Glossary

AJAX progress indicator
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  • 0

  • 0 - Zero
    Number Pennant Zero (0)
  • 1

  • 1 - Wun
    Number Pennant One (1)
  • 2

  • 2 - Too
    Number Pennant Two (2)
  • 3

  • 3 - Tree
    Number Pennant Three (3)
  • 4

  • 4 - For er
    Number Pennant Four (4)
  • 5

  • 5 - Fife
    Number Pennant Five (5)
  • 6

  • 6 - Six
    Number Pennant Six (6)
  • 7

  • 7 - Seven
    Number Pennant Seven (7)
  • 8

  • 8 - ait
    Number Pennant Eight (8)
  • 9

  • 9 - nin er
    Number Pennant Nine (9)
  • a

  • Aback
    A foresail when against the wind, used when tacking to help the vessel turn
  • Abaft
    Toward the stern, relative to some object ("abaft the fore hatch")
  • Abate
    The true wind abates or moderates when it blows less strongly than before
  • Abeam
    To the side, more or less at right angles to the vessel
  • Adrift
    A vessel not attached to the sea bed
  • Afloat
    A vessel floating or at sea
  • Aft
    Towards the stern (back) of a vessel
  • After Deck
    The part of a ship's deck past amidships toward the stern
  • Aground
    A Vessel resting on the bottom (shore or reef) of a body of water, ‘ran aground’ (usually involuntarily)
  • Ahead
    Directly in front of your vessel
  • Ahoy!
    Shout to attract the attention of another vessel
  • Air Cushioned Vessel
    A Hovercraft
  • AIS
    An automatic tracking system used on ships and by vessel traffic services (VTS). AIS works over VHF and supplements marine radar, which continues to be the primary method of collision avoidance for water transport
  • Alee
    To leeward
  • Almanac
    Annual publication containing information on Ports, Tide tables and much, much more.
  • Aloft
    Up the mast or in the rigging
  • Alongside
    Mooring side on to a dock or pontoon
  • Alpha
    Phonetic alphabet letter A
  • Amidships
    The centre part of the vessel
  • Anchor
    A hook or grapple device use to secure a vessel to the seabed, usually temporarily.
  • Anchor Aweigh
    The point at which and anchor breaks out (is broken out) of the sea bed when it is being hauled in. Shouts ‘Anchor’s aweigh’
  • Anchor Ball
    Round black shape hoisted in forepart of vessel to show it is anchored.
  • Anchor Buoy
    A small buoy attached by a rope to the anchor which enables you to see where your anchor is lying on the sea bed
  • Anchor Cable
    Chain or rope connection between a vessel and her anchor
  • Anchor Light
    An all-round white light to indicate a vessel is at anchor
  • Anchor Locker
    A locker where the anchor and anchor chain and rope are stowed
  • Anchor Roller
    A roller at the bow of the vessel which the cable is passed over when at anchor
  • Anchorage
    A good (usually charted) location to drop anchor
  • Antifoul
    Paint applied to hull below waterline to discourage dirt and wildlife attaching and slowing your progress. Has environmental implications
  • Apparent Wind
    The wind we feel. If the true wind is hitting the boat on the beam or in front of the beam the apparent wind will be situated between the boat wind and the true wind. It is the direction of the apparent wind that determines the angle at which we can point the boat. If the true wind is hitting(...)
  • Ashore
    On the land; or aground
  • Astern
    The area behind the stern (back) of the vessel
  • Automatic Identification System
    An automatic tracking system used on ships and by vessel traffic services (VTS). AIS works over VHF and supplements marine radar, which continues to be the primary method of collision avoidance for water transport
  • Autopilot
    Equipment that allows the boat steer a course automatically using either compass bearing or a course relative to wind direction
  • Auxiliary
    A term for a saying a boat that has auxiliary power, i.e. an engine
  • Awash
    Level with the surface of the water which just washes over an object
  • b

  • Baby Stay
    An inner forestay
  • Back
    Wind: it backs when it shifts to blow from a direction that is further anticlockwise. Sail: is backed when it is sheeted or held to windward so that the wind strikes it on the side which is normally to leeward
  • Back Stay
    The backstay runs from the top of the mast to the stern of the vessel. The backstay supports the mast and in some cases can be adjusted to change the bend in the mast which aids sail trim. On yachts with very large mainsails which would interfere with the backstay, running backstays would be fitted.
  • Bail
    To remove water from the bilges or cockpit
  • Bailer
    A utensil used to bail water out of a boat
  • Ball
    A black signal shape displayed when a vessel is at anchor by day
  • Ballast
    Additional weight placed low in the hull to improve stability
  • Bar
    A shallow area (shoal) close by a river mouth or harbour entrance or A measure of barometric pressure usually noted as 1000 millibars
  • Bare Poles
    No sails are set and boat is driven by the force of the wind on the spars and rigging
  • Bathing Platform
    Purpose-built area which sits at water level when the vessel is stopped. Allows easy access to and from the water. Not to be used while the vessel is underway (moving).
  • Batten
    Stiff strip used to support the roach of a sail, enabling larger sail area and better shape.
  • Batten Pocket
    A pocket on the leech of a mainsail to contain the batten
  • Beach
    To run a vessel ashore deliberately
  • Beacon
    Usually lite, a fixed aid to navigation attached directly to the earth’s surface.
  • Beam
    The widest part of the boat (generally the middle) is referred to as the BEAM.
  • Beam Reach
    A point of sailing with the wind roughly at right angles to the fore and aft
  • Bear Away
    To alter course away from the wind
  • Bearing
    The direction of an object from an observer
  • Bearings
    Bearings and courses are given in a 3 figure notation i.e. 090°
  • Beating
    Sailing towards the wind with the sails hauled in tight
  • Beaufort Scale
    A scale of measurement of the force of the wind
  • Below Deck
    Beneath the deck
  • Bermudan Rig
    A triangular mainsail, without any upper spar, which is hoisted up the mast by a single halyard attached to the head of the sail. This configuration, introduced to Europe about 1920, allows the use of a tall mast, enabling sails to be set higher where wind speed is greater.
  • Berth
    A place where a vessel can be tied up;  A sleeping place on a vessel; To give an obstruction wide clearance by keeping well clear
  • Bi-colour Light
    Combined red (port) and green (starboard) light positioned on the bow
  • Bight
    A loop in rope or line—a hitch or knot tied on the bight is one tied in the middle of a rope, without access to the ends.
  • Bilge Pump
    Used to empty unwanted water from the vessel. Can be automatic, manual and mobile and are usually positioned to collect the water from the lowest part of the bilges.
  • Bilges
    The compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel.
  • Binnacle
    The stand on which the ship's compass is mounted, usually in front of the wheel. May also carry navigation instruments.
  • Block
    A pulley or set of pulleys.
  • Boat Hook
    A pole with a hook on the end, used to reach into the water to catch buoys or other floating objects.
  • Boat Wind
    Just like running down the road or cycling downhill you will feel the wind on your face; boat wind is just the same. As the boat moves through the water she will be travelling forward so you will feel the effect on your face. Boat wind travels straight down the middle of the boat whichever(...)
  • Bollard
    Strong fitting, firmly bolted to the deck, to which mooring lines are made fast. Large bollards are on quays, piers and pontoons
  • Boom
    The boom is attached to the mast by a fitting called the gooseneck. The other end of the boom holds the clew in place, which is controlled by the outhaul. The position of the boom can be adjusted by pulling or releasing the mainsheet.
  • Boom Out
    On a run to thrust the Genoa out to windward so that it fills with wind
  • Bow
    The front portion of a vessel
  • Bow line
    Rope used to secure bow of the vessel alongside.
  • Bow Spring
    Line used to prevent a vessel from moving aft when attached to a pontoon
  • Bowline
    A knot tied in the end of a line to make a loop that will neither slip nor jam
  • Bowsprit
    A spar projecting from the bow used to attach the tack of some headsails, particularly asymmetric spinnakers
  • Bravo
    Phonetic alphabet letter B
  • Breakwater
    A structure constructed on a coast as part of a coastal defense system or to protect an anchorage from the effects of weather and longshore drift.
  • Broach
    When a sailing vessel loses control of its motion and is forced into a sudden sharp turn, often heeling heavily and in smaller vessels sometimes leading to a capsize. The change in direction is called broaching-to. Occurs when too much sail is set for a strong gust of wind, or in circumstances(...)
  • Broad Reach
    Sailing with the wind on the quarter
  • Bulkhead
    An upright wall within the hull of a ship. Particularly a watertight, load-bearing wall.
  • Bung
    Softwood device for plugging holes in vessel or failed seacocks.
  • Bunk
    A built-in sleeping place
  • Buoy
    A floating object used to indicate the position of a channel, wreck, danger, etc., or the position of an object on the seabed
  • Buoyancy Aid
    A life-preserver to help a person float if he falls in, less effective than a lifejacket
  • Burgee
    A triangular flag worn at the masthead
  • c

  • Cabin
    The sheltered area in which the crew live and sleep
  • Cable
    A measure of length or distance. Equivalent to (UK) 1/10 nautical mile, approx. 600 feet or 183 meters or A large rope
  • Call Sign
    Is a unique 5 character, alpha-numeric code, assigned to a vessel by its national licensing authority.  Its primary use is for identification of a vessel over the marine VHF radio, particularly in the event of a distress situation.
  • Capsize
    When a ship or boat overturns, exposing the keel or centre board
  • Cardinal Mark
    Buoy or pillar placed at North, East, South or West side of an obstruction to warn vessels away.
  • Cast Off
    To let go a rope or line
  • Catamaran
    A vessel with two hulls.
  • Chafing
    Wear on line or sail caused by constant rubbing against another surface
  • Chain Plate
    A fitting which is bolted to the hull, to which the shrouds are attached
  • Chandler
    A shop which sells nautical equipment
  • Channel
    A waterway through shoals, rivers or harbours
  • Charlie
    Phonetic alphabet letter C
  • Chart
    Printed map giving many details about the area covered by water and details about the adjacent land
  • Chart Datum
    Reference level on charts and for use in tidal predictions. It is approximately the lowest the tide is ever expected to fall because of astronomical phenomena, also known as Lowest Astronomical Tide (LAT)
  • Chart Table
    Used for preparing passage plans and noting position during your voyage. Around the chart table you will find electronic navigation equipment, electrical switches and the VHF/DSC radio.
  • Charted Depth
    The depths shown on the chart are the depths of the seabed below Chart Datum and are therefore the least depth expected at that point in normal circumstances.
  • Chartplotter
    A device used in marine navigation that integrates GPS data with an electronic navigational chart (ENC)
  • Chine
    A line formed where the sides of a boat meet the bottom. Soft chine is when the two sides join at a shallow angle, and hard chine is when they join at a steep angle.
  • Chop
    Short choppy seas
  • Chronometer
    A timekeeper accurate enough to be used to determine longitude by means of celestial navigation.
  • Clear
    To disentangle a line; To avoid a danger or obstruction; Improved weather
  • Clearance
    The distance between top of mast and bridge or bottom of keel and seabed.
  • Cleat
    Cleats are primarily used for attaching mooring lines to your vessel. The mooring lines are then secured to another yacht, pontoon or harbour wall.
  • Clew
    The after lower corner of a sail to which sheets are fitted
  • Clew Outhaul
    The line which tensions the foot of the sail
  • Close Hauled
    Cleats are primarily used for attaching mooring lines to your vessel. The mooring lines are then secured to another yacht, pontoon or harbour wall.
  • Coachroof
    The part of the cabin that is raised above the deck to provide height in the cabin
  • Coaming
    The raised edge of a hatch, cockpit or skylight to help keep out water.
  • Coastguard
    The organisation responsible for search and rescue operations in UK waters
  • Cocked Hat
    In navigation the triangle formed when three position fixes fail to meet at a single point
  • Cockpit
    A space lower than deck level in which the crew can sit or stand
  • COG
    The actual course your vessel is tracking over the seabed
  • Collision Course
    The course of a vessel which, if maintained relative to that of another would result in a collision
  • Companionway
    The companionway is the access point to below decks. The companionway should be kept clear at all times.
  • Companionway Steps
    Leading down from the deck to the saloon the companionway steps can become slippery when wet. When descending the steps always face them, as this will prevent a nasty fall.
  • Compass
    The compass is a crucial instrument and one you will learn to use without even thinking about it. The compass needle points to magnetic North.
  • Compass Rose
    A circle printed on a chart representing the true compass and graduated clockwise from 000° to 359°
  • Constrained by Draught
    Large, deep vessel confined by narrow channel and unable to manoeuvre easily
  • Contour Line
    Depths are all measured in metres from lowest astronomical tide (LAT). Points of equal depth may be connected by a solid black line to give a continuous contour line.
  • Course
    The direction in which the vessel is being, or is to be, steered
  • Course Over Ground (COG)
    The actual course your vessel is tracking over the seabed
  • Course to Steer
    Course given to helm having taken account of Tidal stream and Leeway.
  • Courtesy Ensign
    The national flag of a country being visited by a foreign boat, it should be flown in the starboard spreader
  • Courtesy Flag
    National flag or ensign of country you are visiting which should be flown from starboard spreaders or flagstaff. It is a courtesy not a legal obligation, but if you like a warm welcome, fly one!
  • CQR
    A patented anchor (Coastal Quick Release) with good holding power
  • CQR Anchor
    A patented anchor (Coastal Quick Release) with good holding power
  • Crew
    Everyone on board other than the skipper and passengers
  • Cringle
    A rope loop, usually at the corners of a sail, for fixing the sail to a spar. They are often reinforced with a metal eye.
  • Cross Track Error
    The distance your vessel is off your intended course.
  • CTS
    Course given to helm having taken account of Tidal stream and Leeway.
  • Current
    Horizontal movement of water in the oceans which is generally wind-driven. Currents are usually continuous and vary with the seasons
  • d

  • Danbuoy
    A temporary mark to indicate position or a man overboard. A flag flown from a spar passing through a float weighted at the bottom
  • Davit
    A crane, often working in pairs and usually made of steel, used to lower things over the side of a ship, including launching a lifeboat over the side of a ship. Sometimes seen on yachts for carrying the tender
  • Dead Reckoning
    The vessel's approximate position derived solely from the compass course steered and distance run according to the log. It makes no allowance for leeway or tidal drift.
  • Deck Log
    A book in which all matters concerning navigation are entered
  • Delta
    Phonetic alphabet letter D or a type of anchor
  • Depression
    A low pressure weather system
  • Depth
    An electronic depth-finding instrument or the amount of water at a given time
  • Deviation
    The deflection of the needle of a magnetic compass caused by the proximity of ferrous metals, electrical circuits or electronic equipment
  • Diaphone
    A powerful two-tone fog signal with a grunt at the end.
  • Digital Selective Calling
    Is the process of sending a digital message using a VHF transmission. It is used to send and listen for distress signals in maritime situations and is a core part of the Global Maritime Distress Safety System.
  • Dinghy
    A type of small boat, often carried or towed as a ship’s boat by a larger vessel. Also small open sailing boats often used for racing and training
  • Dip the Ensign
    To lower the ensign briefly as a salute.  It is not re-hoisted until the vessel saluted has dipped and re-hoisted hers in acknowledgement
  • Direction of Buoyage
    Indicates which side the Port and Starboard marks will be found if you are navigating in a channel
  • Directional Light
    A light illuminating a sector or very narrow angle and intended to mark a direction to be followed.
  • Displacement
    The weight of a vessel defined as the weight of water displaced by that vessel
  • Displacement Vessel
    A displacement hull moves (pushes apart) the water it passes through. Hence displacing the water.
  • Distance
    The distance covered over the ground having made allowance for tidal stream and leeway.
  • Distance to Waypoint
    Distance to travel until your reach your next waypoint.
  • Dividers
    Instrument with two points used to measure distances and assist chart work.
  • Dodger
    Screen fitted to give the crew protection from wind and spray
  • Dolphin
    A mooring post or group of piles
  • Double Up
    To put out extra mooring lines when a storm is expected
  • Douse
    To lower a sail; To extinguish a light quickly
  • Downhaul
    A rope or line with which an object such as a spar or sail is pulled down
  • Downstream
    The direction towards which the stream flows
  • Downwind
    Direction to leeward
  • DR
    The vessel's approximate position derived solely from the compass course steered and distance run according to the log. It makes no allowance for leeway or tidal drift.
  • Drag
    The anchor drags when it fails to hold and slides over the seabed
  • Draught
    The vertical distance from the lowest part of the keel to the waterline
  • Dredger
    A vessel for dredging a channel
  • Drift
    To be carried by the tidal stream; The distance that a boat is carried by the tidal stream in a given time
  • Drogue
    A device to slow a boat down in a storm so that it does not speed excessively down the slope of a wave and crash into the next one. It is generally constructed of heavy flexible material in the shape of a cone. Also see sea anchor.
  • Drying Height
    The height measured from Chart Datum of any point which is sometimes covered. (The green bits on the chart between CD and MHWS.)
  • DSC
    Used to send messages like texts using the vessel’s radio. Especially useful for sending Distress calls.
  • DTW
    Distance to travel until your reach your next waypoint.
  • e

  • Ease Out
    To let a rope out gradually
  • Ebb
    The period when the tidal level is falling
  • Echo
    Phonetic alphabet letter E
  • Echo Sounder
    An electronic depth-finding instrument
  • Echo Sounding
    The result of measuring the depth of the water using a sonar device or Echo Sounder
  • Electronic Chart Plotter
    The electronic chart plotter provides a GPS position and other navigational information. Chart plotters should always be used in conjunction with paper navigation charts.
  • Electronic navigational chart
    An electronic navigational chart or ENC is an official database created by a national hydrographic office for use with an Electronic Chart Display and Information System (ECDIS). An electronic chart must conform to standards stated in the International Hydrographic Organization (IHO)(...)
  • Electronic Position Indicating Radio Beacon
    Electronic Position Indicating Radio Beacon that transmits a distinctive signal on a distress frequency
  • ENC
    An electronic navigational chart or ENC is an official database created by a national hydrographic office for use with an Electronic Chart Display and Information System (ECDIS). An electronic chart must conform to standards stated in the International Hydrographic Organization (IHO)(...)
  • Ensign
    The national flag flown at or near the stern of a vessel to indicate her nationality
  • EP
    The assumed position of a vessel based on Dead Reckoning and allowing for wind and tide.
  • EPRIB
    Electronic Position Indicating Radio Beacon that transmits a distinctive signal on a distress frequency
  • Estimated Position
    The assumed position of a vessel based on Dead Reckoning and allowing for wind and tide.
  • Estimated Time of Arrival
    Calculated time of arrival at destination.
  • ETA
    Calculated time of arrival at destination.
  • Even Keel
    A vessel floating so that her mast is more or less vertically upright
  • Eye Splice
    A closed loop or eye at the end a line, rope, cable, etc. It is made by unraveling its end and joining it to itself by intertwining it into the lay of the line. Eye splices are very strong and compact and are employed in moorings and docking lines among other uses.
  • f

  • Fair
    Advantageous or favourable, as of wind or tidal stream; In weather meaning no significant precipitation
  • Fairlead
    A ring, hook or other device used to keep a line or chain running in the correct direction or to prevent it rubbing or fouling.
  • Fairway
    The main channel in a body of water such as an estuary or river
  • Fairway Mark
    Buoy, post or pillar positioned at safe distance to seaward of a channel. See also Safe Water mark.
  • Fender
    Any device hung outboard to absorb the shock when coming alongside and to protect the hull when moored alongside
  • Fetch
    The distance travelled by the wind when crossing open water.  The height of the waves is proportional to the fetch and strength of the wind
  • Fid
    A tapered tool used for separating the strands of rope for splicing.
  • Fix
    The position of a vessel as plotted on the chart from position lines obtained by compass bearings, direction finder, echo sounder etc.
  • Flares
    Flares are pyrotechnics and one of the most effective means of signalling distress and marking your position. There are several types of flare designed for use in different waters
  • Flashing Light
    A light where there is more darkness than light
  • Flood
    The period when the tidal level is rising
  • Fluke
    The wedge-shaped part of an anchor's arms that digs into the bottom.
  • Flying Out
    A sail is flying out in a breeze when it has no tension in the sheets
  • Fo'c'sle
    The part of the accommodation below the foredeck and forward of the mast
  • Fog
    Visibility reduced to less than 1000 metres (approximately 0.5 nautical miles)
  • Foghorn
    Fog horns are used for sounding the appropriate sound signal whilst in restricted visibility
  • Folding Propeller
    A propeller with folding blades, furling to reduce drag on a sailing vessel when not in use
  • Following Sea
    Seas that are moving in the same direction as the vessel is heading
  • Foot
    The foot is the bottom edge of the sail. The foot is attached at either end by the tack and clew. The mainsail foot may also run through a groove set into the boom. If it is not it is known as 'loose-footed main'
  • Fore Triangle
    Area between mast and forestay.
  • Fore-and-aft
    Parallel line between the stem and stern
  • Foredeck
    The part of the deck that is forward of the mast and coachroof
  • Forehatch
    A hatch, usually in the foredeck
  • Forepeak
    The most forward compartment in the bows of the vessel
  • Foresail
    The headsail set on the forestay
  • Forestay
    The stay from high on the mast to the stemhead providing fore-and-aft support for the mast
  • Forward
    Toward the bow of the vessel (pronounced “forrard”)
  • Foul
    The opposite of clear; Adverse (wind or tide); Unsuitable
  • Foul Anchor
    An anchor whose flukes are caught on an obstruction on the seabed or tangled with the cable
  • Foxtrot
    Phonetic alphabet letter F
  • Freeboard
    The vertical distance between the waterline and the top of the deck
  • Full Rudder
    The maximum angle to which the rudder can be turned
  • Furl
    To roll or gather a sail against its mast or spar
  • Furling
    Rolling up or gathering and lashing a lowered sail using sail ties or shock-cord to prevent it blowing out
  • g

  • Gaff Rig
    Gaff rig is a sailing rig (configuration of sails) in which the sail is four-cornered. The sail is controlled at the top usually by a head spar (pole) called the gaff. The gaff enables the sail to be four sided, rather than triangular, and as much as doubles the sail area that can be carried(...)
  • Gale
    In the Beaufort Scale, wind force 8, 34 to 40 knots. Severe gale, force 9 is 41 to 47 knots
  • Galley
    An area where food is prepared and cooked
  • Gelcoat
    The outer unreinforced layer of resin in a GRP hull
  • Genoa
    A large overlapping headsail set in light breezes
  • Give Way
    To alter course in order to concede passage to another vessel
  • Give Way Vessel
    The vessel whose duty it is to keep clear of another, she should take early and substantial action to avoid a collision
  • Glass Reinforced Plastic
    A fibre reinforced polymer made of a plastic matrix reinforced by fine fibres of glass. GRP is a lightweight, extremely strong, and robust material.
  • Global Maritime Distress Safety System
    Is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft.
  • Global Positioning System
    A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver.
  • GMDSS
    Is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft.
  • Go About
    To change tack by altering course to bring the wind on the other side
  • Going Astern
    When going backwards through the water you may hear the skipper say: "I am going astern".
  • Golf
    Phonetic alphabet letter G
  • Goose Winging
    To set the mainsail on one side of the vessel and the headsail on the other when running
  • Gooseneck
    Fitting that attaches the boom to the mast, allowing it to move freely.
  • Goosewinged
    Having one sail set on each side of the boat when running directly downwind.
  • GPS
    A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver.
  • Grab Rail
    Rails fitted above and below decks to grab at when the vessel heels
  • Ground
    A general term for the anchors, cables and all the gear required when anchoring
  • GRP
    A fibre reinforced polymer made of a plastic matrix reinforced by fine fibres of glass. GRP is a lightweight, extremely strong, and robust material.
  • Guard Rail
    Safety line fitted round the vessel to prevent the crew falling overboard
  • Guardrail
    The guardrail is normally made of thin wire and protects the crew from falling overboard. It runs around the full deck supported by stanchions and attached to the Pulpit and Pushpit.
  • Gunwale
    The upper edge of the side of a vessel
  • Guy
    A line attached to the end of a spar to keep it in position
  • Gybe
    To change from one tack to another by turning the stern through the wind
  • Gybe-oh!
    The call to indicate that the helm is being put across to gybe
  • h

  • Halyard
    A line or rope with which a sail, spar or flag is hoisted up a mast
  • Hand Bearing Compass
    Portable magnetic compass with which visual bearings are taken
  • Handrail
    A wooden or metal rail on the coachroof or below deck which can be grabbed to steady a person
  • Handy Billy
    A loose block and tackle with a hook or tail on each end, which can be used wherever it is needed. Usually made up of one single and one double block.
  • Hank
    A fastener attached to the luff of the headsail that attaches the headsail to the forestay. Typical designs include a bronze or plastic hook with a spring-operated gate, or a strip of cloth webbing with a snap fastener
  • Harden In
    To haul in the sheets to bring the sail closer to the centreline; the opposite of ease out
  • Harden Up
    Turn towards the wind; sail closer to the wind.
  • HAT
    The highest level the tide will reach based on the luna cycle
  • Hatch
    A covered opening in a ship's deck through which cargo can be loaded or access made to a lower deck; the cover to the opening is called a hatch cover
  • Haul In
    To pull in, usually a sheet, halyard or anchor line
  • Head
    The bow or forward part of the vessel; The topmost part of the sail attached to the halyard which is pulled to raise the sail up the mast or forestay
  • Head to Wind
    To point the stem of the vessel into the wind
  • Heading
    The direction in which the vessel’s head is pointing
  • Headland
    A fairly high and steep part of the land that projects into the sea
  • Heads
    The lavatory on a vessel
  • Headsail
    Any sail set forward of the mast or of the foremast if there is more than one mast
  • Headway
    Movement through the water stem first    
  • Heave To
    Stopping a sailing vessel by lashing the helm in opposition to the sails. The vessel will gradually drift to leeward, the speed of the drift depending on the vessel's design.
  • Heel
    The angle a vessel leans over in the wind.
  • Height of Light
    The height of a charted object such as a lighthouse or other feature measured from MHWS.
  • Height of Tide
    The vertical distance at any instant between sea level and chart datum
  • Helm
    A ship's steering mechanism. A person who steers a ship.
  • Helmsman
    The member of the crew who steers the vessel
  • Highest Astronomical Tide
    The highest level the tide will reach based on the luna cycle
  • Hitch
    A knot used to tie a rope or line to a fixed object. Also see bend
  • Hoist
    To raise an object vertically with a halyard
  • Holding Tank
    Storage tank for human waste to avoid fouling inshore waters. Required in most European countries, but not currently UK.
  • Horseshoe lifebuoy
    A horseshoe-shaped lifebuoy should be mounted where it can quickly be thrown to a ‘man’ overboard (MOB). The lifebuoy needs to be ready for action immediately so make sure it's not tied on! Many horseshoe buoys will have a drogue fitted which will fill with water and help prevent drifting, and(...)
  • Hotel
    Phonetic Alphabet H
  • Hounds
    Attachments of stays to masts.
  • House flag
    Any personal flag or club flag flown from starboard spreaders or flagstaff.
  • Hull
    The body of a vessel excluding masts, rigging and rudder
  • Hull Speed
    The maximum efficient speed of a displacement-hulled vessel.
  • Hurricane
    In the Beaufort scale, wind of force 12, 64 knots or above
  • Hydrofoil
    A boat with wing-like foils mounted on struts below the hull, lifting the hull entirely out of the water at speed and allowing water resistance to be greatly reduced.
  • Hydrography
    The science of surveying the waters of the earth and adjacent land area, and publishing the results in charts, pilots, etc, for example Admiralty charts
  • i

  • IALA
    The body which is responsible for he International buoyage system
  • IMO
    A specialised agency of the United Nations responsible for regulating shipping. Headquartered in London, the IMO has 173 Member States and three Associate Members
  • Impeller
    Screw-like device which is rotated by water flowing past: used for measuring boat speed and distance travelled through the water
  • In Irons
    When a sailing vessel has lost its forward momentum while heading into the wind, rendering it unable to steer.
  • In Stays
    When the bow points directly into the wind with the sails flapping during the process of going about
  • India
    Phonetic Alphabet I
  • Inshore
    Near to or towards or in the direction of the shore
  • International Association of Lighthouse Authorities
    The body which is responsible for he International buoyage system
  • International Maritime Organisation
    A specialised agency of the United Nations responsible for regulating shipping. Headquartered in London, the IMO has 173 Member States and three Associate Members
  • International Regulations for Preventing Collisions at Sea
    Published by the International Maritime Organisation (IMO) they set out, among other things, the "rules of the road" or navigation rules to be followed by ships and other vessels at sea to prevent collisions between two or more vessels.
  • IRPCS
    Published by the International Maritime Organisation (IMO) they set out, among other things, the "rules of the road" or navigation rules to be followed by ships and other vessels at sea to prevent collisions between two or more vessels.
  • Isobar
    On a synoptic chart, a line joining points of equal pressure
  • Isolated Danger Mark
    Buoy or pillar positioned on a dangerous underwater obstruction
  • Isophase
    A light where the duration of light and darkness are equal
  • j

  • Jackstay
    A jackstay is a length of webbing (or on rare occasions a length of wire) which run from the bow to the stern of the vessel. They have sufficient slack in them so that you can clip your lifeline to it while still in the safety of the cockpit. You are then able to leave the cockpit safe in the(...)
  • Jammers (see Clutches)
    Jammers or clutches are used to secure lines that have been tensioned on a winch. The jammer or clutch holds the rope should the winch be needed for another line
  • Jib
    Triangular headsail set on a stay forward of the mast
  • Jib Sheets
    Lines attached to clew of headsail to control sail shape.
  • Juliet
    Phonetic Alphabet J
  • Jury Rig
    A temporary but effective device that replaces lost or damaged gear
  • k

  • Kedge
    A technique for moving or turning a ship by using a relatively light anchor known as a kedge.
  • Kedge Anchor
    A lightweight anchor used to move a boat or anchor temporarily in fine weather
  • Keel
    A structural element that sometimes resembles a fin and protrudes below a boat usually along its centre line
  • Ketch
    A two-masted fore-and-aft rigged sailboat with the aft mast (the mizzen) mounted (stepped) afore (in front of) the rudder.
  • Kicking Strap
    Line or tackle to pull the boom down to keep it horizontal
  • Kilo
    Phonetic Alphabet K
  • Knot
    The unit of speed at sea; nautical miles per hour; A series of loops in a line or rope
  • l

  • Landfall
    Land first sighted after a long voyage at sea
  • Lanyard
    A short length of line used to secure an object such as a knife
  • Lash Down
    To secure firmly with a rope or line
  • LAT
    The lowest level the tide will reach based on the luna cycle; used as Chart Datum in many publications
  • Lateral Mark
    Buoy, or post used to mark Port and Starboard sides of a channel
  • Latitude
    Parallels of latitude are parallel equidistant lines running north and south from the zero degree point at the equator. They are graduated at one degree intervals starting at zero degrees at the equator to 90 degrees at the North and South Poles, hence 30 degrees north or 45 degrees south.(...)
  • Lazarette
    Large aft locker or glory hole for storing everything from fenders, to dinghies, fishing kit and everything else you can imagine.
  • Lazy Jacks
    A network of cordage rigged to a point on the mast and to a series of points on either side of the boom that cradles and guides the sail onto the boom when the sail is lowered.
  • Lead Line
    A line marked with knots at regular intervals and attached to a heavy weight; used to determine the depth of water
  • Leading Lights
    Lights positioned to assist entry into harbour or safe passage through a channel. Usually one light above another marks the correct course.
  • Leadline
    An instrument used in navigation to measure water depth; the line attached to a lead.
  • League
    A unit of length, normally equal to three nautical miles.
  • Lee
    The direction towards which the wind blow
  • Lee-oh!
    Command given by helm when tacking as the bow passes through the wind. Tells the crew to reset the sails on the new course.
  • Leech
    The trailing edge of a triangular sail
  • Leeshore
    A coastline towards which the onshore wind blows; the shore to leeward of a boat
  • Leeward
    The opposite direction to windward; downwind, away from the wind
  • Leeway
    Sideways action of wind on the vessel
  • Leg
    A segment of a voyage between two waypoints
  • Length Overall
    Length Overall
  • Lifeline
    Personal safety device attached to harness on lifejacket and to vessel strongpoint. Designed to keep you on board
  • Liferaft
    Emergency flotation device to allow the crew to abandon ship in a gravely dangerous situation
  • Lighthouse
    Major light used to assist safe passage and help vessels avoid obstructions.
  • Lima
    Phonetic Alphabet L
  • Line
    Alternative name for a small rope or for a rope used for mooring a vessel
  • List
    A permanent lean to one side or the other
  • LOA
    Length Overall
  • Lock
    A chamber with gates at each end in which the water level can be raised or lowered
  • Locker
    An enclosed stowage anywhere on board
  • Log
    A device to measure speed and distance through the water usually uncorrected for tidal stream
  • Log Reading
    The reading of distance travelled through the water usually taken every hour from the log and recorded in the deck log
  • Logbook
    A book to keep a record of events, distance run and courses, etc.
  • Longitude
    The vertical lines of longitude are called meridians and run from and to the poles, the zero degree line runs through Greenwich, London. The lines run from zero to 180 degrees East and West of the Greenwich Meridian. Like the parallels of latitude, meridians of longitude are divided into(...)
  • Look-out
    Visual watch; Member of the crew responsible for keeping it
  • Lose Way
    A vessel loses way when she slows down and stops in the water
  • Lowest Astronomical Tide
    The lowest level the tide will reach based on the luna cycle; used as Chart Datum in many publications
  • Lubber Line
    The marker in the compass which is aligned with the fore-and-aft line of the boat against which the course can be read off on the compass card
  • Luff
    The luff is the forward, vertical edge of the sail, which runs up the mast or forestay.
  • Luff Up
    To steer a sailing vessel more towards the direction of the wind
  • Lull
    A temporary drop in wind speed
  • m

  • Magnetic North
    The area of the globe where compasses point, it's a variable location moving each year. See also Variation & True North
  • Mail Sail
    To hoist the sails and get under way
  • Mainsail
    The principal sail
  • Mainsheet Traveller
    The athwartship slider to which the mainsheet tackle is made
  • Make Fast
    To secure the vessel with mooring lines to the jetty or to tie up to a buoy
  • Making Way
    A vessel that is being propelled through the water
  • Marina
    Artificial boat harbour usually consisting of pontoons
  • Maritime and Coastguard Agency
    Agency responsible for the safety of commercial shipping
  • Maritime Mobile Service Identity
    Is a 9 digit unique number that is associated with your specific VHF installation, and really like a digital Call Sign. Think of it as a mobile number for your VHF radio. It enables DSC over the VHF transmission frequencies.
  • Mark
    An object that marks a position
  • Mast
    The most important vertical spar without which no sail can be set
  • Mast Step
    Fitting into which the mast heel fits
  • Masthead Light
    A white light exhibiting near the masthead by a power driven underway
  • MayDay
    Distress call made when vessel or life is in serious and imminent danger. From the French, M’aider.
  • MCA
    Agency responsible for the safety of commercial shipping
  • Mean High Water Neaps
    The average level of all high waters at neaps tides throughout the year;
  • Mean High Water Springs
    The average level of all high waters at spring tides   throughout the year; used as the datum level for heights of features on charts
  • Mean Low Water Neaps
    The average level of all low waters at neap tides throughout the year;
  • Mean Low Water Springs
    The average level of all low waters at spring tides throughout the year;
  • MHWN
    The average level of all high waters at neaps tides throughout the year;
  • MHWS
    The average level of all high waters at spring tides   throughout the year; used as the datum level for heights of features on charts
  • Mike
    Phonetic Alphabet M
  • Mist
    Visibility reduced to between 0.5 and 2 nautical miles due to suspension of water particles in the air
  • Mizzen Mast
    Mast aft of the mainmast, on a ship.
  • MLWN
    The average level of all low waters at neap tides throughout the year;
  • MLWS
    The average level of all low waters at spring tides throughout the year;
  • MMSI
    Is a 9 digit unique number that is associated with your specific VHF installation, and really like a digital Call Sign. Think of it as a mobile number for your VHF radio. It enables DSC over the VHF transmission frequencies.
  • Mole
    A breakwater made of stone or concrete
  • Monohull
    A vessel with a single hull
  • Mooring
    The ground tackle attached to a mooring buoy
  • Mooring Buoy
    A non-navigational buoy to which a vessel can moor
  • Mooring Ring
    A ring on a mooring buoy
  • Motor sailing
    Sailing vessel making way using Sails and Engine. Downward pointing cone should be displayed in the fore triangle in daylight and lights for power at night.
  • n

  • Nautical Almanac
    Official publication giving positions of heavenly bodies and other information to enable a vessel’s position to be established
  • Nautical Mile
    Unit of distance at sea based on the length of one minute of latitude. One nautical mile or approximately 6076 feet or 1852 metres.
  • Navigation Lights
    Lights exhibited by all vessels between sunset and sunrise
  • Navtex
    A compact system which can be installed on your vessel to receive 518 kHz and 490 kHz broadcasts of weather information.
  • Neap Range
    The difference in height between HW and LW on a Mean (average) neap tide.
  • Neap Tide
    Tides where the range is least and the tidal streams run least strongly
  • Near Gale
    Wind of Beaufort force 7, 28 to 33 knots
  • Not Under Command
    Vessel broken down. No steerage, engines defunct etc.
  • Notice to Mariners
    Official notices issued weekly or at other times describing corrections to charts and hydrographic publications
  • November
    Phonetic Alphabet N
  • o

  • Occulting Light
    A rhythmic light in which the duration of light in each period is longer than the total duration of darkness
  • Offshore
    Wind blowing away from the land or “being at sea”
  • Oilskins
    Waterproof clothing worn in foul weather
  • On the Port Bow
    Ahead of a vessel at an angle to the bows, but forward of the beam, to the left
  • On the Port Quarter
    At an angle to the stern of your vessel, but abaft the beam, to the left
  • On the Starboard Bow
    Ahead of a vessel at an angle to the bows, but forward of the beam, to the right
  • On the Starboard Quarter
    At an angle to the stern of your vessel, but abaft the beam, to the right
  • Onshore
    Wind blowing towards the land or “not at sea”.
  • Oscar
    Phonetic Alphabet O
  • Outhaul
    A line with which the mainsail is hauled out along the boom
  • Overfalls
    Turbulent waters where is a sudden change in depth or where two tidal streams meet
  • p

  • Painter
    The line at the bow of a dinghy
  • Pan Pan
    The internationally recognised radio telephone urgency signal which has priority over all calls except Mayday
  • Papa
    Phonetic Alphabet P
  • Parallel Rules
    Navigational instrument used in conjunction with the compass rose on the chart to transfer bearings and courses to plot a vessel’s position
  • Pay Off
    Let the sails fill and sail away on a new tack.
  • Pay Out
    To let out a line or rope gradually
  • Personal Locator Beacon
    A device worn by crew to enable the transmission of their position in the event they go overboard
  • Pile
    A stout timber or metal post driven vertically into the a river or seabed
  • Pilot
    An expert in local waters who assists vessels entering or leaving harbour; An official publication posting details of, for example, local coasts, dangers and harbours
  • Pinch
    To sail too close to the wind so that the sails lose driving power
  • Pitch
    The up and down motion of the bow and stern of a vessel
  • PLB
    A device worn by crew to enable the transmission of their position in the event they go overboard
  • Plot
    To find a vessels position by laying off bearings on a chart
  • Pooped
    Swamped by a high, following sea.
  • Port
    The left hand side of the vessel looking forward
  • Port Beam
    The port (left) side at the widest part of the vessel (beam)
  • Port Bow
    The port (left) side of the vessel close to the bow (front)
  • Port of Registry
    The port listed in a vessel’s registration documents and lettered on her stern
  • Port Quarter
    The back (stern) left (port) side of the vessel
  • Port Tack
    Sailing with the wind on the port side and the sails set on the starboard side
  • Porthole
    An aperture on the hull of a vessel that admits light and, sometimes, air
  • Portland Plotter
    Useful navigation tool for measuring bearings and drawing lines on the chart.
  • Prevailing Wind
    The wind direction that occurs most frequently at a place over a certain period
  • Preventer
    A line rigged from the end of the boom to the bow in heavy weather to prevent an accidental gybe
  • Propeller Walk
    Tendency for a propeller to push the stern sideways. In theory a right hand propeller in reverse will walk the stern to port.
  • Pulpit
    The pulpit is a strong set of rails at the bow. It is joined to the guardwires and provides protection for crew working at the wet end of the vessel.
  • Pushpit
    The pushpit runs around the stern of the vessel. It is very strong and connects to the end of guardrails providing a continuous safety line around the vessel.
  • Pyrotechnic
    Any type of rocket or flare used for signalling
  • q

  • Q Flag
    Yellow flag flown from starboard spreaders or flagstaff when entering a foreign port (or Channel Isles) requesting customs clearance. Don’t remove until formalities completed.
  • Quebec
    Phonetic Alphabet Q
  • r

  • Race
    A strong tidal stream
  • Radar
    Object detection system which uses radio waves to determine the range, direction or speed of vessels and other objects. The radar dish or antenna transmits pulses of radio waves or microwaves which bounce off any objects in their path.
  • Radar Reflector
    A device hoisted or fitted up the mast to enhance the reflection of radar energy
  • Raft
    Two or more vessels tied up alongside each other
  • Range of Tide
    The difference between sea level at high water and sea level at the preceding or following low water
  • Raster chart
    Electronic chart which is a direct copy of a paper chart with limited zooming capability
  • Rate
    The speed of a tidal stream or current given in knots and tenths of a knot
  • Reach
    A vessel is on a reach when she is either close-hauled or running.  It is her fastest point of sail
  • Reaching
    Sailing across the wind: from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching" (about 90°) and "broad reaching" (about 120° to 160°).
  • Ready About
    The helmsman’s shout that he intends to go about shortly
  • Reef
    To reduce the area of sail, particularly the mainsail
  • Reefing Lines
    Reefing lines are used to reduce the size of the mainsail. By reducing the size of the mainsail we can improve the yacht's stability and performance as the wind increases
  • Restricted in Ability to Manoeuvre
    Unable to get out of the way due to work being done. Could be a dredger, towing vessel etc.
  • Restricted Visibility
    Visibility restricted by rain, drizzle, fog, etc., during which vessels are required to proceed at a safe speed and to navigate with extreme caution
  • Rhumb Line
    A line on the surface of the earth that cuts all meridians at the same angle.  On a standard Mercator chart the rhumb line appears as a straight line
  • RIB
    A vessel that has both a solid part and inflatable part to its structure
  • Riding Turn
    On a winch the situation where an earlier turn rides over a later turn and jams
  • Rigging
    All ropes, lines, wires and gear used to support the masts and to control the spars and sails
  • Rigid Inflatable Boat
    A vessel that has both a solid part and inflatable part to its structure
  • Risk of Collision
    A possibility that a collision may occur; usually established by taking a compass bearing of an approaching vessel
  • Roller Furling
    For simplicity the roller furling sail and drum means that the headsail does not need to be hanked on or fed up the groove in the forestay. The sail can be rolled away when not required in a matter of seconds.
  • Roller Reef
    A method of reefing where the sail area is reduced by rolling part of the sail around the boom or into the mast
  • Romeo
    Phonetic Alphabet R
  • Round Up
    To head up into the wind
  • Roving Fender
    A spare fender held ready by a crew member in case of emergencies
  • Rudder
    A control surface in the water at or near the stern, used for altering course
  • Rudder Stock
    The rudder stock houses the mechanism that transfers the movement of the wheel or tiller to the rudder, thereby steering the yacht
  • Run
    To sail with the wind dead astern
  • Running Fix
    A navigational fix when only a single landmark is available.  Two bearings are taken and plotted at different times, making allowance for distance travelled
  • Running Rigging
    All rigging that moves and is not part of the standing rigging
  • s

  • Sacrificial Anode
    A zinc plate fastened to the hull to prevent corrosion of metal fittings on the hull
  • Safe Water Mark
    See Fairway mark.
  • Safety of Lives at Sea
    Regulations requiring all vessels to offer assistance in case of distress amongst many other things.
  • Sail Locker
    Place where sails are stowed
  • Sail Ties
    Lines used to lash a lowered sail to the boom or guardrails to prevent it blowing about
  • Saildrive
    A saildrive is a transmission system from the vessel's inboard engine. It closely resembles an outboard engine but is fixed in place and sticks through the hull of the vessel.
  • Saloon
    The main cabin of a vessel
  • SAR
    Search and Rescue
  • Save our Soles
    International distress signal made by light, sound or radio
  • Scope
    Amount of cable or 'rode' which is let out when anchoring or laying a cable.
  • Scupper
    Drain hole in the toe-rail
  • Sea Anchor
    A device, such as a conical canvas bag open at both ends, streamed from bow to stern to hold a boat bow or stern onto the wind or sea
  • Sea Breeze
    A daytime wind blowing across a coastline from the sea caused by the rising air from land heated by the sun
  • Seacock
    A stop-cock next to the hull to prevent accidental entry of water
  • Sealegs
    The ability to keep one’s feet in spite of the motion of the boat
  • Sear and Rescue
    Search and Rescue
  • Secondary Port
    Smaller harbours without their own tide tables in the Almanac. Corrections are needed in relation to the closest Standard Port to find tide times and heights of tide here.
  • Sector Light
    Occasionally a light may not be visible through 360 degrees, or it may shine different colours depending on where it is viewed from. In this instance the arcs or sectors of visibility and colours will be shown on the chart by dotted lines and a description of the sector such as 'obscured' or(...)
  • Securite
    An internationally recognised safety signal used on the radio telephone preceding an important navigational or meteorological warning
  • Semi-Displacement Vessel
    A semi-displacement hull combines the features of a planing vessel along with a displacement hull. The vessel will rise at the bow as she increases speed but will never fully reach the ‘plane’
  • Send
    Vertical movement of waves or swell against, for example, a harbour wall
  • Set
    To hoist a sail; The direction to which a tidal stream or current flows; to Set Sail
  • Set Sail
    To start out on a voyage
  • Shackle
    A metal link for connecting ropes, wires or chains to sails, anchors, etc. 
  • Shaftdrive
    Many sailing vessels and most motor cruisers will have a shaftdrive transmission system. A shaft runs from the gearbox, through the hull beneath the waterline to the propeller/s.
  • Shape
    A ball, cone or diamond shaped object, normally black, hoisted by day in a vessel to indicate a special state or occupation
  • Sheet
    Rope or line fastened to the clew of a sail or the end of the boom supporting it.  Named after the sail to which it is attached
  • Sheets
    Lines used to control sail shape
  • Shipping Forecast
    Weather forecast broadcast four times each day by the British Broadcasting Corporation (BBC) for the benefit of those at sea
  • Shipping Lane
    A busy track across the sea or ocean
  • Shipshape
    Neat and efficient
  • Shoal
    An area offshore where the water is to shallow that a vessel might run aground. To shoal is to become shallow
  • Shock Cord
    Elastic rubber bands enclosed in a sheath of fibres, very useful for lashing
  • Shorten Sail
    To reduce the amount of sail set either by reefing or changing to make a smaller sail
  • Shroud
    Parts of the standing rigging that supports the mast laterally
  • Side Deck
    The deck alongside the coachroof
  • Sierra
    Phonetic Alphabet S
  • Sill
    A wall which acts as a dam, to keep water in a marina
  • Slab Reef
    A method of reefing a boomed sail where the sail is flaked down on top of the boom
  • Slack Off
    To ease or pay out a line
  • Slack Water
    In tidal waters, the period of time when the tidal stream is non-existent or negligible
  • Slam
    The underpart of the forward part of the hull hitting the water when pitching in heavy seas
  • Slide
    A metal or plastic fitting on the luff or foot of a sail running in a track on the mast or boom
  • Slip
    To let go quickly
  • Slipway
    An inclined ramp leading into the sea
  • Sloop
    A small to mid-sized sailboat larger than a dinghy, with one mast bearing a main sail and head sail.
  • Slot
    Gap between two sails.
  • Snatch
    Jerk caused by too short an anchor cable in a seaway; To take a turn quickly around a cleat, bollard or Samson post
  • Snug Down
    To prepare for heavy weather by securing all loose gear
  • SOG
    The actual speed your vessel is tracking over the seabed
  • SOLAS
    Regulations requiring all vessels to offer assistance in case of distress amongst many other things.
  • Sole
    The floor of a cabin or cockpit
  • Sole boards
    The vessel's floorboards. Can be lifted to gain access to the bilges.
  • SOS
    International distress signal made by light, sound or radio
  • Sou’wester
    A waterproof oilskin hat with a broad brim
  • Sound
    To measure the depth of water
  • Sounding
    The depth of water below chart datum
  • Spar
    General term for all poles used on board such as a mast, boom and yard
  • Speed Made Good
    The speed made good over the ground; that is , the boat speed corrected for tidal stream and leeway
  • Speed Over Ground
    The actual speed your vessel is tracking over the seabed
  • Spill Wind
    To ease the sheets so that the sail is only partly filled by the wind, the rest being spilt
  • Spinnaker
    A large symmetrical or asymmetrical balloon shaped sail used when running or reaching
  • Spinnaker Pole
    A spar which is used to hold the spinnaker out
  • Spinnaker Pols
    A spar which is used to hold the spinnaker out
  • Spit
    A projecting shoal or strip of land connected to the shore
  • Splice
    To join lines (ropes, cables, etc.) by unravelling their ends and intertwining them to form a continuous line. To form an eye or a knot by splicing.
  • Sports Boat
    Sports boats are sailing vessels designed with one thought in mind - speed! There are many different classes (designs) of sports boats that often race in 'one design' classes which mean there are no handicap calculations to take into account. It's all down to the crew to fight out for the(...)
  • Spray Hood
    A folding canvas cover over the entrance to the cabin
  • Spreaders
    A spar on a sailboat used to deflect the shrouds to allow them to better support the mast.
  • Spring Range
    The difference in height between HW and LW on a Mean (average) spring tide.
  • Spring Tide
    The tides at which the range is greatest: the height of high water is greater and that for low water is less than those for neap tides
  • Springs
    Mooring lines fastened to prevent a boat moving forwards or backwards relative to the quay or other boats alongside
  • Squall
    A sudden increase of wind speed often associated with a line of low dark clouds representing an advancing cold front
  • Stanchions
    Metal posts supporting the guardrails
  • Stand by to Gybe
    A warning, given by the helmsman, that he is about to gybe
  • Stand Off
    To head away from shore
  • Stand On
    To maintain course and speed of your vessel because you have right of way
  • Standard Port
    Large Commercial port with tide tables in the Almanac.
  • Standing Rigging
    Wire rope or solid rods that support masts and fixed spars but do not control the sails
  • Starboard
    The right hand side of the vessel looking forward
  • Starboard Beam
    The starboard (right) side at the widest part of the vessel (beam)
  • Starboard Bow
    The starboard (right) side of the vessel close to the bow (front)
  • Starboard Quarter
    The back (stern) right (starboard) side of the vessel
  • Starboard Tack
    Sailing with the wind on the starboard side and the sails set to the port side
  • Stay
    Part of the standing rigging which provides support fore-and-aft
  • Steady
    Instruction given to the helmsman to keep the boat on her present course
  • Steaming
    Alternative name for a masthead light
  • Steering Compass
    The compass permanently mounted adjacent to the helmsman which he uses as a reference to keep the boat on a given course    
  • Stem
    The forward most part of the hull
  • Stern
    The aft-part of the boat
  • Stern Light
    A white light exhibited from the stern
  • Stern line
    Rope used to secure stern of vessel when mooring.
  • Stopper Knot
    A knot tied in the end of a rope, usually to stop it passing through a hole; most commonly a figure-eight knot.
  • Storm
    Wind or Beaufort force 10, 48 to 55 knots:
  • Storm Jib
    Small heavy jib set in strong winds
  • Stove
    The cooker
  • Stow
    Put away in a proper place.  Stowed for sea implies that all gear and loose equipment has also been lashed down
  • Superbuoy
    Very large buoys, generally more than 5 m in diameter, which are distinguished on charts because their unusually large size renders them a potential hazard to navigation even to large vessels. Superbuoys are also referred to as - ODAS [Ocean Data Acquisition System].
  • Swashway
    A narrow channel between shoals
  • Swinging Room
    The area encompassed by the swing that excludes any risk of collision or grounding
  • Synoptic Chart
    A weather chart covering a large area on which is plotted information giving an overall view of the weather at a particular moment
  • t

  • Tack
    The tack is the lower forward corner of the sail. The tack on the mainsail is attached where the boom meets the mast. The tack on the headsail is attached to the deck or furling drum at the bottom of the forestay.
  • Tacking
    The process by which a sailing vessel can go to windward, making a series of zig-zag ‘tacks’ at an angle to the wind
  • Take In
    Lower a sail
  • Take the Helm
    To steer the vessel
  • Tango
    Phonetic Alphabet T
  • Tell Tales
    Lengths of wool or ribbon attached to a sail or shroud to indicate the airflow or apparent wind direction
  • Tender
    See Dinghy
  • Tidal Stream
    The horizontal movement of water cause by the tides
  • Tidal Stream Atlas
    An official publication showing the direction and rate of the tidal streams for a particular area
  • Tide
    The vertical rise and fall of the waters in the oceans in response to the gravitational forces of the sun and moon
  • Tide Tables
    Official annual publication which gives the times and heights of high and low water for standard ports
  • Tiller
    A lever attached to the rudder head by which the helmsman moves the rudder
  • Time to Go
    Estimated time remaining to a waypoint giving an indication of arrival time
  • Time Zone
    Most tide tables are produced in the standard time for the time zone(s) of the nation in which they apply. These times may need to be corrected at the times of year when Daylight Saving Time (DST) is in effect
  • To Luff
    To steer too close to the wind, causing the sails to flap. Often done to reprieve the wind pressure on the sails while they are adjusted
  • Toe Rail
    A low strip of wood or light alloy that runs round the edge of the deck
  • Topping Lift
    A line from the base of the mast passing around a sheave at the top thence to the end of the boom to take the weight of the boom when lowering the sail
  • Topsides
    The part of the vessel which is above the waterline when she is not heeled
  • Traffic Separation Scheme
    In areas of heavy traffic, a system of one-way lanes were special regulations apply to shipping in this area
  • Transit
    Two fixed objects are in transit when they are in line 
  • Transom
    The flat transverse structure across the stern of the hull
  • Traveller
    Siding mechanism to adjust the aft end of the boom.
  • Tri-colour Light
    Masthead light combining red, green and white lights in one unit.
  • Trim
    To adjust the sails by easing or hardening in the sheets to obtain maximum driving force
  • Trim Tabs
    Flaps which can be pushed up or down to adjust the angles of the bow and heel on a motor vessel
  • Trimaran
    A vessel with three hulls
  • True North
    Where lines of latitude on charts point, the North Pole. See also Variation & Magnetic North
  • True Wind
    The wind created by the current weather system without impact of a vessels movement
  • TSS
    In areas of heavy traffic, a system of one-way lanes were special regulations apply to shipping in this area
  • TTG
    Estimated time remaining to a waypoint giving an indication of arrival time
  • TZ
    Most tide tables are produced in the standard time for the time zone(s) of the nation in which they apply. These times may need to be corrected at the times of year when Daylight Saving Time (DST) is in effect
  • u

  • Underway
    Commonly describes any vessel moving through the water ie by tide, but not under propulsion.  Strictly speaking it refers to any vessel not actually anchored or tied up
  • Uniform
    Phonetic Alphabet U
  • v

  • Vang
    Runs from the base of the mast to a point about a third of the way along the boom. A vang or kicker is used to exert downward force on the boom and so control the shape of the mainsail and its leech
  • Vanishing Angle
    The maximum degree of heel after which a vessel becomes unlikely to return to an upright position.
  • Variation
    The difference in position of the True North Pole and the Magnetic North Pole. The True North Pole is where charts are lined up; all the lines of longitude run up to True North. Magnetic North is where compasses point
  • Vector Chart
    Electronic chart consisting of layers giving ability to zoom and have many more functions than a Raster chart but appearance is different to paper charts.
  • Velocity Made Good
    Actual speed you are making towards your intended waypoint. Different to boat speed as it it calculating speed directly as the crow flies
  • Very High Frequency
    Usually taken as meaning the VHF radiotelephone
  • VHF
    Usually taken as meaning the VHF radiotelephone
  • Victor
    Phonetic Alphabet V
  • VMG
    Actual speed you are making towards your intended waypoint. Different to boat speed as it it calculating speed directly as the crow flies
  • w

  • Wake
    Turbulence behind a vessel. Not to be confused with wash
  • Warp
    Heavy lines used for mooring, kedging or towing, and to move a vessel by hauling warps secured to a bollard or buoy
  • Warps
    Ropes or lines used for securing the vessel alongside.
  • Wash
    The waves created by a vessel. Not to be confused with wake.
  • Wash Boards
    Removable planks fitted in the cabin entrance to prevent water getting in
  • Watch
    A period of time during which a part of the crew is on duty.
  • Water Track
    The vessel’s course through the water, derived from the compass course steered and allowing for leeway but not tide. The line representing water track is drawn on the chart with a single arrow head at its centre point pointing in the direction of travel.
  • Waterline length
    The length of the vessel at the point where it sits in the water. It excludes the total length of the boat, such as features that are out of the water, like a bowsprit. Most boats rise outwards at the bow and stern, so a boat may be quite a bit longer than its waterline length.
  • Way
    Speed, progress, or momentum, or more technically, the point at which there is sufficient water flow past a vessels rudder for it to be able to steer the vessel.
  • Waypoint
    The physical plot on the chart or entered into the GPS unit.
  • Weather Helm
    The tendency of the vessel to turn her bow to windward making it necessary to turn the rudder to maintain a straight heading
  • Weigh Anchor
    To heave up (an anchor) preparatory to sailing.
  • WGS084
    Standard in Satellite derived positions. Charts will indicate if they are calibrated to WGS084 or another system
  • Wheel
    The wheel is used to steer the vessel. This yacht has two wheels so that the helmsman or woman has a clear view up either side of the vessel.
  • Whipping
    Twine bound round the ends of a rope to keep it from fraying
  • Whisker
    Light spar to hold out the clew of a headsail when running, particularly when goosewinged
  • Whiskey
    Phonetic Alphabet W
  • White Horses
    Breaking waves with foamy crest. Not surf breaking on the shore
  • Winch
    A fitting designed to assist the crew hauling on a rope or line
  • Winch Handle
    A removable handle used for operating a winch
  • Windage
    Wind resistance of the boat. Large motor vess3els with high topsides slide sideways easily due to their windage.
  • Windlass
    The winch used for lifting the anchor
  • Windward
    The direction from which the wind is coming
  • World Geodetic System 084
    Standard in Satellite derived positions. Charts will indicate if they are calibrated to WGS084 or another system
  • WPT
    The physical plot on the chart or entered into the GPS unit.
  • x

  • X-ray
    Phonetic Alphabet X
  • XTE
    The distance your vessel is off your intended course.
  • y

  • Yacht
    A recreational boat or ship; the term includes sailing yachts, motor yachts, and steam yachts.
  • Yankee
    Phonetic alphabet letter Y
  • Yard
    A long spar on which a square sail is set
  • Yawl
    A fore-and-aft rigged sailing vessel with two masts, main and mizzen, the mizzen stepped abaft the rudder post.
  • z

  • Zulu
    Phonetic alphabet letter Z