandlery
A store that sells nautical gear.
channel
A navigable route on a waterway, usually marked by buoys. Channels are similar to roads where the water is known to be deep enough for ships or boats to sail without running aground.
channel marker
A buoy or other mark used to mark a navigable path through a waterway.
Charley Noble
Galley stove pipe
Chart
A nautically specialized map.
chart datum
The water level used to record data on a chart. Usually the average low tide water level.
chart table
A table designated as the area in the boat where the navigator will study charts and plot courses.
cheek block
A block with one end permanently attached to a surface.
chief mate
The officer second in command of a ship.
chine
The location where the deck joins the hull of the boat. The angle between the side and the bottom of a boat.
chockablock
When a line is pulled as tight as is can go, as when two blocks are pulled together.
chocks
a heavy metal fitting fixed to the deck of a ship through which a line for mooring, towing, or anchor rode is passed
chop
Small, steep disorderly waves.
chronometer
An accurate clock that is used for navigation.
chute
A spinnaker.
ciguatera
a severe type of food poisoning caused by eating contaminated fish
class
A group of boats of the same design, relevant for races and regattas
clear the decks
remove unnecessary things from the decks
cleat
A fitting for securing a line. It can be wooden, metal or nylon.
cleat hitch
A figure eight pattern used to tie a line to a cleat.
clevis pin
A metal pin used to attach fittings to each other or their mounts.
clew
The lower aft corner of a sail.
close hauled
Sailing with the sails hauled tight, sailing the boat towards the wind as much as possible.
close reach
Steering off a close-hauled course by approximately 20 degrees
close up
A flag hoisted to the top of a flagpole. Also see "at the dip".
close winded
A boat that is able to sail well into the wind.
clove hitch
A knot for temporarily fastening a line to a spar or piling.
club
A boom on a jib or staysail.
club footed
A jib or staysail that utilizes a small boom.
club
Societies of mostly non-professional sailors that sail for pleasure; the first sailing clubs developed in the 17th century in England
CNG
Compressed natural gas. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
coach roof
Also trunk. The cabin roof, raised above the deck to provide headroom in the cabin.
coaming
A small wall to prevent water from entering the cockpit.
coast
The region of land near the water.
coast pilots
Books covering information about coastal navigation, including navigational aids, courses, distances, anchorages and harbors.
coastal navigation
Navigating near the coast, allowing one to find one's position by use of landmarks and other references.
cock
A valve used to regulate the flow of water or gas.
cockpit
The location from which the boat is steered, usually in the middle or the rear of the boat.
cockpit sole
Sole (floor) of the cockpit.
code
Any method of passing messages, such as visual or electronic morse code, code flag pennants and semaphore.
coil
To lay a line down in circular turns.
cold front
Used in meteorology to describe a mass of cold air moving toward a mass of warm air. Strong winds and rain typically accompany a cold front.
cold molding
A method of bending a material into an appropriate shape without heating or steaming to soften the material first.
collision bulkhead
A watertight forward bulkhead designed to keep the boat from sinking in the event of a collision.
colours
The national flag and or other flags.
COLREGS
A term for the international rules designed to prevent collisions between boats.
come about
To bring the sail from one side of the boat to the other, when sailing into the wind, A maneuver in tacking.
communication system
Radio or satellite systems used on yachts for communication
companionway
The entryway into the cabin from the deck.
compass
An instrument that uses the earth's magnetic field to point to the direction of the magnetic north pole. A device used to draw circles.
compass card
A card labeling the 360° of the circle and the named directions such as north, south, east and west.
compass course
The course as read on a compass. The compass course has added the magnetic deviation and the magnetic variation to the true course.
compass error
Magnetic deviation. The difference between the reading of a compass and the actual magnetic course or bearing due to errors in the compass reading. These errors can be caused by metals, magnetic fields and electrical fields near the compass. Prior to using a compass, magnetic deviation should be recorded for many different points on the compass as the error can be different at different points. The act of checking for magnetic deviation is called swinging.
compass north
The direction in which the compass points ? not matching the geographic north
compass rose
A circle on a chart indicating the direction of geographic north and sometimes also magnetic north. Charts usually have more that one compass rose. In that case the compass rose nearest to the object being plotted should be used as the geographic directions and magnetic variations may change slightly in different places on the chart.
composite construction
An object made with more than one type of material.
compressed natural gas
CNG for short. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
continent
A large land mass, such as Africa, Antarctica, Asia, Australia, Europe, North America, and South America.
continental shelf
A region of relatively shallow water surrounding each of the continents.
coordinated universal time
A time standard that is not affected by time zones or seasons. Time measured in coordinated universal time labeled with the term zulu. It is used so that people around the world can communicate about time without regard to individual time zones.
cordage
Any rope or line.
cotter pin
A small metal pin used to keep other parts from changing their position, such as to keep a nut from turning or a clevis pin from falling out.
counter
The part of the hull that lies above the water at the stern.
course
The direction the boat is traveling or intends to travel. A path which racing boats are to follow.
courtesy flag
A smaller version of the flag of the country being visited. It is flown from the starboard spreader.
cove
A small sheltered recessed area in the shoreline.
cowls
Scoop like devices used to direct air into a boat.
coxswain
Sailor commanding or navigating a small boat
CQR anchor
Also called a plow anchor. Short for coastal quick release anchor. An anchor that is designed to bury itself into the ground by use of its plow shape.
crabbing
going sideways due to set (also catching crabs!)
cradle
A frame to support a vessel when out of water.
crest
The top of a wave or the act of reaching the top of a wave.
crew
One or more people that aid in the operation of a sailboat.
cringle
A fitting in a sail that allows a line to fasten to it.
crossing situation
When two vessels approach each other and their paths are crossing. The boat with the other boat on its starboard side is the give way vessel and must yield.
crosstrees
Horizontal members attached to the mast acting as spreaders for the shrouds
cruise
Pleasure trip on a yacht or ship
cruising guides
Books that describe features of particular sailing areas, such as hazards, anchorages, etc.
cuddy
Shelter on a boat not large enough to be a cabin.
cunningham
A line used to control the tension along a sail's luff in order to maintain proper sail shape.
current
The movement of water, due to tides, river movement and circular currents caused by the motion of the earth.
cutter
A sailboat with a single mast placed in the middle of the boat.
cutwater
The front edge of the boat.
D signal
safety signal, "Keep clear of me. I am maneuvering with difficulty."
dacron
A synthetic polyester material.
dagger board
A type of centre board that adjusts vertically in the well.
danbuoy
A marker that is attached to a lifebuoy
danforth anchor
A brand of lightweight anchor. It has pivoting flukes that dig into the ground as tension is placed on the anchor. It does not have a stock.
danger zone
The area encompassed from dead ahead of your boat to just abaft your starboard beam. You must stand clear of any boat in the "danger zone".
davit
A device that projects beyond the side of the boat to raise objects from the water. Typically a single davit is used on the bow of a vessel to raise an anchor, and a pair are used on the side or stern of the vessel to raise a dinghy.
daybeacon, daymark
A navigational aid visible during the day. In the United States and Canada, square red daybeacons should be kept on the right and triangular green daybeacons should be kept on the left when returning from a larger to smaller body of water. Also see can and nun buoys.
daysailer
A small boat intended to be used only for short sails or racing.
dayshape
Black diamond, ball, and cone shapes hoisted on vessels during the day to indicate restricted movement ability or type. For example three balls means aground.
dead ahead
A position directly in front of the vessel.
dead astern
A position directly behind the vessel.
dead before
Running with the wind directly behind the boat.
dead downwind
Sailing straight with the wind.
dead reckoning
A method of determining position by making an educated guess based on last known position, speed and currents.
dead-eyes
Blocks in the shroud rigging used to adjust tension
deadhead
a floating log
deadlight
Fixed ports that do not open, placed in the deck or cabin to admit light.
deadrise
The measurement of the angle between the bottom of a boat and its widest beam. A vessel with a 0º deadrise has a flat bottom, high numbers indicate deep V shaped hulls.
deck
The surface on the top of the boat that people can stand on.
deck plate
a metal plate fitting on the deck that can be opened to take on fuel or water
deck stepped
A mast that is stepped (placed) on the deck of a boat rather than through the boat and keel stepped. The mast of a deck stepped boat is usually easier to raise and lower and are usually intended for lighter conditions than keel stepped boats.
deckhand
A crew member responsible for cleaning the deck, and an overall boat maintenance.
deckhead
The underside of the deck, viewed from below (the ceiling.)
delaminating
A 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 core.
depression
Low-pressure area in meteorology
depth sounder
An instrument that uses sound waves to measure the distance to the bottom.
derelict
Any abandoned vessel.
design waterline (DWL)
Also length waterline or load waterline (LWL) - The length of the boat where it meets the water when loaded to its designed capacity.
deviation
See magnetic deviation or compass error.
dew point
The point of temperature and air pressure at which water vapor forms mist or fog
DGPS
Differential Global Positioning System
dinghy, dink
A small boat used to travel from a boat to shore, carrying people or supplies. Also known as a dink or tender.
dismast
The loss of a mast on a boat. Generally this also means the loss of some or all of the ability of the boat to sail.
displacement
The weight of a boat measured as a the weight of the amount of water it displaces. A boat displaces an amount of water equal to the weight of the boat, so the boat's displacement and weight are identical.
displacement hull
A type of hull that only floats, even when in motion, as opposed to a type of hull that allows a boat to skim across the surface of the water. See planing hull.
displacement speed
Also hull speed. The theoretical speed that a boat can travel without planing, based on the shape of its hull. This speed is 1.34 times the length of a boat at its waterline. Since most monohull sailboats cannot exceed their hull speed, longer boats are faster.
distance made good
The distance traveled after correction for current, leeway and other errors that may not have been included in the original distance measurement.
distress signals
Any signal that is used to indicate that a vessel is in distress. Flares, smoke, audible alarms, electronic beacons and others are all types of distress signals.
ditty bag
A small bag.
dive flag
A red flag with a white stripe. Flag displayed by boats if they have divers in the water.
dividers
A navigational tool used to measure distances on a chart.
dock
An platform where vessels can make fast. The act of securing a boat in such a place. Docks are often subdivided into smaller areas for docking known as slips.
documentation
Licenses or registration papers for a vessel. Types of documentation vary depending on the country, vessel size and purposes.
dodger
A cover attached to the top of the cabin at the front of the cockpit. Dodgers help shelter the cockpit from wind and water.
doldrums
An area between the weather systems of the Northern and Southern Hemispheres characterized by frustrating light winds, major shifts in wind direction and sudden violent squalls.
dolphin
A group of piles driven close together and bound with wire cables into a single structure.
dorade vent
A type of vent designed to let air into a cabin and keep water out by the use of baffles.
double ender
boat with a pointed bow and stern
double-braid
A line consisting of a braided inner core and a braided outer sheath.
douse
To drop a sail quickly. To extinguish flames.
down helm
To steer a sailboat toward the wind.
downhaul
A line used to pull down on a spar or sail.
downwind
In the direction the wind is blowing.
draft
The depth of a boat, measured from the deepest point to the waterline. The water must be at least this depth or the boat will run aground. Also describes amount of curvature in a sail.
drag
The resistance to movement.
dragging
Description of an anchor that is not securely fastened to the bottom and moves.
draw
Draft. The depth of water that a boat requires to stay off the bottom. A vessel "draws" a certain amount of water.
drawbridge
A bridge that can be raised vertically to allow boats to pass underneath.
drift
The velocity of a current.
driving force
Force produced by catching wind in a sail and transmitting the energy into a the mast
drogue
Any object used to increase the drag of a boat. Typically shaped like a parachute or cone opened underwater, drogues slow a boat's motion in heavy weather. Also see sea anchor.
dry dock
A dock where a boat can be worked on out of the water. The boat is usually sailed into a dry dock and then the water is pumped out.
dry rot
Used to describe the decay of wood. A misnomer, dry rot is actually caused by moist conditions in fresh water.
dry sailing
When boats, especially smaller racers, are kept on shore instead of being left anchored or moored, they are dry sailed. the practice prevents marine growthon the hull and the absorption of moisture into it.
dry storage
Storing on land. Many small boats are placed in dry storage over the winter.
ducts
Tubes used to move air, such as to ventilate an enclosed area.
E
In sail measurements, the longest reach of the mainsail along the boom.
ease
To slowly loosen a line while maintaining control, such as when loosening the sails.
ease the sheets
To loosen the lines that control the sails.
east
One of the 4 cardinal compass points. East is at 90° on a compass card.
east wind, easterly wind
A wind coming from the east.
ebb
A receding current.
ebb tide
A receding tide.
echo sounder
An electrical fish finder or depth sounder that uses sound echoes to locate the depth of objects in water. It does so by timing the sound pulses.
eddy
Water or air currents flowing in circular patterns.
el Nino
a warm inshore current annually flowing south along the coast of Ecuador. About every seven to ten years it extends down the coast of Peru , where it has a devastating effect.
electronic navigation
The use of echo sounders, radio, and various electronic satellite and land based position finders to determine a boat's location.
emergancy tiller
A tiller that is designed to be used in the event that wheel steering fails.
Emiz
The longest reach of the mizzen along its boom.
ensign
The national flag of a boat's home nation.
entrance
The area of a bow that first meets the water.
EP
Estimated Position, a value plotted on a map or chart in temporal intervals
EPIRB
Emergency Position Indication Radio Beacon. Radio signaling aid that allows the transmission of emergency position calls
equator
An imaginary line around the center of the world at 0° of latitude.
escape hatch
The escape hatch is usally a deck hatch that is set into the side of the catamarn hull to be used for emergency exit
estimated position
A position based on dead reckoning estimations of a boat's position using estimated speed, currents, and the last known position (fix) of the boat.
even keel
When a boat is floats evenly to its waterline, well balanced.
eye of the wind
The direction that the wind is blowing from.
eye splice
A splice causing a loop in the end of a line, by braiding the end into itself or similar methods. It may or may not be reinforced by a metal fitting known as a thimble.
fair
In good condition.
fair wind
Wind when it is favorable to the course being steered.
fairlead
A fitting designed to control the direction of a line with minimal friction.
fall off
Also bear away or bear off. A boat falls off the wind when it points its bow further from the eye of the wind. The opposite of heading up.
fastening
An item such as a nail, screw, rivet or other device used to fasten objects together.
fathom
A nautical measurement equaling 6 feet (182 cm). Usually used to measure depth.
fathometer
A brand name for a depth measuring device.
feathering
A propeller that can have the pitch of its blade changed to reduce drag when not in use. Also see folding and variable pitch propellers.
feet
More than one foot. A foot is a unit of measurement used primarily in the United States. 1 foot equals 30.48 centimeters.
fend off
To push a boat away from another boat or dock by hand.
fender
A cushion hung from the sides of a boat to protect it from rubbing against a dock or another boat.
fetch
The distance that the wind travels over open water that determines the size of a wave - the longer the fetch, the higher the waves.
fiberglass
A construction method using layers of woven glass mats that are bonded together with an epoxy (glue).
fid
A pointed tool used to separate strands of rope.
fiddle
A small rail on tables and counters used to keep objects from sliding off when heeled or in heavy seas.
figure eight knot
A common knot that is often used to prevent lines and ropes from slipping through a fitting.
figurehead
An ornamental carved and painted figure on the stem of the vessel.
fin keel
A keel that is narrow and deeper than a full keel.
finger pier
A small pier that projects from a larger pier.
fisherman anchor
Kedge anchor. A traditionally shaped anchor having flukes perpendicular to the stock of the anchor and connected by a shank. These are less common than modern anchors such as the plow and lightweight anchors.
fishhook
slang sailing expression for a piece of metal or shroud that cuts or stabs you, the injury usually not discovered until later
fix
An accurate position of the vessel, as determined by any reasonably accurate method, such as by taking visual bearings.
flake
To fold a sail in preparation for storage.
flame arrester
A device used to prevent or stop unwanted flames.
flare
A device which burns to produce a bright light, sometimes colored, and usually used to indicate an emergency. Outward curve of boat's sides.
flashing
Used to describe a light that blinks on and off in regular patterns.
flemish
To coil a line flat on the deck in spirals.
flinders bar
An iron bar mounted on or near the compass to correct for magnetic deviation in steal hulled ships.
flood
incoming tidal current
flood tide
The incoming tide where the water comes in from the sea, lowering the water level.
flotsam
Debris floating on the water surface.
fluke
The broad flat parts of an anchor that are designed to grab and hold in the bottom.
flush deck
A deck that is not obstructed by a cabin.
flying bridge
A high position from which to steer a boat.
fo'c'sle
An abbreviation of forecastle. Refers to that portion of the cabin which is farthest forward. In square-riggers often used as quarters for the crew.
foil
An attachment on the forestay, comprising a groove into which the luff of the jib can be fed.
foils
Underwater parts of a boat
folding
A propeller having blades that fold up when not in use to reduce drag. Also see feathering and variable pitch propellers.
following sea
A sea with waves approaching from the stern of the boat.
foot
The bottom edge of a sail. Unit of measurement (30.48 cm)
force 8
Gale force wind on the Beaufort Wind Scale
fore
Toward the bow (front) of the vessel.
fore and aft
Running along the length of the boat.
fore and aft sail
The more common position of the sail with its length running along the ship's length as opposed to a sail such as a square sail which is mounted across the width of the vessel.
forecabin
The cabin towards the front of the vessel.
forecast
A weather prediction.
forecastle
Also fo'c'sle or fo'csle. Pronounced fo'csle. The most forward below decks area of a vessel.
foredeck
The forward part of the deck.
forefoot
The point where the stem joins the forward end of the keel.
foremast
The forward mast of a two or more masted vessel.
forepeak
The compartment farthest forward in the bow of the boat. Often used for anchor or sail stowage. In larger ships the crews quarters
foresail
A sail placed forward of the mast, such as a jib.
forestay
Sometimes called a jibstay, or a headstay. A cable supporting the mast, running from the bow to the top of the mast.
forestaysail
A sail attached to the forestay as opposed to a jib which is attached to the headstay.
foretriangle
The space between the mast, the deck, and the headstay.
forward
Toward the bow (front) of the boat.
forward quarter spring line
A mooring line running forward from the stern of the boat. The forward quarter spring line prevents the boat from moving backward while moored. The after bow spring line does the opposite.
foul, fouled
When a line ends up somewhere it does not belong and becomes jammed. Lines can foul on blocks, winches and other objects on a boat.
foul weather gear
Gear, clothing or accessories that are designed to accommodate needs that arise from bad weather issues
founder
Used to describe a boat that is having difficulty remaining afloat. "The boat foundered and then sank."
fractional rig
A type of rig where the jib attaches below the top of the mast.
frames
The rib-like structures that shape and stiffen the hull of any vessel
freeboard
The distance between the top of the hull and the waterline.
freeing port
An opening in the rail (bulwarks) along the deck to allow water to drain.
freer
A change in the wind direction to the aft of a boat
freestanding mast
A mast made out of exotic materials so that it can support itself without the use of stays. See fully stayed mast.
fronts
Used in meteorology to describe bounderies between hot and cold air masses. This is typically where bad weather is found.
full and by
Sailing as close to the wind as possible with full sails.
full keel
A keel that runs the length of the boat. Full keels have a shallower draft than fin keels.
fully battened
A sail having battens that run the full horizontal length of the sail.
fully stayed
A mast supported by the use of lines known as stays and shrouds.
Furious Fifties
An area between 50 degrees and 60 degrees latitude noted for very strong winds and huge seas.
furl
To roll a sail up and secure it to yard or boom.
futzing
meddling or fooling around
gaff
A spar that holds the top of a four sided gaff sail. A hooked pole for getting fish on board.
gaff rigged
A type of traditional working boat using four sided gaff sails that are hoisted on gaffs.
gaff sail
A four sided sail used instead of a triangular main sail. Used on gaff rigged boats.
gaff topsail
A triangular sail set over a gaff.
gale
A storm with a wind speed between 34 to 40 knots.
gale force winds
Wind speeds strong enough to qualify the storm as a gale.
galley
The kitchen area on a boat.
gallows frame
A frame used to support the boom.
gangway
The area of a ship's side where people board and disembark.
garboard
The lowest part of a hull next to the keel. The planks each side of the keel are the 'garboard strakes'.
gasket
Ties used to tie up the sails when they are furled.
gear
All equipment used for sailing except the boat itself; rather a commercial than a nautical term; read our gear checklist
gel coat
The gel coat is the terminology used for the pigmented outside coat of a GRP boat (fiberglass)
gennaker
A large sail that is a cross between a spinnaker and a genoa. Hoisted without a pole, the tack is attached at the bottom of the headstay.
genoa
A large jib that overlaps the mast. Also known as a jenny.
geographic north
The direction toward the top point of the line about which the earth rotates (between Canada and Russia in the Arctic Ocean.) See also magnetic north.
geographic position
The position of a boat on a chart.
gimbals
Hinges for objects such as lamps, compasses and stoves so that they can remain upright as the boat rolls.
give-way
To yield the right of way to another boat.
give way together
Command used by Coxswain in larger rowing boats
give way vessel
The vessel that must yield to another vessel according to the navigation rules. Also known as the burdened vessel.
global positioning system
GPS for short. A system of satellites that allows one's position to be calculated with great accuracy by the use of an electronic receiver.
globe
A map of the earth drawn on a sphere so that both its distances and angles are accurate.
gloves
Sailing gloves protect hands of competitive sailors and allow the fast handling of wires and lines
GMDSS
Global Maritime Distress and Safety System
GMT
Time measured in Greenwich Mean Time. Coordinated universal time is a newer standard. A time standard that is not affected by time zones or seasons.
go about
Change tack to bring wind to the other side.
going to weather
to sail against the prevailing wind and seas
gollywobbler
A full, quadrilateral sail used in light air on schooners. It is flown high, between the fore and main mast, and is also known as a fisherman's staysail.
gooseneck
Universal joint fitting that links the end of the boom to the mast.
goosewinging
Sailing downwind with a mainsail set on one side and the foresail on the other
grab rails
Hand-hold fittings mounted on cabin tops and sides for personal safety when moving around the boat.
granny knot
A bad knot that was probably tied in error, will not necessarily hold fast, and may be difficult to untie.
great circle
Any circle drawn around the earth such that the center of the circle is at the center of the earth. The shortest distance between any two points on the earth lies along a great circle.
great circle route
A course that is the shortest distance between two points, following a great circle. Great circle routes usually do not look like the shortest route when drawn on a flat map due to deviations caused by trying to draw a flat map of a round object such as the earth.
green buoy
A can buoy. A cylindrical buoy painted green and having an odd number used in the United States as a navigational aid. At night they may have a green light. Green buoys should be kept on the left side when returning from a larger body of water to a smaller one. Nun buoys mark the other side of the channel. Also see green and red daymarks.
green daymark
A navigational aid used in the United States and Canada to mark a channel. Green triangular daymarks should be kept on the left when returning from a larger to smaller body of water. Red daymarks mark the other side of the channel. Also see can and nun buoys.
green water
A solid mass of water coming aboard instead of just spray.
grommet
A ring or eyelet normally used to attach a line, such as on a sail.
ground swells
Swells that become shorter and steeper as they approach the shore due to shallow water.
ground tackle
The anchor and its rode or chain and any other gear used to make the boat fast.
GRP
Glass-reinforced plastic, the most common material in boat manufacturing these days
gudgeon
The hole in which the pin from a stern mounted rudder fits. The pin is known as a pintle.
gunkholing
Cruising in shallow water and spending the nights in coves.
gunnel, gunwale
Pronounced gunnel. The rail around the edge of a boat. Smaller versions are called toe rails.
gunter rig
Similar to a gaff rig, except that the spar forming the "gaff" is hoisted to an almost vertical position, extending well above the mast.
guy
Also called a brace. A line used to control the movement of the object at the other end, such as a spar.
gybe
To change tack, sailing downwind (also Jibe)
gypsy
A windlass or capstan drum.
gyres
A large circular ocean current.
hail
To attempt to contact another boat or shore, either by voice or radio.
half hitch
A simple knot usually used with another knot or half hitch.
halyard/halliard
A line used to raise things on a boat, for example "the main halyard" is the line used to raise the mainsail. It is a part of running rigging.
hand
Someone who helps with the work on a boat.
hand bearing compass
A small portable compass.
hand lead
A weight attached to a line used to determine depth by lowering it into the water.
hand rail
A hand hold. Usually along the cabin top or ladder.
handsomely
To do something carefully and in the proper manner, such as when stowing a line.
handy-billy
A movable block and tackle.
hanging locker
A locker big enough to hang clothes.
hank
A snap - plastic or stainless steel - attached to the luff of the jib, used to attach the jib to the forestay.
harbour
An anchorage protected from storms either naturally or by man-made barriers.
harbourmaster
The individual who is in charge of a harbor.
hard aground
A boat which has gone aground and cannot break free under her own power.
hard chine
An abrupt intersection between the hull side and the hull bottom of a boat so constructed.
hard-chined
A hull shape with flat panels that join at sharp angles.
hard over
To move all the way in one direction, such as when turning the wheel.
hard-a-lee
A command to steer the boat downwind.
harden up
to steer closer to the wind, usually by pulling in on the sheets
hatch
A small opening with a "door" on deck, allowing entry under the deck.
haul
Pulling on a line.
haul around
change from a run to a reach
haul it in
Adjust sails and rudder so boat is stopped safely.
haul out
Remove a boat from the water.
hauling part
The part on the object which is hauled upon.
hawse hole
A hole in the hull for mooring lines to run through.
hawsepipes
Pipes to guide lines through the hawse hole. On large vessels anchors are stored with their shanks in the hawsepipes.
hawser
A rope that is very large in diameter, usually used when docking large vessels.
hazard
An object that might not allow safe operation. A group of rocks just under the water or a submerged wreck could be a navigational hazard.
head
The front of a vessel. The upper corner or edge of a sail. The toilet and toilet room on a ship.
head knocker
A block with a jam cleat, located on the boom and used to control the main sheet on small boats.
head sea
A sea which is traveling in the opposite direction to that of the boat.
head to wind
A position with the boat's bow in the direction that the wind is coming from. This will probably stop the boat and place it in irons.
head up
To turn the bow more directly into the eye of the wind. The opposite of falling off.
headaway, headway
Forward motion of a boat
headboard
Wood or metal plate fixed in the head of a sail.
header
Change in the wind direction to forward of the boat
headfoil
a grooved rod fitted over the forestay to provide support for luff of the sail or help support the forestay
heading
The actual course of the vessel at any given time.
headsail
Any sail forward of the mast, such as a jib.
headstay
The stay leading from the mast to the bow.
heave
To throw or pull strongly on a line.
heave to
to stop forward movement by bringing the vessel's bow into the wind and keeping it there
heaving to
Arranging the sails in such a manner as to slow or stop the forward motion of the boat, such as when in heavy seas.
heaves
upward displacing swells
heaving line
A light line used to be thrown ashore from which a larger rope can then be pulled.
heavy seas
When the water has large or breaking waves in stormy conditions.
heavy weather
Stormy conditions, including rough, high seas and strong winds. Probably uncomfortable or dangerous.
heel
the lean of a sailboat when sailing; the extent of the tilt of the boat
heel brace
The iron support at the bottom of a rudder
heeling error
The error in a compass reading caused by the heel of a boat.
heeling force
Force that results from the sum of the sideways force and resistance from the keel
helm
The wheel or tiller of a boat.
helm's alee
A warning from the helmsman that the boat is about to tack.
helmsman
The person who is steering the boat.
hemisphere
Half of a sphere. On the globe hemispheres are used to describe the halves of the earth north or south of the equator.
high
A location of higher barometric pressure than the surrounding area of a weather system.
high tide
The point of a tide when the water is the highest. The opposite of low tide.
hike out
climb to windward
hike
Leaning out over the side of the boat to counteract heel.
hiking
Moving the crew's weight to or past the windward rail to counteract the heeling of a boat. Typically seen when boats are racing.
hiking stick
An extension to the tiller allowing the helmsman to steer while hiking. This may be desired for improved visibility or stability.
hitch
A knot used to attach a line to a cleat or other object.
hoist
To raise a sail or anything else up.
hold
A compartment below deck in a vessel, used solely for carrying cargo.
holding ground
The type of bottom that the anchor is set in. "Good holding ground."
holding tank
A storage tank where sewage is stored until it can be removed to a treatment facility.
homing
Using a radio direction finder to steer toward a source of radio signals.
hook
anchor
horizon
Where the water and sky or ground and sky appear to intersect.
horizontal angle
The angle measured between two fixed objects (usually on shore) to aid in finding a boats position by determining the arc of a circle on which the boat must lie.
horseshoe buoy
A floatation device shaped like a U and thrown to people in the water in emergencies.
hounds
The attachment points for the shrouds up the mast.
hove to
see heave to
hull
The body of a boat
hull speed
the fastest a sailboat will go, usually dependent on length of the hull at the waterline
hurricane
A strong tropical revolving storm of force 12 or higher in the northern hemisphere. Hurricanes revolve in a clockwise direction. In the southern hemisphere these storms revolve counterclockwise and are known as typhoons.
hydrodynamic
A shape designed to move efficiently through the water.
hydrofoil
A boat that has foils under its hull onto which it rises to plane across the water surface at high speed. See displacement and planing hulls.
hydrography
The study of the earth's waters.
I
In sail measurements, the height of the foretriangle. It is measured from the deck to the highest useful point on the forward side of the mast. Can be either the point where the forestay is attached to the mast, or if mounted above the forestay, the top of the spinnaker block.
IALA
International Association of Lighthouse Authorities
ice sailing
Navigating vessels on blades over ice using sails
impeller pump
A type of pump commonly used on large sailing vessels
in ballast
Carrying ballast, but no cargo
in irons
All way lost when attempting to tack. The boat is pointing into the wind with the sails flapping, but it will not pay off on to either tack by its own momentum and is temporarily out of control.
inboard
Toward the center of the boat. An engine mounted inside the boat.
inboard cruiser
A motorboat with an inboard engine.
inches of mercury
A unit used when measuring the pressure of the atmosphere. 33.86 millibars. Inches of mercury are used because some barometers use the height of mercury in a sealed tube as a measuring device.
inflatable
A dinghy or raft that can be inflated for use or deflated for easy stowage.
inland
Away from large bodies of water, surrounded by land. See offshore.
Inland Rules
Rules for the operation of vessels in harbors, rivers and lakes.
inlet
A bay or cove along a river, sea or lake coast line. A stream or bay leading inland. A narrow passage between to bodies of land.
inspection port
A watertight covering, usually small, that may be removed so the interior of the hull can be inspected or water removed.
intercoastal waterway (ICW)
A system of rivers and canals along the Atlantic and Gulf Coasts of the United States allowing boats to travel along them without having to go offshore.
International Code of Signals
A set of radio, sound, and visual signals designed to aid in communications between vessels without language problems. It can be used with Morse Code, with signal pennants, and by spoken code letters.
inverter
electrical power converter; converts square-wave DC current to sine-wave AC current
iron spinnaker
auxiliary engine
isobars
Bars or lines on meteorological maps to show pressure areas
isogonic lines
A line connecting points of equal magnetic variation on a map.
J
In sail measurements, the base of the foretriangle. It is measured from the forestay at the stem to the forward side of the mast, horizontally to the waterline.
jack line, jack stay
A strong line, usually of flat webbing, or a wire stay running fore and aft along the sides of a boat to which a safety harness can be attached.
jack-tar
a sailor from the clipper ship days, so named because they would tar their hair to prevent infection and make it easy to cut
jacob’s ladder
A rope ladder that leads off the deck to allow passengers and crew to disembark or board
jam cleat
A cleat designed to hold a line in place without slipping. It consists of two narrowing jaws with teeth in which the line is placed. Also see cam cleat.
jaws
A fitting holding a boom or gaff to the mast.
jenny
A genoa jib. A large jib that overlaps the mast.
jetsam
debris, jettisoned items, floating at sea
jettison
To throw overboard.
jetty
A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.
jib
A triangular sail attached to the headstay. The front sail. A jib that extends aft of the mast is known as a genoa.
jib halyard
The line that raises and lowers the jib.
jib netting
A rope net to catch the jib when it is lowered.
jib sheets
A sheet (line) used to control the position of the jib. The jib has two sheets, and at any time one is the working sheet and the other is the lazy sheet.
jib stay
The stay that the jib is hoisted on. Usually the headstay.
jib topsail
A small jib set high on the headstay of a double headsail rig.
jibe
also gybe; to turn the boat downwind from one side of the wind to the other
jiffy reefing
A method of lowering the sail in sections so that it can be reefed quickly.
jig
fishing technique of lowering a weighted lure until just above the bottom, then alternately jerking the rod upwards and lowering it to give action to the lure
jigger
A small sail on the mizzen mast of a yawl or a ketch.
jumbo
The larger of the headsails.
jumper stay
A short stay supporting the top forward portion of the mast. The stay runs from the top of the mast forward over a short jumper strut, then down to the mast, usually at the level of the spreaders.
junction buoy
Also known as a preferred channel buoy. A red and green horizontally striped buoy used in the United States to mark the separation of a channel into two channels. The preferred channel is indicated by the color of the uppermost stripe. Red on top indicates that the preferred channel is to the right as you return, green indicates the left. Also see can and nun buoys.
junk
A sailing vessel common in the Far East, has two or three masts carrying battened lugsails.
jury rig
A temporary or emergency repair using improvised materials and parts.
kedge anchor
A secondary, lighter anchor. Traditionally shaped anchor having flukes perpendicular to the stock of the anchor and connected by a shank. These are less common than modern anchors such as the plow and lightweight anchors.
kedging
To kedge off. A method of pulling a boat out of shallow water when it has run aground. A dinghy is used to set an anchor, then the boat is pulled toward the anchor. Those steps are repeated until the boat is in deep enough water to float.
keel
A weighted extension of a boat running below it that prevents the boat from sliding sideways.
keel stepped
A mast that is stepped (placed) on the keel at the bottom of the boat rather than on the deck. Keel stepped masts are considered sturdier than deck stepped masts.
keelson
A beam attached to the top of the floors to add strength to the keel on a wooden boat.
ketch
A sailboat with two masts. The shorter mizzen mast is aft of the main mast, but forward of the rudder post. A similar vessel, the yawl, has the mizzen mast aft of the rudder post.
kick-up
A rudder or centerboard that is able to kick-up when it hits a solid obstacle
king plank
The center plank on a wooden deck.
king spoke
The top spoke on a wheel when the rudder is centered.
kite
Sometimes used to indicate spinnaker.
knees
Supporting braces used for strength when two parts are joined.
knockabout
A type of schooner without a bowsprit.
knocked down
A boat that has rolled so that she is lying on her side or even rolled completely over. A boat with appropriate ballast should right herself after being knocked down.
knot
A speed of one nautical mile per hour. A method of attaching a rope or line to itself, another line or a fitting.
labour
Heavy rolling or pitching while underway.
lacing
A line used to attach a sail to a spar.
laid up
A boat in a dry dock.
land breeze
A wind moving from the land to the water due to temperature changes in the evening.
landfall
first sight of land
landlocked
Surrounded by land.
landmark
A distinctive reference point that can be used for navigation.
lanyard
a short rope or cord that attaches to an item onboard a boat , usually for keeping it attached to the boat
lapper
A foresail that extends backwards beyond the mast and thereby, overlapping it
lash
To tie something using a light rope.
lateen
A triangular sail mounted on a spar along the sails luff.
lateral resistance
The ability of a boat to keep from being moved sideways by the wind. Keels, daggerboards, centerboards, and leeboards are all used to improve a boat's lateral resistance.
latitude
an angular measurement or distance measured in degrees, north or south from the equator which is 0 .
launch
To put a boat in the water. A small boat used to ferry people to and from a larger vessel.
lay
The position of an item. The direction in which a stranded rope is twisted.
lay line
An imaginary line on which a sailboat can sail directly to its target without tacking.
lay up
To prepare a boat for winter storage.
lazaret, lazarette
a storage space below the deck in the cockpit
Lazy Jack
Light lines from the topping lift to the boom, forming a cradle into which the mainsail may be lowered.
lead
Refers to the direction in which a line goes. A boom vang, for example, may "lead to the cockpit."
league
Three nautical miles.
lee
The side sheltered from the wind.
lee boards
Pivoting boards on either side of a boat which serve the same function as a centerboard. The board to leeward is dropped, the board to windward is kept up.
lee cloths
a cloth hung on the lee side of a berth (the down side when the boat has heel to it) to keep one from rolling out of their bunk
lee helm
The leeward course an unsteered boat takes
lee shore
Shore on which the wind is blowing from seawards.
leech
The aft edge of a fore-and-aft sail.
leech line
A line running through the leech of the sail, used to tighten it.
leeward
The direction away from the wind. Opposite of Windward.
leeway
The sideways movement of the boat caused by either wind or current.
length over all (LOA)
Length of a boat at the longest measurement.
lie to
To head into the wind and stop forward motion.
life raft
An inflatable craft into which the crew of a yacht transfers if the yacht intends to sink.
lifejacket
Buoyant garment. In Britain the name is reserved for one that will turn a person the rightway up. Otherwise its called a buoyancy aid.
lifeline
stout line around the deck of the boat to keep crew from falling overboard
lift
The energy generated by sail, hull or foils that moves a boat windward.
line
Any rope used on a boat.
list
inclination of a boat due to excess weight on one side or the other
load water line (LWL)
A line painted on the side of the vessel to which the vessel sinks when carrying its full load.
log
A record of courses or operation. Also, a device to measure speed.
logbook
A boat's record of activity.
longitude
distance in degrees east or west of Greenwich, England, meridian which is 0 .
loose-footed
Describes a mainsail attached to the boom at the tack and clew, but not along the length of it's foot.
lubber line
A mark or permanent line on a compass indicating the direction forward parallel to the keel when properly installed
luff
The fore edge of a sail.
luff rope
Rope sewn into the luff of a sail.
luff up
To luff up means to bring the boat's bow so close to the wind, that the leech of the sail begins to flap.
luffing
To head into the wind, causing sails to flap and flutter.
lug or lugsail
A four sided sail bent onto a yard.
magnetic bearing
The bearing of an object after magnetic variation has been considered, but without compensation for magnetic deviation.
magnetic course
The course of a vessel after magnetic variation has been considered, but without compensation for magnetic deviation.
magnetic deviation
Compass error. The difference between the reading of a compass and the actual magnetic course or bearing due to errors in the compass reading. These errors can be caused by metals, magnetic fields and electrical fields near the compass. Prior to using a compass, magnetic deviation should be recorded for many different points on the compass as the error can be different at different points. The act of checking for magnetic deviation is called swinging.
magnetic north
The direction to which a compass points. Magnetic north differs from true north because the magnetic fields of the planet are not exactly in line with the north and south poles. Observed differences between magnetic and true north is known as magnetic variation.
magnetic variation
The difference between magnetic north and true north, measured as an angle. Magnetic variation is different in different locations, so the nearest compass rose to each location on a chart must be used.
main mast
The tallest (or only) mast on a boat.
main sail
(mainsl') The largest sail on a multiple sail boat.
main sheet
Line that controls the position of the mainsail.
main stay
The line supporting the mast
main topsail
A topsail on the main mast.
make fast
To attach a line to something so that it will not move.
make way
Moving through the water.
marconi rig
Lightweight mast supported by stays and shrouds.
marina
A place where boats can find fuel, water and other services. Marinas also contain slips where boats can stay for a period of time.
mark
Marks used on a lead line or anchor rode indicating the length of the line at that point. A buoy or other object used to mark a location.
marl
To wrap a small line around another.
marline
A small line used for whipping, seizing, and lashing.
marlinespike
A pointed tool used to separate the strands of a rope or wire.
mast
The pole attached to the deck at the right angle, holding up the sails.
mast boot
A protective cover wrapped around the mast at the deck on a keel stepped boat to prevent water from entering the boat.
mast box
A box where a deck stepped mast is stepped.
mast gate
The point at which the mast enters the foredeck of a boat
mast head
The top of the mast.
mast partners
Supporting structures to take the load of the mast at the deck.
mast spanner
A device that allows the control of a rotating mast on catamarans
mast step
Fitting or construction into which the base of the mast is placed.
mast track
A track or groove in the back of the mast to which the sail is attached by means of lugs or the bolt rope.
master
The person in charge of a vessel. The captain.
masthead
The top of the mast.
masthead light
Also known as a steaming light. The masthead light is a white light that is visible for an arc extending across the forward 225° of the boat. When lit the masthead light indicates that a vessel under power, including sailboats with engines running. Masthead lights are usually located halfway up the mast rather than at the top.
masthead rig
A design in which the forestay runs to the peak of the mast.
mastman
The crewmember who works the lines on the mast when hoisting sails, and who assists the bowman with the work on the foredeck.
match racing
A racing format where only two yachts compete at a time
mate
An assistant to the captain.
maxi
A boat designed to the maximum rating allowed under the International Offshore Rule, or more recently, the international measurement system.
mayday
From the French m'aidez, a distress signal.
mean high water
The depth of the water at average high tide.
mean low water
A figure representing the average low tide of a region.
mean lower low water
In an area with two tides, this figure represents the average of the lowest of the low tides.
measured mile
A course marked by buoys or ranges measuring one nautical mile. Measured miles are used to calibrate logs.
meat hook
slang expression for a large fishing hook
mechanical advantage (or purchase)
A mechanical method of increasing an applied force. Disregarding the effects of friction, if a force of 100 pounds applied to a tackle is magnified to a force of 400 pounds, the purchase or mechanical advantage is said to befour to one, or 4: 1.
mediterranean berth
A method of docking with a boat's stern to the dock.
mercator
A type of projection of the globe used when making charts. Since the world is a sphere, it is impossible to draw accurate charts on flat paper. A Mercator projection shows all of the meridians as straight vertical lines rather than lines that would intersect. This is the type of projection used on a typical world map, but the distances become very distorted near the poles.
meridian
A longitude line. Meridians are imaginary circles that run through both poles.
messenger
A small line used to pull a heavier line or cable. The messenger line is usually easier to throw, lead through holes or otherwise manipulate than the line that it will be used to pull.
meteorology
The study of weather.
midchannel buoy
A red and white vertically striped buoy used in the United States to mark the middle of a channel. Midchannel buoys may be passed by on either side. Also see nun and can buoys.
midship
Center of the vessel, middle between bow and stern
midships
A place on a boat where its beam is the widest.
millibar
A unit of pressure used to measure the pressure of the atmosphere. 1 millibar equals 0.03 inches of mercury.
minute
When used to measure location a minute is one sixtieth of one degree. One minute of latitude is equal to one nautical mile. Each minute is divided into sixty seconds.
mizzen mast
A smaller aft mast on a ketch or yawl rigged boat.
mizzen sail
The sail on the aft mast of a ketch or yawl rigged sailboat.
mizzen staysail
A small sail that is sometimes placed forward of the mizzen mast.
monkey deck
A false deck built over a permanent deck. Often used in the bow of larger sailing ships, forward of the anchor windlass and provides a working platform around the portion of the bowsprit as it attaches to the ship.
monkey fist
A large heavy knot usually made in the end of a heaving line to aid in accurate throwing.
monohull
A boat that has only one hull, as opposed to multihull boats such as catamarans or trimarans.
moor, mooring
To attach a boat to a mooring, dock, post, anchor, etc. A secure place where a boat can be moored.
mooring buoy
A buoy marking the location of a mooring. Usually attached to an anchor by a small pendant.
mooring line
A line used to secure a boat to an anchor, dock, or mooring.
morse code
A code that uses dots and dashes to communicate by radio or signal lights.
motor
An engine. The act of using an engine to move a boat.
motor sailer
A boat designed to use its motor for significant amounts of time and use the sails less often than a normal sailboat.
mount
An attachment point for another object. The act of putting an object on its mount.
mouse
Also mousing. Tying a line so that it will not come undone, such as when attaching a line to a hook.
multihull
Any boat with more than one hull, such as a catamaran or trimaran.
mushroom anchor
A type of anchor with a heavy inverted mushroom shaped head. Mushroom anchors are used to anchor in mud and other soft ground.
naked sailing, naturist sailing
A theme for pleasure sailing done with s partly or completely naked crew around which an entire travel industry has evolved; popular for vacations that range from rather “normal” sailing trips done naked to adult swinger cruises
natural gas
Short for compressed natural gas or CNG. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
nautical
Having to do with boats, ships, or sailing.
nautical almanac
A book containing all current data: navigational, tidal, astronomical and so on. It is published annually.
nautical mile
One minute of latitude; approximately 6076 feet - about 1/8 longer than the statute mile of 5280 feet.
navigable water
Water of sufficient depth to allow a boat to travel through it.
navigation
The act of determining the position of a boat and the course needed to safely move the boat from place to place.
navigation lights
At sundown all boats in open water are required to carry lights. The system of lighting differs for each kind of boat.
navigation regulations (or COLREGS)
The regulations governing the movement of vessels in relation to each other, generally called steering and sailing rules.
navigational aid
Any fixed object that a navigator may use to find his position, such as permanent land or sea markers, buoys, radiobeacons, and lighthouses.
navigator
The person responsible for navigating a boat.
neap tide
when the tide range is the least - rising less and dropping less than the other tides during the four week cycle
noon sight
A sighting taken for celestial navigation at noon, when the sun is at its highest point in the sky.
north
One of the 4 cardinal compass points. North is the direction toward the North Pole and is at 0° on a compass card.
north pole
The "top" point of the line about which the earth rotates.
north star
Polaris, the North Star, is visible in the northern hemisphere and indicates the direction of north. In the southern hemisphere the Southern Cross is used to find the direction of south.
north wind, northerly wind
Wind coming from the north.
no-sail-zone
The area of plus minus 45 degrees into the wind in which boats generally can’t sail
notices to mariners
Official notices reporting changes to charts and other navigational and safety items.
nun buoy
A conical buoy with a pointed top, painted red, and having an even number, used in the United States for navigational aids. At night they may have a red light. These buoys should be kept on the right side of the boat when returning from a larger body of water to a smaller one such as a marina. Can buoys are used on the opposite side of the channel. Also see green and red daymarks.
oar
A stick with a blade at the end used to row a rowboat. Oars are different than paddles because they have a provision to be secured to the rowboat for rowing, such as an oarlock.
oarlock
A device to attach oars to a rowboat, allowing the operator to row rather than paddle the boat.
observed position
A position or fix determined by observing landmarks or other objects to find the position.
observation spot
A position of the precise latitude and longitude
occulting lights
A navigational light which turns on and off in a regular pattern, but is on more than it is off. The opposite of a blinking light.
ocean
The large body of salt water covering seven tenths of the earth.
off the wind
Sailing with the wind coming from the stern or quarter of the boat.
offing
seaward, a safe distance from shore
offshore
Away from land, toward the water. See inland.
offshore wind
Wind that is blowing away from the land, towards the water.
old salt
a very experienced and/or old sailor
on the beam
To the side of the boat at right angles, abeam.
on the bow
To the bow of the boat, forward of the beam.
on the quarter
To the stern of the boat, aft of the beam.
on the wind
Sailing close hauled. Sailing toward the wind as much as possible with the wind coming from the bow.
onboard
on the boat
one-design
Any boat built to certain standards or rules so that is like all others in the same class.
onshore wind
A wind blowing onto the land
open
A location that is not sheltered from the wind and seas. An open location would not make a good anchorage.
osmosis
Osmosis is when water penetration occurs through the gel coat and into the laminate below. Osmosis is marked by blistering
out of trim
Sails that are not properly arranged for the point of sail that the boat is on. The sails may be luffing or have improper sail shape, or the boat may be heeling too much. These conditions will slow the boat down.
outboard
On the side of the hull that the water is on. Outboard engines are sometimes just called outboards.
outboard engine
An engine used to power a small boat. Outboard engines are mounted on a bracket aft of the stern of the boat.
outhaul
A line used to tension the foot of a sail, used to maintain proper sail shape.
outrigger
A floatation device attached to one or both sides of the hull to help prevent a capsize.
overall length
The total length of the boat, including any object protruding from the bow or the stern. Also known as LOA.
overboard
In the water outside of the vessel.
overfall
Dangerously steep and breaking seas due to opposing currents and wind in a shallow area.
overhang
The area of the bow or stern which hangs over the water.
overhaul
To sort out mess with the rigging
override
A line that becomes improperly wrapped over itself and fouls a winch.
owner's flag
A boat owner's private pennant.
P
In sail measurements, the longest reach of the mainsail along the mast.
P flag
signal flag known as the "Blue Peter" [blue square in a white the vessel is about to proceed to sea."
pad eye
A small fitting with a hole used to guide a line.
paddle
A stick with a blade in the end of it used to propel a small boat through the water. The act of using a paddle to propel a boat.
painted waterline
A painted line on the side of a boat at the waterline. The color usually changes above and below the waterline as the boat is painted with special antifouling paint below the waterline.
painter
A line attached to the bow of a dinghy and used to tie it up or tow it.
palm
A tool worn on the hand with a thimble shaped structure on it and used when sewing sails.
PAN PAN
An urgent message used on a radio regarding the safety of people or property. A PAN PAN message is not used when there is an immediate threat to life or property, instead the MAYDAY call is used. PAN PAN situations may develop into MAYDAY situations. As with a MAYDAY, PAN PAN messages have priority on the radio channels and should not be interrupted. In the case of a less urgent safety message, such as a hazard to navigation, the appropriate signal to use is SECURITE.
Parachute
Balloon spinnaker.
parachute anchor
A parachute anchor is used to stop drifting
parachute flare
An emergency signal flare that will float down on a parachute after launch, hopefully improving its visibility.
parallax error
Error that can be introduced when not reading an instrument directly from its front, due to the separation of the indicator and the scale being read.
parallel rules
A navigational tool used to move a line on a chart from one location to another without changing its angle, such as when moving a plotted course to a compass rose. Parallel rules are two straight edges that are mechanically connected such that both edges always remain parallel. Lines can then be "walked" across a flat chart.
parallels
Lines of latitude, north and south of the Equator.
parcel
Material wrapped around a line to prevent chaffing.
parrot beak
A clip at the end of a spinnaker pole to hold the guy.
part
fray or break
partners
Supporting structures used to support areas where high loads come through openings in the deck, such as at the mast boot.
passage
A route between points or ports.
patant log
A type of log that uses a counter attached to a rotor on a line which is towed behind the boat to help measure distance and speed.
pax
Abbreviation for Total Passengers
pay off
Allow the boat turn to leeward.
pay out
To let out a line.
peak
The upper corner of a four sided sail or top end of a gaff or spritsail.
pedestal
The column that the wheel is mounted on.
peeling
Changing from one spinnaker to another.
pelorus
A card marked in degrees and having sightings on it that is used to take bearings relative to the ship, rather than magnetic bearings as taken with a compass.
pendant
A small line attached to a mooring chain. Also sometimes called a pennant.
pennant
A small flag, such as can be used for signaling. Flags can be used together to spell words or individually as codes, such as the quarantine flag.
personal floatation device
PFD for short. A device used to keep a person afloat. Also called a life jacket, life preserver or life vest.
phosphorescence
luminescence
pier
A place extending out into the water where vessels may dock. Usually made out of wood or cement.
pile, piling
A pole embedded in the sea bottom and used to support docks, piers and other structures.
pilot
An individual with specific knowledge of a harbor, canal, river or other waterway, qualified to guide vessels through the region. Some areas require that boats and ships be piloted by a licensed pilot.
pilothouse
a small cabin on the deck of the ship that protects the steering wheel and the crewman steering.
piloting
The act of guiding a vessel through a waterway.
pinch
Steering a sailboat too close to the eye of the wind, causing the sails to luff.
pintle
A pin used to attach a stern mounted rudder. The hole that the pin fits is known as a gudgeon.
pitch
A fore and aft rocking motion of a boat. Also see roll and yaw. How much a propeelor is curved. A substance used to seal cracks in wooden planks.
pitch poled
When a boat's stern is thrown over its bow.
pitman
Crewmember who controls the halyards and mast winches and assists the mastman.
planing
A boat rising slightly out of the water so that it is gliding over the water rather than plowing through it.
planing hull
A hull design that is capable of planing.
planing speed
The speed needed for a boat to begin planing.
planking
Wood strips used to cover the deck or hull of a wooden vessel.
plot
To find a ship's actual or intended course or mark a fix on a chart.
plow anchor
Also called a CQR or coastal quick release anchor. An anchor that is designed to bury itself into the ground by use of its plow shape.
plug
A tapered device, usually made from wood or rubber, which can be forced into a hole to prevent water from flowing through it. Plugs should be available to fit every through hull. The act of using something to prevent water entering through a hole.
Pmiz
The longest reach of the mizzen along its mast.
point
To sail as close as possible to the wind. Some boats may be able to point better than others, sailing closer to the wind. The names given to directions on a compass.
point of sail
The position of a sailboat in relation to the wind. A boat with its head into the wind is known as "head to wind" or "in irons". The point of sail with the bow of the boat as close as possible to the wind is called close hauled. As the bow moves further from the wind, the points of sail are called: close reach, beam reach, broad reach, and running. The general direction that a boat is sailing is known as its tack.
polaris
Polaris, the North Star, is visible in the northern hemisphere and indicates the direction of north. In the southern hemisphere the Southern Cross is used to find the direction of south.
pole
A spar. Such as a pole used to position a sail. One of the 2 points around which the earth spins and from which the earth's magnet field is emitted, as in the North and South pole.
poop deck
A boat's aft deck.
pooped
having a wave wash over the stern of the boat
port
The left side of the boat from the perspective of a person at the stern of the boat and looking toward the bow. The opposite of starboard. A place where ships go to dock. A porthole
port tack
Sailing with the wind coming over the port bow.
porthole
A port. A window in the side of a boat, usually round or with rounded corners. Sometimes portholes can be opened, sometimes they are fixed shut. Also see hatches.
position doubtful
A mark of PD made on a chart when plotting a boat's position to indicate that there is reason to doubt that the fix is accurate.
pound
The action of a boat's bow repeatedly slamming into oncoming waves.
pram
A type of dinghy with a flat bow.
preferred channel buoy
Also known as a junction buoy. A red and green horizontally striped buoy used in the United States to mark the separation of a channel into two channels. The preferred channel is indicated by the color of the uppermost stripe. Red on top indicates that the preferred channel is to the right as you return. Also see can and nun buoys.
prevailing winds
The typical winds for a particular region and time of year.
preventer
A line run forward from the boom to a secure fitting to prevent the boom from jibing accidentally when running. If the boat jibes anyway, this can cause the sail to become backwinded.
prime meridian
The 0° longitude line that runs through Greenwich, England.
privileged vessel
The vessel that is required to maintain its course and speed when boats are approaching each other according to the navigation rules. Also known as the stand on vessel.
prop
Slang for propeller.
propane
Also known as LPG (liquid petroleum gas). Propane is a common fuel used for cooking and heating. CNG (natural gas) is considered safer because propane is heavy than air and will sink into the bilge if it leaks, creating the potential for an explosion. Propane is more easily available throughout the world than CNG however, so it is used for most boats outside of North America.
propeller
An object with two or more twisted blades that is designed to propel a vessel through the water when spun rapidly by the boat's engine.
propeller shaft
The spinning shaft from the engine to which the propeller is attached.
protractor
A navigation tool used to measure angles on a chart.
prow
The part of the bow forward of where it leaves the waterline.
pull
in rowing, to row an oar, putting your back into it
pulpit
A sturdy railing around the deck on the bow.
pump out
Removing waste from a holding tank.
purchase
Two or more blocks connected to provide a mechanical advantage when lifting heavy objects.
pushpit
Also called stern pulpit. A sturdy railing around the deck at the stern.
put in
to enter a port or harbor
PVC foam
PVC is the acronynm for Ployvinyl chloride foam. A tough, resilient foam that is not affected by water
Q flag
all yellow signal flag meaning my vessel is healthy and I request free pratique (license to enter port on the grounds that the vessel is disease free).
quadrant
A device connected to the rudder that the steering cables attach to.
quarantine flag
The quebec pennant is flown when first entering a country, indicating that the people on the ship are healthy and that the vessel wants permission to visit the country.
quarter
The side of a boat aft of the beam. There are both a port quarter and a starboard quarter.
quarters
Sleeping areas on the boat.
quartering
Sailing with the wind between the stern and the beam.
quartering sea
A sea which comes over the quarter of the boat.
quay
Also a wharf. A section parallel to the shore for docking and unloading vessels.
queen topsail
small stay sail located between the foremast and mainmast.
quick flashing light
A navigational aid with a light that flashes about once per second.
racon
A radar beacon which emits its signal when triggered by beams from a radar
radar
Radio detection and ranging. An electronic instrument that uses radio waves to find the distance and location of other objects. Used to avoid collisions, particularly in times of poor visibility.
radar arch
An arch to mount the radar, usually at the stern of the boat.
radar clearing line
A radar range to provide a safe distance off when travelling along a coast
radar reflector
An object designed to increase the radio reflectivity of a boat so that it is more visible on radar. Many small boats are made with fiberglass and other materials that do not reflect radar very well on their own.
radio
An instrument that uses radio waves to communicate with other vessels. VHF (very high frequency) radios are common for marine use, but are limited in range. Single side band (SSB) radios have longer ranges.
radio beacon
A navigational aid that emits radio waves for navigational purposes. The radio beacon's position is known and the direction of the radiobeacon can be determined by using a radio direction finder.
radio bearing
A bearing taken with a radio direction finder toward a radio beacon.
radio direction finder
RDF for short. An instrument that can determine the direction that a radio transmission is coming from. The RDF is used with a radio beacon to find a radio bearing to help determine the vessel's position.
radiowaves
Invisible waves in the electromagnetic spectrum that are used to communicate (radio) and navigate (radar, RDF.)
raft
A small flat boat, usually inflatable. To moor with more than boat tied together.
rail
The edge of a boat's deck.
rake
A measurement of the top of the mast's tilt toward the bow or the stern.
range
Distance a boat can travel with its available fuel and supplies. Difference between high and load tides. Two lights ot daymarks that can be aligned behind one another to indicate one is positioned on a line on a chart, typicaly used to guide a boat into a channel.
ratlines
Small lines tied between the shrouds to use as a ladder when going aloft.
reach
Sail with the wind abeam, or almost so.
reaching
Any point of sail with the wind coming from the side of the boat. If the wind is coming from directly over the side, it is a beam reach. If the boat is pointed with its bow more directly into the wind it is a close reach. If the wind is coming from over the quarter, it is called a broad reach.
reciprocal
A bearing 180° from the other. A direction directly opposite the original direction.
red buoy
A nun buoy. A conical buoy with a pointed top, painted red, and having an even number, used in the United States for navigational aids. At night they may have a red light. These buoys should be kept on the right side of the boat when returning from a larger body of water to a smaller one such as a marina. Can buoys are used on the opposite side of the channel. Also see green and red daymarks.
red daymark
A navigational aid used in the United States and Canada to mark a channel. Red square daymarks should be kept on the right when returning from a larger to smaller body of water. Green daymarks mark the other side of the channel. Also see can and nun buoys.
reef, reefing
To partially lower a sail so that it is not as large. This helps prevent too much sail from being in use when the wind gets stronger. A line of rock and coral near the surface of the water.
reef cringles
Reinforced cringles in the sail designed to hold the reefing lines when reefing the sail.
reef knot
Also known as the square knot. This knot is an unreliable knot used to loosely tie lines around the bundles of sail that are not in use after reefing.
reef points
Points where lines have been attached to tie the extra sail out of the way after reefing.
reefing lines
Lines used to pull the reef in the sail. The reef line will pass through reef cringles, which will become the new tack and clew of the reefed sail.
reeve
Leeding a line through a block or other object.
regatta
A series of boat races.
relative bearing
A bearing relative to the boat or another object, rather than a compass direction.
rhumb line
A line that passes through all meridians at the same angle. When drawn on a Mercator chart, the rhumb line is a straight line. However the Mercator chart is a distortion of a round globe on a flat surface, so the rhumb line will be a longer course than a great circle route.
ride out
To weather a storm, either at sea or at anchor.
riding light
Anchor light. A white light displayed from the top of the mast to indicate that the boat is at anchor.
riding sail
Also called a stability sail or steadying sail. Any small sail set to help the boat maintain its direction without necessarily moving, as when at anchor or in heavy weather.
rig
A combination of sails and spars. The act of preparing the rig before sailing.
rigging
The wires, lines, halyards and other items used to attach the sails and the spars to the boat. The lines that do not have to be adjusted often are known as standing rigging. The lines that are adjusted to raise, lower and trim the sails are known as running rigging.
right
To return a boat that is not upright to its upright position.
rigid inflatable
A small inflatable boat that has a solid hull but has buoyancy tubes that are inflated to keep it afloat.
rip current
as in tide rip; water disturbance created by conflicting current and wind
roach
A curve out from the aft edge (leech) of a sail. Battens are sometimes used to help support and stiffen the roach.
Roaring Fourties
A region between 40° south and 50° south where westerly winds circle the earth unobstructed by land.
rocker
The upward curvature of the keel towards the bow and stern.
rode
Anchor rode. A line or chain attached to the anchor.
roll
A side to side motion of the boat, usually caused by waves. Also see pitching and yawing.
roller
a wave
roller furling
A method of storing a sail usually by rolling the jib around the headstay or the mainsail around the boom or on the mast.
roller reefing
A system of reefing a sail by partially furling it. Roller furling systems are not necessarily designed to support roller reefing.
rolling heap
slang expression meaning ocean
rolling hitch
A knot used to attach a line to a spar or similar object.
rope
Traditionally a line must be over 1 inch in size to be called a rope. Cordage purchased from a supplier is called rope. Once installed on a yacht it is referred to as "lines".
row
A method of moving a boat with oars. The person rowing the boat faces backwards, bringing the blade of the oars out of the water and toward the bow of the boat. They then pull the oars through the water toward the stern of the boat, moving the boat forward.
rowboat
A small boat designed to be rowed by use of its oars. Some dinghys are rowboats.
rowlocks
Used as guides for oars.
rub rail, rub strake, rub guard
A rail on the outside of the hull of a boat to protect the hull from rubbing against piles, docks and other objects.
rudder
A flat surface attached behind or underneath the stern used to control the direction that the boat is traveling.
rudder head
The top part of the rudder - the one being actually attached to the tiller.
rudder post
The post that the rudder is attached to. The wheel or tiller is connected to the rudder post.
rules of the road
The rules concerning which vessel has the right of way if there is a possibility of collision between two or more boats.
run
To allow a line to feed freely.
run aground
To take a boat into water that is too shallow for it to float in, i.e: the bottom of the boat is resting on the ground.
runners, running backs, running backstay
Adjustable stays used to control tension on the mast. Temporary backstays used to stabilise the mast and prevent undue flerxing.
running
A point of sail where the boat has the wind coming from aft of the boat. Running can cause the danger of an accidental jibe. Used to describe a line that has been released and is in motion. Sailing with the wind blowing from astern, sailing downwind.
running bowline
A type of knot that tightens under load. It is formed by running the standing line through the loop formed in a regular bowline.
running fix
A fix taken by taking bearings of a single object over a period of time. By using the vessel's known course and speed, the location of the vessel can be found.
running lights
Navigational lights that are required to be used when a vessel is in motion.
running rigging
All lines, halyards and sheets used in controlling sails and spars.
safe course
A determined safe route across dangerous water
safe overhead clearance
A distance that needs to be kept between the mast and overhead electrical lines to prevent electrical arcing.
safe room
All water surface within a certain distance from potential hazards such as the shore
safety harness
A device worn around a person's body that can be attached to jack lines to help prevent a person from becoming separated from the boat.
safety pin
Any pin that is used to prevent a fitting from falling open. A pin used to keep the anchor attached to its anchor roller when not in use.
sail
A large piece of fabric designed to be hoisted on the spars of a sailboat in such a manner as to catch the wind and propel the boat. The act of using the wind to propel a sailboat.
sail shape
The shape of a sail, with regard to its efficiency. In high winds a sail would probably be flatter, in low winds rounder. Other circumstances can cause a sail to twist. Controls such as the cunningham, boom vang, outhaul, traveler, halyards, leech line, sheets, and the bend of the mainmast all can affect sail shape. Also see sail trim.
sail track
A slot into which the bolt rope or lugs in the luff of the sail are inserted to attach the sail. Most masts and roller reefing jibs use sail tracks. Systems with 2 tracks can allow for rapid sail changes.
sail trim
The position of the sails relative to the wind and desired point of sail. Sails that are not trimmed properly may not operate efficiently. Visible signs of trim are luffing, excessive heeling, and the flow of air past telltales. Also see sail shape.
sailboat
A boat which uses the wind as its primary means of propulsion.
sailcloth
A fabric, usually synthetic, used to make sails.
sailing directions
Books that describe features of particular sailing areas, such as hazards, anchorages, etc.
sailing rig
the equipment used to sail a bost, including sails, booms and gaffs, lines and blocks.
salon
also saloon; main social cabin of a boat
sampan
a small boat with a narrow design, originally found in Japan and China
sampson post
A strong post used for to attach lines for towing or mooring.
sand bar
An area in shallow water where wave or current action has created a small, long hill of sand. Since they are created by water movement, they can move and may not be shown on a chart.
sat-phone
A satellite telephone. Sat-phones send and receive their signals directly to and from orbiting satellites and can operate from almost anywhere on earth.
satellite navigation
Navigation using information transmitted from satellites. See Global Positioning System.
scale
Climb.
scandalize
On a gaff rig the sail is made loose footed, the clew is brought forward along the boom and the sail cloth is drawn up in folds along the gaff and mast. From this position the sail is instantly available for use.
scend
The distance that the trough of a wave is below the average water level. With large waves in shallow water the scend is important to help determine whether a boat will run aground.
schooner
A sailboat with two or more masts. The aft mast is the same size or larger than the forward one(s). Also see ketch and yawl.
schooning
To move forward quickly; historic nautical term
scope
Technically, the ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water. Usually six to seven to one for calm weather and more scope in storm conditions.
scopolamine
a drug prescribed for motion sickness
scow
A boat with a flat bottom and square ends.
Screaming Sixties
The area between 60 degrees and 70 degrees latitude noted for exceptionally strong wind, huge seas, and frequent icebergs.
screw
A propeller.
scud
To run before the wind in a storm.
scull
A method of moving a boat by using a single oar at the stern.
sculling oar
a large oar used for propelling a boat by moving from side to side; also used for an emergency rudder
sculling
A technique of “rowing” a dinghy with a single oar
scupper
Drain in cockpit, coaming, or toe-rail allowing water to drain out and overboard. When in toe rail, properly known as "freeing port"
scuttle
To sink a boat.
scuttlebutt
Gossip. People talking about things that may or may not be true, usually about other people or events. The term scuttlebutt evolved from the name of a keg containing water and alcohol that sailors used to gather about before meals.
sea
A body of salt water. A very large body of fresh water.
sea anchor
A drogue designed to bring a boat to a near stop in heavy weather. Typically a sea anchor is set off of the bow of a boat so that the bow points into the wind and rough waves.
sea buoy
The last buoy as a boat heads to sea.
sea cock
A valve used to prevent water from entering at a through hull.
sea kindly
A boat that comfortable in rough weather.
sea level
The average level of the oceans, used when finding water depths or land elevations.
sea room
Room for a boat to travel without danger of running aground.
seagoing
A vessel designed to be able to cross oceans.
seamanship
The ability of a person to motor or sail a vessel, including all aspects of its operation.
seat locker
A storage locker located under a cockpit seat.
seaworthy
A boat or a boat's gear able to meet the usual sea conditions.
secondary port
A port that is not directly listed in the tide tables but for which information is available as a difference from a nearby standard port.
sector
An arc of a circle in which certain types of navigational lights known as sector lights are visible.
sector light
A navigational light that is visible only for a specific sector or arc of a circle, enabling a boat to determine that it lies within that sector. Sector lights might mark the entrance to a channel.
secure
To make fast. To stow an object or tie it in place.
securite
A type of warning message transmitted by radio. Securite messages are used to warn of impending storms, navigational hazards and other potential problems that are not immediately life threatening by themselves. MAYDAY and PAN PAN are used for more immediate problems.
seized
bound together
seizing
Tying two lines, or a spar and a line together, by using a small line.
self bailing
Said of an area, such as the cockpit, that is capable of rapidly draining away any water that may fill the area.
self draining
A locker or other area equipped with a drain capable of allowing any water that may collect in it to leave, such as from wet clothes or equipment.
self steering gear
A device used to keep a sailboat on the same heading relative to the wind without aid of a person. Self steering gear is a mechanical system using a wind vane instead of electrical power as does an autopilot.
self-bailing cockpit
A watertight cockpit with scuppers, drains, or bailers that remove water.
self-tacking
Normally applied to a sail that requires no adjustment other than sheeting when boat is tacked
self-tending
tacks itself
semaphore
A method of signaling using two flags held in position by the signaler.
sentinel
A weight hung from the anchor chain in order to keep the anchor lying as flat as possible to prevent dragging.
separation zone
A region drawn on a chart to separate two lanes that have shipping vessels moving in opposite directions.
serve
To wind small line around a rope to protect it from chaffing and weather.
set
To put an object in place, as in "set the anchor." The direction a current is moving.
sextant
A navigational instrument used to determine the vertical position of an object such as the sun, moon or stars. Used with celestial navigation.
shackle
A metal U-shaped connector that attaches to other fittings with the use of a pin that is inserted through the arms of the U.
shake out
To remove a reef from a sail.
shakedown
An initial trip with a boat to make sure that everything is operating properly.
shank
The long bar part of an anchor. The flukes are at one end of the shank and the stock is at the other.
she
All boats are referred to as female. "She is at anchor." "Her sails are set."
shear pin
A pin attaching one part to another that is designed to break if excessive loads are applied. For example to connect the propeller to the propeller shaft so that the pin can break if the propeller strikes something, preventing damage to the propeller and engine.
sheathing
A covering to protect the bottom of a boat.
sheave
P A wheel used to change the direction of a line, such as in a block or at the top of the masthead.
sheepshank
A knot used to temporarily shorten a line.
sheer
The fore and aft curvature of the deck. A sudden change of course.
sheer strake
The top plank on the side of a wooden boat that follows the sheer of the deck.
sheet
A line attached to the clew of a sail and is used to control the sail's trim. The sheets are named after the sail, as in jib sheets and main sheet.
sheet bend
A type of knot used to tie two lines together.
ship
A large vessel. To take an object on board such as cargo or water. To put items such as oars on the boat when not in use.
ship in seas
take in seas
shipshape
Neat, orderly and ready to use.
shoal
Shallow water. An underwater sand bar that has its top near the surface.
shoaling
A phenomenon occurring as the waves enter a shallow water - their movement forward is slowed down because of the bottom friction, and thus their height increases.
shore
The edge of the land near the water.
shoreline
Where the land meets the water.
short splice
A quickly made splice joining two lines together. A short splice is wider than the original line and will not fit through blocks or fairleads.
shorten
To reef a sail, or drop a sail. To reduce sail area on a boat.
shove off
To push a boat, as from a dock or another boat.
shroud
Part of the standing rigging that helps to support the mast by running from the top of the mast to the side of the boat. Sailboats usually have one or more shrouds on each side of the mast.
shround
The wires holding the mast at the sides.
side lights
Green and red lights on the starboard and port sides of the boat required for navigation at night. Each light is supposed to be visible through an arc of 112.5°, beginning from directly ahead of the boat to a point 22.5° aft of the beam.
sideslip
The tendency of a boat to move sideways in the water instead of along its heading due to the motion of currents or leeway.
sideways force
The part of the force generated by the wind in the sail that moves the boat sideways
sight reduction tables
Tables containing information about the position of the sun, moon, planets and stars. When using celestial navigation these tables help find the position of a boat.
signal halyard
A halyard used to hoist signal flags.
single sideband
A type of radio carried on a boat to transmit long distances.
single-handed
To sail alone; :without crew
sink
To go to the bottom of the water. The act of causing an object to go to the bottom of water.
sister ship
A vessel of a similar design to another.
sked
A position report issue every 6 hours.
skeg
Any flat protrusion on the outside of the hull that is used to support another object such as the propeller shaft or rudder.
skiff
A small boat.
skin
The outside surface of a boat. Usually used when describing a fiberglass or other molded hull.
skipper
The person in charge of a vessel.
slab reefing
Also points reefing, and sometimes jiffy reefing. Reducing the area of the mainsail by partially lowering the sail and re-securing the new foot by tying it to the boom with points or lines attached to the sail.
slack
A line that is loose. To ease a line.
slack water
A period of almost no water movement between flood and ebb tides
slats
battens
slatting
flapping
slide
Also called a lug. Metal or plastic pieces attached to a sail's luff that slide in a mast track to allow easy hoisting of a sail.
sling
Lines used to hoist heavy or awkward objects and the act of using such lines. Ropes used to secure the center of a yard to the mast.
slip
A space between two docks or piers where a boat can be moored.
sloop
A style of sailboat characterized by a single mast with one mainsail and one foresail. Also see cutter.
slot
The opening between the jib and the mainsail. Wind passing through this opening increases the pressure difference across the sides of the mainsail, helping to move the boat forward.
small stuff
Small lines used when whipping and serving.
snap hook
A metal fitting with a arm that uses a spring to close automatically when connected to another object.
snatch block
A block that can be opened on one side, allowing it to be place on a line that is already in use.
snub
To suddenly stop or secure a line.
snubber
a spring line tied from the boat to chain rode, usually near the water's surface. It helps disperse tension forces. It also prevents damage to the boat by ground tackle and can help in the retrieval of the ground tackle in heavy weather. (to reduce the snap of the rode when it stretched out)
soft eye
An eye splice that does not use a protective insert.
soggering
being lazy and unassuming of responsibility
sole
A floor on a boat.
sound
Signals required by navigation rules describing the type of vessels and their activities during times of fog.
sounding
The depth of the water as marked on a chart. Diving, as in a submarine or whale going deeper.
south
One of the 4 cardinal compass points. South is the direction toward the South Pole and is at 180° on a compass card.
south pole
The "bottom" point of the line about which the earth rotates.
south wind, southerly wind
Wind coming from the south.
southern cross
A constellation in the shape of a cross used to determine the direction of the South Pole when traveling in the southern hemisphere.
sou'wester
a wind coming from the southwest
spanker
A gaff-headed sail attached to the mizzenmast.
spar
A pole used as part of the sailboat rigging, such as masts, booms, and gaffs.
spar buoy
A tall buoy used as a navigational aid.
spar poles
most often of wood, aluminum or carbon fiber, used as supports, such as the mast, boom, or spinnaker pole.
spell
To relieve someone when taking turns at a task, such as manning the helm.
spherical buoy
A ball shaped buoy marking a navigational hazard.
spider band
A metal band around a spar with an eye to take the shackles used on the running rigging.
spill the wind
To head up into the wind or loosen a sail, allowing the sail(s) to luff.
spindle buoy
A tall cone shaped navigational buoy.
spinnaker
A large, triangular sail, most often symmetrical, flown from the mast in front of all other sails and the forestay. Used sailing downwind.
spinnaker halyard
A halyard used to raise the spinnaker.
spinnaker pole
Sometimes spinnaker boom. A pole used to extend the foot of the spinnaker beyond the edge of the boat, and to secure the corner of the sail.
spinnaker pole lift
Also spinnaker lift. A line running from the top of the mast, used to hold the spinnaker pole in place.
spitfire
A storm jib. A small jib made out of heavy cloth for use in heavy weather. Sometimes brightly colored.
splashboard
A raised portion of the hull forward of the cockpit intended to prevent water entering.
splice
The place where two lines are joined together end to end.
spreader
Small spars extending toward the sides from one or more places along the mast. The shrouds cross the end of the spreaders, enabling the shrouds to better support the mast.
spring
To begin, as in "to spring a leak."
spring line
Docking lines that help keep the boat from moving fore and aft while docked. The after bow spring line is attached near the bow and runs aft, where it is attached to the dock. The forward quarter spring line is attached to the quarter of the boat, and runs forward, being attached to the dock near the bow of the boat.
spring tide
The tide with the most variation in water level, occurring during new moons and full moons. This is the time of the highest high tide and the lowest low tide. The opposite of a neap tide.
sprit
A spar that supports the peak of a four-cornered sail extending from the mast.
spritsail
A four-sided fore and aft sail set on the mast, and supported by a spar from the mast diagonally to the peak of the sail.
squall
A sudden intense wind storm of short duration, often accompanied by rain. Squalls often accompany an advancing cold front.
square knot
Reef knot. A simple knot that can slip. Often used on sailboats when reefing.
square rigged
A sailboat having square sails hung across the mast.
square sail
A square sail hung from a yard on the mast. Best used when sailing down wind.
SSB
Single sideband radio. A type of radio used on a boat to transmit for long distances.
stability
Ability of a boat to keep from heeling or rolling excessively, and the ability to quickly return upright after heeling.
stability sail
A vertical pole on which flags can be raised.
stall
Air is said to stall when it becomes detached from the surface it is flowing along. Usually air travels smoothly along both sides of a sail, but if the sail is not properly trimmed, the air can leave one of the sides of the sail and begin to stall. Stalled sails are not operating efficiently. To stop moving.
stanchion
A post near the edge of the deck used to support life lines.
stand on vessel
The vessel that is required to maintain its course and speed when boats are approaching each other according to the navigation rules. Also known as the privileged vessel.
standard port
A port for which information is listed in the tide tables. Other ports known as secondary ports have information listed as a difference from the standard port rather that having complete tables.
standing
he part of the line that will carry the load after a knot has been tied in it.
standing part
That part of a line which is made fast.The main part of a line as distinguished from the bight and the end.
standing rigging
The rigging of a boat that does not normally need to be adjusted.
stand-on
To hold a boats course and speed.
starboard
The right side of a boat, from the perspective of a person at the stern of the boat and looking toward the bow. The opposite of port.
starboard tack
A sailboat sailing on a tack with the wind coming over the starboard side and the boom on the port side of the boat. If two boats under sail are approaching, the one on port tack must give way to the boat on starboard tack.
stateroom
Sleeping quarters for the boat's captain or guests.
statute mile
A mile as measured on land, 5280 feet or 1.6 kilometers. Distances at sea are measured as nautical miles.
stay
Lines running fore and aft from the top of the mast to keep the mast upright. Also used to carry some sails. The backstay is aft of the mast and the forestay is forward of the mast.
staysail
A triangular sail similar to the jib set on a stay forward of the mast and aft of the headstay.
steadying sail
Also stability sail or riding sail. Any small sail set to help the boat maintain its direction without necessarily moving, as when at anchor or in heavy weather.
steaming light
Also known as a masthead light. The steaming light is a white light that is visible for an arc extending across the forward 225° of the boat. When lit the steaming light indicates that a vessel under power, including sailboats with engines running. Steaming lights are usually located halfway up the mast rather than at the top.
steep seas
Tall and short waves caused by water current and wave directions being opposite to the direction of the wind.
steerage way
In order for the rudder to be able to properly steer the boat, it must be moving through the water. The speed necessary for control is known as steerage way.
stem
The forward edge of the bow. On a wooden boat the stem is a single timber.
step
A fitting for the bottom of the mast (mast step.) The act of placing the foot of the mast in its step andnraising the mast.
stepped
A mast that is in place is stepped. Where the mast is stepped, as in keel stepped or deck stepped.
stern
The aft part of a boat. The back of the boat.
stern light
A white running light placed at the stern of the boat. The stern light should be visible through an arc of 135°, to the rear of the boat.
stern line
A line running from the stern of the boat to a dock when moored.
stern pulpit
Pushpit. A sturdy railing around the deck at the stern.
stern quarters
The aft corners of the hull
sternway
Making way in reverse.
stiff
A boat that resists heeling.
stock
A crossbeam at the upper part of an anchor.
stopper
A mechanical device or knot used to keep a rope from running.
stopper knot
A knot used in the end of a line to prevent the end from running through a block or other narrow space. Stopper knots prevent a line that slips from unthreading itself and getting lost.
stores
Supplies on a boat.
storm jib
Sometimes called a spitfire. A small jib made out of heavy cloth for use in heavy weather. Sometimes brightly colored.
storm sail
The storm jib and storm trysail. Small sails built from heavy cloth for use during heavy weather.
storm trysail
A very strong sail used in stormy weather. It is loose footed, being attached to the mast, but not the boom. This helps prevent boarding waves from damaging the sail or the rigging.
stow
To put something away.
strake
On wooden boats, a line of planking running from the bow to the stern along the hull.
strike
To lower.
strum box
A strainer in the bilge so that the bilge pump doesn't get clogged.
studding out a sail
extending a sail using a whisker pole
stuffing box
A fitting around the propeller shaft to keep the bearing lubricated and to keep water out of the boat.
sump pump
small pump for shower drainage
superstructure
Cabins and rooms above the deck of a ship.
surf
The breaking waves and resulting foam near a shore. The sport od ridingn waves on a board.
surge
rising and falling of the sea, usually due to wave action
survey
An inspection of a boat to determine its condition.
surveyor
A person who is qualified to inspect a boat in order to determine its condition.
swab
A mop made from rope. The act of susing such a mop.
swallow
The place between the sheave (roller) and housing of a block, through which the line is run.
swamp
To fill with water.
sweat and tail
Sweat is the act of hauling a halyard to raise a sail or spar done by pulling all slack outward and then downward. Tail is controlling, coiling, and securing the runnning end of the halyard.
swell
Large smooth waves that do not crest. Swells are formed by wind action over a long distance.
swim platform
A platform, usually on the transom, allowing swimmers to easily climb back onto a boat.
swing a compass
The act of checking compass readings against known headings in order to determine the compass error.
swinging bridge
A bridge that swings away from the waterway so that boats may pass beside it.
swinging circle, swinging room
The distance a boat can move around its anchor. Swinging room is important because if other boats or objects are within a boat's swinging circle they may collide.
swivel
A rotating fitting used to keep a line from tangling.
tabernacle
A hinged support for the bottom of a mast so that the mast can be lowered easily when passing under bridges.
tachometer
A gauge that measures engine revolutions per minute.
tack
The lower forward corner of a triangular sail. The direcftion that a boat is sailing with respect to the wind as in port tack or starboard tack. To change qa boat's direction, bringing the bow through the eye of the wind.
tack hook
A snap used to hold the tack of the jib at the bow, while the sail is raised.
tack pin
A pin used to secure the tack of a triangular sail at the mast.
tacking
To change a boat's direction, bringing the bow through the eye of the wind. To tack repeatedly, as when trying to sail to a point up wind of the boat.
tackle
Lines used with blocks in order move heavy objects.
taffrail
A rail around the stern of a boat.
taffrail log
Walker log; a propeller drawn through the water that operates an odometer on the boat registering the distance sailed
tail
The end of a line. A line attached to the end of a wire to make it easier to use. To gather the unused end of a line neatly so that it does not become tangled.
take in
To remove a sail. To add a reef to a sail.
tall buoy
Also called a Dan buoy. A float with a flag at the top of a pole. Used to mark a position such as for a race or a man overboard.
tang
A metal fitting on the mast that the spreaders are attached to.
telltales
Short pieces of yarn attached to the shrouds, or the sails. At the shrouds they indicate the direction of the wind (the apparent wind), and at the sails they help to check the air flow over the sail, so that proper trimming is easier.
tender
A small boat used to ferry people and supplies between a larger boat and the shore. See dinghy. Used to describe a boat that heels easily.
tenon
The bottom of the mast, with a shape designed to fit into the mast step.
the hard
land
thimble
A metal fitting used to strengthen an eye splice (loop) made in a rope or wire.
throat
The forward upper corner of a four cornered sail known as a gaff rigged sail.
through hull
Fittings attached through the hull to which a sea cock and hose, a transducer, or other device is attached. Through hulls are used to expel waste water, such as from a sink, to let sea water in, such as for engine cooling, and to allow placement of sensors such as depth gauges. A sea cock is attached directly to the through hull before any hoses are attached so that the flow of water can be easily shut off if the hose fails. Plugs should be available to force into a through hole in case the through hole fails. Transducers should be equipped with caps to place over the hole should the transducer itself need to be removed.
thwart
A transverse structural member in the cockpit. In small boats, often used as a seat.
thwartships
Also athwartships. Across the width of a boat.
tidal atlas
Small charts showing tidal stream directions and rate of flow.
tidal current
Also called tidal stream. The flowing of water caused by the rising and lowering tidal waters.
tidal drift
Strength of the tidal drift
tidal range
The difference of a tide's high and low water levels.
tidal stream
The flow of water caused by rising and lowering tides.
tide
The predictable, regular rising and lowering of water in some areas due to the pull of the sun and the moon. Tidal changes can happen approximately every 6 or 12 hours depending on the region. To find out the time and water levels of different tides, you can use tide tables for your area. The period of high water level is known as high tide and the period of low water level is known as low tide. In the Bay of Fundy, the tidal range exceeds 40 feet (13 meters.)
tide tables
Tables containing information about the time of the high and low tides and the water level to be expected at that time.
tiller
A spar attached to the rudder by the rudder head, used to control the direction of the boat. Another possibility for steering mechanism is a steering wheel.
tiller bar
A device linking the two tillers of a catamaran
tiller extension
Also hiking stick. An extension to the tiller allowing the helmsman to steer while hiking. Commonly found on racing boats, they can help improve visibility or stability.
time zone
Regions of about 15° of longitude around the world where time is measured on a local scale. Each time zone keeps time slightly differently so that at 12:00 noon the sun will be high in the sky. For example at noon in England it is midnight in New Zealand. If New Zealanders kept their clocks set to the English time zone, it would be very dark at noon!
toe rail
A small rail around the deck of a boat. The toe rail may have holes in it to attach lines or blocks. A larger wall is known as a gunwale.
tonnage
The weight or displacement of a ship.
top heavy
A boat that has too much weight up high. This can adversely affect the boat's stability.
top mast
A mast on top of another mast.
topmark
A mark on the top of a navigational buoy or daybeacon.
topmast
a second spar carried at the top of the fore or main mast, used to fly more sail.
topping lift
A line running from the end of the boom to the top of the mast used to keep the boom from falling when the sail is not set.
topsail
A triangular sail set above the gaff on a gaff rigged boat.
topsides
The sides of the hull above the waterline and below the deck.
torch
old sailing term for lantern that throws out a beam of light. Now it also can refer to a flashlight.
tow
To pull a boat with another boat, such as a tugboat towing a barge.
towing light
Running lights that should be used by boats when towing to indicate that a tow is in progress.
track
The path that a vessel is taking. A guide in the mast or other spar that accepts lugs to each sail. A rail to which a sliding car is attached for easy adjustment of the position of blocks and lines.
trade wind
Winds in certain areas known for their consistent strength and direction. Trade winds are named because of their reliability, allowing for planned voyages along the routes favored by those winds.
trailing
dragging, as in "dragging a line"
trailing edge
The aft edge of a sail, more commonly called the leech.
training run
Not quite a run, but about 10 degrees off the course of an actual run
trampoline
The space on a catamaran, usually made of some kind of mesh, located between the two hulls. It's a place for the crew (like a cockpit on dinghies and cruisers).
transducer
An electronic device that uses sound waves to collect information such as water depth and vessel speed, usually attached to a through hull. The transducer then converts that information to electrical signals that can be used by electronic displays in the cockpit.
transit
Also called a range. Two navigational aids separated in distance so that they can be aligned to determine that a boat lies on a certain line. Transits can be used to determine a boat's position or guide it through a channel.
transom flaps
Flaps in the transom that allow water to run off the boat
transom
The flat area of the hull, at the stern of a boat.
trapeze
A belt and line used to help a crew hike out beyond the edge of a boat to counteract the boat's heel. Usually used on small vessels for racing.
traveler
A track or rod with an attached block, allowing more controlled adjustment of a sail's sheet. The traveler allows better control of the sail's shape.
triatic stay
A stay leading from one mast, such as the main mast to another, such as the mizzen mast.
tricolor light
A running light allowed on some sailboats instead of the normal bow and stern lights. The tricolor light contains the red and green side lights and the white stern light in a single fitting that is attached to the top of the mast.
trim
To haul in on a sheet to adjust the sail trim. A properly balanced boat that floats evenly on its waterline. Improperly trimmed boats may list or lie with their bow or stern too low in the water.
trim tab
An adjustable section of the rudder that allows the rudder to be corrected for lee helm or weather helm.
trimaran
A three hulled boat.
trimmer
The person controlling the shape of the sails on a boat. It is usually the crew on a dinghy, and a different person for each sail on larger boats.
trip line
A line attached to the end of an anchor to help free it from the ground.
Tropic of Cancer
A line 23 degrees, 27 minutes north of the equator. On June 21 the sun is directly above the Tropic of Cancer, at all other times the sun is further south.
Tropic of Capricorn
A line 23 degrees, 27 minutes south of the equator. On December 22 the sun is directly above the Tropic of Capricorn. At all other times the sun is further north.
tropics
The region around the equator between the Tropic of Cancer and the Tropic of Capricorn. The tropics are known for their warm weather.
trough
The bottom of a wave, the valley between the crests.
truck
A cap for the top of the mast.
true course
The course of a boat after being corrected for magnetic deviation and magnetic variation.
true north
Geographic north. Toward the North Pole.
true wind
The speed and direction of the wind. The motion of a boat will cause the wind to appear to be coming at a different direction and speed, which is known as apparent wind
trunk
The place that the centerboard or daggerboard retracts into.
trunnion hoop
A hinged fitting at the top of a mast to hold another mast above it.
trysail
A very small sail, used in a very heavy weather instead of a mainsail.
tugboat
A small powerful boat used to help move barges and ships in confined areas.
tune
To adjust the standing rigging or other equipment to make a boat perform better.
turn turtle
For a boat to turn completely over such that its mast is pointing down instead of up.
turnbuckle
A metal fitting that is turned to tighten or loosen the tension on standing rigging.
turning circle
The distance required for a boat to turn in a complete circle.
turtle
A bag in which a spinnaker or other large sail can be stowed with the lines attached so that it can be rapidly raised.
twine
Small line used for whipping other light duties.
twing
Similar to a Barber hauler, a twing adjusts the angle of sheeting.
two half hitches
A knot with two half hitches (loops) on the standing part of the line.
typhoon
A strong tropical revolving storm of force 12 or higher in the southern hemisphere. Typhoons revolve in a counterclockwise direction. In the northern hemisphere these storms revolve clockwise and are known as hurricanes.
una rig
Boat rigged with a single sail.
under bare poles
Having no sails up. In heavy weather the windage of the mast and other spars can still be enough to move the boat.
under the lee
On the lee side of an object, protected from the wind.
under way
A vessel in motion is under way.
undertow
Strong offshore current extending to the shore.
unfurl
To unfold or unroll a sail. The opposite of furl.
union jack
A small flag representing the nationality of the boat.
upwind
Object nearer the direction the wind is coming from than the observer.
uphaul
A line or wire used to control the height of a spinnaker pole
v bottom
A hull with the bottom section in the shape of a "V".
vane
A weathercock, A wind direction indicator.
vang
A device, usually with mechanical advantage, used to pull the boom down, flattening the sail.
variable pitch
A type of propeller that has adjustable blades for varying speeds or directions, and may be able to reduce drag when under sail.
variation
Magnetic variation. The difference between magnetic north and true north, measured as an angle. Magnetic variation is different in different locations, so the nearest compass rose to each location on a chart must be used.
v-berth
usually the forward berth of the boat, located in the bow
vector
A line drawn to indicate both the direction and magnitude of a force, such as leeway or a current.
veer
Turn away from the wind. A wind change clockwise. To veer a cable is to let it out more.
velocity made good
Also VMG. Actual boat speed after adjusting for such factors as current and leeway.
ventilator
Construction designed to lead air below decks. May have a cowl, which can be angled into or away from the wind; and may be constructed with baffles, so that water is not allowed below, as in Dorade ventilator.
vertical clearance
The distance between the water level at chart datum and an overhead obstacle such as a bridge or power line.
very quick flashing
A navigational aid with a light that flashes between 80 and 159 times per minute. Usually around twice per second.
vessel
Any kind of boat, ship or yacht
VHF
Very High Frequency radio waves. A radio that transmits in the VHF range.
victuals
food
visual bearing
A bearing taken by visually observing the location of known landmarks.
visual fix
A fix taken by visually observing the location of known landmarks.
vittles
victuals
VMG
Velocity made good. Actual boat speed after adjusting for such factors as current and leeway.
wake
Moving waves, that a boat leaves behind it, when moving through water.
warp
Heavier lines (rope or wire) used for mooring, anchoring and towing. May also be used to indicate moving (warping) a boat into position by pulling on a warp.
watch
A division of crew into shifts.
waterline
A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).
waterline length
The length of the boat at the waterline.
waterlogged
Completely filled with water.
watertight hatch
Watertight doors. In the event of a hull breach, the hatches can be closed to seal off compartments on the affected portion of the boat.
waterway
A river, canal or other body of water that boats can travel on.
way
The progress of a boat. If a boat is moving it is considered to be "making way."
waypoint
A specific location as defined by GPS, the Global Positioning System.
wear
Sailing in a circle to change direction downwind to aviod a gybe. May also mean turning away from the wind, as in veer.
weather helm
The tendency of a boat to head up toward the eye of the wind. The opposite of lee helm.
weather shore
The shore if wind blows strongly offshore
weigh
To raise, as in to weigh anchor.
well
A chamber that houses a boats daggerboard.
west
One of the 4 cardinal compass points. West is at 270° on a compass card.
west wind, westerly wind
Wind coming from west.
wet locker
A locker equiped with a drain so that wet clothes can be stored in it without damaging other objects in the boat.
wetted surface
The amount of area of the hull, keel, rudder, and other objects that is under water.
wharf
Also a quay. A section parallel to the shore for docking and unloading vessels.
wheel
One of two methods used to steer a boat. A wheel is turned in the direction that the helmsman wants the boat to go. On smaller boats a tiller is usually used, which steers in the opposite manner.
whip
To bind the strands of a line with a small cord.
whisker pole
A short spar, normally kept stowed, which may be used to push the clew of a jib away from the boat when the boat is running downwind.
whistle buoy
A navigational buoy with a whistle.
wide berth
To avoid something by a large distance.
widow-maker
a term for the bowsprit (many sailors lost their lives falling off the bowsprit while tending sails).
winch
mechanical device for hauling in a line
winch pedestal
An upright winch dri ...
wind rose
a diagram usually shown on pilot charts that indicates the frequency and intensity of wind from different directions for a particular place
wind scoop
A funnel used to force wind in a hatch and ventilate the below decks area.
windage
The amount of a boat, sail or other object that the wind can push on.
windlass
A mechanical device used to pull in cable or chain, such as an anchor rode.
window
A transparent portion of a jib or mainsail.
windward
In the direction of the wind. Opposite of leeward.
wing and wing
A method of running before the wind with two sails set. Usually the mainsail on one side and a headsail on the other, or one headsail on each side.
wishbone
A boom composed of two separate curved pieces, one on either side of the sail. With this rig, sails are usually self tending and loose-footed.
work boat
A boat used for earning a living.
working sails
The sails used on a particular sailboat in normal weather conditions.
working sheet
The sheet that is currently taught and in use to control a sail. The opposite of the lazy sheet.
X
A mark on a pirate's treasure chart that is supposed to indicate where the treasure is.
xylocaine ointment
A recommended ointment to have on board in emergency medical kits for burns
yacht
A vessel larger than a boat and smaller than a ship. A sailboat used for pleasure, not a working boat. From the Dutch word "Jaghd"
yankee
a fore-sail flying above and forward of the jib, usually seen on bowsprit vessels.
yar
fit and beautiful (boat)
yard
A spar attached to the mast and used to hoist square sails.
yard arm
The end of a yard.
yaw, yawing
to turn from side to side in an uneven course
yawl
a two-masted boat, with the smaller, after mast stepped behind the stern post.
zenith
The point when the celestial sphere is directly overhead
zephyr
A gentle breeze
zigzagging
Alternating tacks on approximately equal distances.
zincs
Zinc plates attached to the hull to minimize electrolysis (and ultimate failure) of the metal in the rudder and other areas
zulu
coordinated universal time
