Abeam 

Off the boat, and at right angles to the fore and aft centreline of the boat.

Aft 

On the boat, towards the stern.

Ahead 

Off the boat, and in front of it.

Aids to navigation 

Devices or systems external to a vessel which are provided to help a mariner determine position or course, to warn of dangers or obstructions, or to advise the location of the best or preferred route.

Amidships 

In the middle of a boat, between bow and stern.

Apparent wind 

The combination of true wind and boat wind

Backing 

A wind shifting in a counter clockwise direction (e.g. W to S to E). In the northern hemisphere a backing wind frequently heralds the approach of poor weather.

Backstay 

Wire running from the top of the mast to the stern. Prevents the mast falling forward and controls fore and aft mast bend.

Battens 

Wooden or plastic slats of varying lengths set in pockets with access at the leech of the sail.

Beam 

The widest part of the hull.

Beam reaching 

Sailing directly across the wind, with the apparent wind on the beam.

Bearing away (bearing off) 

Altering course away from the wind.

Beating 

Sailing to windward in a series of tacks, closehauled first on one tack, then the other.

Belayed 

Secured, made fast to.

Bend on ( a sail) 

Attach a sail to mast, boom or stay.

Bifurcation 

junction

Bight 

Loop of line.

Bilge 

The lowest inner part of a vessel's hull.

Bitter end 

The free end of a line (the other end is the standing end).

Boat wind 

The wind created by a boat's forward motion.

Boom 

A horizontal spar or pole attached at one end to the mast, to support the lower edge of a sail.

Boomvang 

Block and tackle leading diagonally from the boom to the base of the mast. It controls the tension of the after edge of the mainsail.

Bow 

The forward part of a boat.

Breastlines 

Mooring lines that run from bow and stern at right angles to the dock, to keep the boat from moving out from the dock.

Broad reaching 

Sailing in any direction between a beam reach and a run.

By the lee 

Sailing downwind with the wind on the leeward side, i.e. the same side of the boat as the mainsail is being carried.

Cabin 

A below deck compartment for living quarters.

Cable 

Distance of 0. 1 nautical mile.

Cardinal aids to navigation 

Aids indicating the location of hazards and of the safest or deepest water by reference to the four cardinal points of the compass. These aids are positioned so that the safest or deepest water is to be found to the named side of the buoy (e.g. to the north of a north cardinal buoy).

Catboat 

A one masted sailing vessel flying no foresail.

Chainplates 

Strong metal fittings attached to the hull externally or internally, to which the shroud turnbuckles are attached.

Chart datum 

Plane of reference, or baseline, for soundings (depths).

Chock 

A metal fitting used as a guide for a mooring line or anchor rode.

Cleats 

Fittings for gripping or securing lines.

Clew 

Lower aft corner of a sail.

Close reaching 

Sailing in any direction between closchauled and a beam reach.

Closchauled (on a beat) 

Sailing as close to the wind as possible, without the sails luffing.

Cockpit 

An open well in the deck from which the boat is steered.

Companionway 

Stairs or ladder aboard a boat, leading from one level to another.

Cringles (grommets) 

Metal rings worked into a sail.

Cunningham 

Line adjusting the tension of the forward edge of the mainsail.

Current 

Horizontal flow of water.

Cutter 

A sailing vessel having one mast and flying two foresails.

Deck 

Horizontal top surface that secures to and encloses the hull.

Degree 

A distance of 60 nautical miles; one 360th of a circle; one degree of latitude.

Deviation 

Compass error caused by the magnetic properties aboard a boat or of items aboard a boat, and/or the boat itself.

Downhaul 

A line connected to the tack of the sail or gooseneck which is used to adjust the luff tension of a sail.

Ease 

Let out; let off (e.g. a sheet).

Fairleads 

Fittings through which lines are led to guide them or to change their directions.

Fathom 

A measure equal to 6 feet.

Fenders 

Bumpers made of soft material which hang over the sides of the hull to protect it when tying alongside a dock or another vessel.

Fetch 

The distance over open water that the wind has blown.

Flaked 

(1) Line piled neatly back and forth so it can run freely (2) Sail folded back and forth, accordion style.

Float 

A floating dock.

Flushpit (Stern pulpit) 

Metal railing enclosing the stern; the area enclosed by the pushpit.

Foot 

The lower edge of a sail.

Forestay 

Wire running from the top of the mast, or near the top of the mast, to the bow. Prevents the mast falling backward and supports the foresail.

Forward 

On the boat, towards the bow.

Genoa 

A large foresail which overlaps the foretriangle formed by mast, deck and forestay

Give - way vessel

Vessel required to keep clear of a stand on vessel.

Gooseneck 

A hinged fitting attaching the boom to the mast

Gust 

A temporary increase in wind speed lasting a few seconds.

Gybing 

Changing tack while sailing downwind by changing the sails from one side of the boat to the other.

Halyards 

Lines of rope or wire and rope for raising and lowering the sails.

Hanks 

Clips on the luff of a foresail by which the foresail is attached to the forestay

Hard over 

All the way over (refers to the tiller, wheel, or rudder).

Harden 

Tighten; put tension on (e.g. a sheet).

Head 

(1) Top corner of a sail. (2) A marine toilet.

Head to wind 

The bow of the boat is pointed directly towards the direction from which the wind is blowing.

Heading up (luffing, luff up) 

Altering course towards the wind.

Heaving to 

A means of minimizing way and motion of the boat at sea by adjusting sails and lashing the tiller to leeward (wheel to windward).

Heeling 

Leaning over (of the boat).

Helm 

(1) Steering mechanism of a vessel. (2) Person steering the boat (also helmsman).

Hull 

The shell or body of a boat.

Hypothermia (exposure) 

A condition resulting from a lowering of the body's core temperature due to heat loss from the body.

In irons 

The boat is head to wind, with no steerage.

jib 

A foresail that is approximately the size of the foretriangle, or less.

jiffy (slab) reefing 

A means of reducing the size of a sail by partially lowering it and securing the lowered part with lines and ties.

Kedging 

Pulling a boat by its anchor.

Keel 

A weighted underwater extension below the hull. The keel has two functions: (1) It acts as a counterweight to keep the boat upright when the wind is pushing against the sail (it balances the force of the wind on the sails). (2) It reduces leeway (side slip) when the boat is sailing.

Ketch 

A two masted sailing vessel with a mainmast and shorter mizzen (aft) mast. The mizzen mast is stepped forward of the rudder post.

Knot 

Rate of speed equal to one nautical mile per hour (e.g. 6 knots is a rate of speed of 6 nautical miles per hour).

Lateral aids to navigation 

Aids indicating the location of hazards and of the safest or deepest water by indicating the side on which they are to be passed.

Lazarette 

A storage compartment at the stem.

Lee helm 

The tendency of a boat to turn to leeward.

Lee shore 

The shore to leeward (downwind) of the vessel.

Leech 

The after edge of a sail.

Leeward (downwind or lee) 

Away from the direction from which the wind is blowing.

Leeway 

The leeward motion of a boat, a side slipping caused by the wind against the hull and rigging.

Lifelines 

Wires running on each side of the boat from pulpit to pushpit above deck level.

Luff 

(1) Forward edge of a sail. (2) A fluttering in the forward edge of a sail. (3) To alter course towards the direction from which the wind is coming.

Luffing 

(1) Fluttering in the forward edge (luff) of a sail. (2) Heading up.

Luff up 

To head up, causing the sails to luff.

Lying ahull 

Drifting with wheel locked to windward or tiller locked to leeward.

Made fast 

Secured.

Making off 

Securing the free end of a line (e.g. a halyard).

Mast 

An upright pole to support the sails.

Masthead fly 

A wind indicator (windvane) at the top of the mast.

Meridians of Longitude 

Imaginary lines circling the earth in a north south direction from pole to pole and converging at the poles.

Mooring lines 

Docklines.

Nautical mile 

The international nautical mile is equal to 1852m. or 6076 ft. is equal to 1 minute of latitude.

Outhaul 

Line adjusting the tension of the lower edge of the mainsail along the boom.

Override 

Wraps that have jammed on a winch.

P- effect (propwalk or transverse thrust)

The tendency of the stern of a boat under power to "walk" to port or starboard.

PFD 

Personal Flotation Device.

Painter 

The bow line of a dinghy

Parallels of Latitude 

Imaginary lines on the earth that are parallel to the equator.

Pintle and gudgeon 

Two fittings working together to form a hinge. The pintle is the fitting with the pin. The pin is inserted into the socket of the gudgeon.

Points of sail 

Directions in which a boat may sail in reference to the apparent wind. See closereaching, closehauled, beam reaching, broad reaching, running.

Port 

When you face forward, the left side of the boat.

Port tack 

Sailing with the wind on the port side (the boom is carried on the starboard side).

Portlights 

Windows; portholes.

Power driven vessel

Any vessel propelled by machinery.

Pulpit - (Bow pulpit)

Metal railing around the bow; the area enclosed by the pulpit.

Range (of the tide) 

Difference in height between high and low water in a tidal cycle.

Reaching 

Sailing across the apparent wind in any direction between closchauled and running.

Reef points 

Small cringles set into reinforced patches on a sail to accommodate reef ties.

Reference current stations 

Main current stations

Reference ports 

Main tidal ports.

Rode 

The chain, cable or rope attached to an anchor. 

Roller furling foresail (roller reefing foresail) 

A foresail that rolls and unrolls on a rotating foil with a drum and controlling furling line at the bottom.

Rudder 

A flat blade mounted near or on the stern, for steering.

Running (on a run) 

Sailing directly to leeward (downwind, away from the direction of the wind).

Running rigging 

The lines that control the sails, halyards, sheets, outhaul, cunningham, boomvang, topping lift. Running rigging may be adjusted while the boat is sailing.

Sailing free 

A boat is sailing free on any point of sail other than closchauled.

Schooner 

A sailing vessel having two or more masts of equal height, or with the taller mast aft.

Scope 

Ratio of length of anchor rode deployed to the vertical distance from the deck to the sea bed.

Sea room 

(1) Sufficient space on the water to perform an intended manoeuver without running into obstructions such as reefs, shallows, and anchored boats. (2) The water between your boat and the nearest obstruction e.g. your lee shore.

Seamanship 

The skills of handling, maintaining and navigating a vessel.

Seaworthy 

A boat that is safe to take to sea.

Self - bailing cockpit

A cockpit with drainage to the outside of the hull.

Shackles 

Metal fittings (usually U shaped) that close with moveable pins. Shackles attach lines to fittings.

Sheave 

Roller or wheel to guide wire or rope.

Sheets 

Lines which pull in or let out the sails.

Shrouds 

Wires running from the mast to the deck to give lateral support to the mast and to control lateral bend. A boat may have several pairs of shrouds.

Slack water 

The time of the turn of the current when there is little or no horizontal flow of water.

Slides 

Fittings attached to a sail by which the sail is attached to the mast or boom.

Sloop 

A sailing vessel having one mast and flying one foresail.

Sole 

Cabin or cockpit floor, e.g. cabinsole.

Soundings 

Depths

Spar 

A mast, boom, pole or stick. May refer to mast or boom of a vessel.

Spinnaker 

A large balloon like sail, often brightly coloured, used when reaching or running.

Spreaders 

Horizontal bars extending from each side of the mast to hold out the shrouds.

Springlines 

Mooring lines running diagonally from the dock to amidships to prevent the boat from moving ahead and astern.

Squall 

A temporary increase in wind speed lasting a few minutes.

Stanchions 

Upright metal supports for the lifelines.

Stand (of the tide) 

A short period during which there is no change in tidal height. This occurs when the tide has risen to either its high level or fallen to its low level.

Standing rigging 

Wires supporting the mast not usually adjusted when the boat is sailing e.g. forestay, backstay, shrouds.

Stand on vessel

Vessel required to maintain her course and speed at the approach of a give way vessel.

Starboard 

When you face forward, the right side of the boat.

Starboard tack 

Sailing with the wind on the starboard side. The boom is carried on the port side.

Steerage 

Ability of a boat to be steered. A boat can be steered only when water is flowing over the rudder.

Stern 

The after part of a boat.

Storm jib 

A small foresail made of heavy cloth which is used in very strong winds.

Tack 

(1) Lower forward corner of a sail. (2) Port or starboard tack. (3) To change from one tack to the other.

Tacking (coming about) 

Changing direction by turning the boat so the bow passes through head to wind.

Tail 

(1) The bitter end of a sheet leading from a winch. (2) To pull on a sheet.

Tang 

A metal fitting, used to attach the upper end of a shroud or stay to the mast.

Telltales 

Short lengths of wool, ribbon or audiotape attached to sails or rigging to indicate (tell tales Of) the wind direction. Telltales on the sails may be called ticklers.

Through - hulls

Entrances and exits for water in the hull.

Ticklers 

Short lengths of wood or ribbon attached to sails to indicate air flow across a sail.

Tide 

Periodic rise and fall of the waters of the oceans.

Tide- rips

Areas of rough water caused when the wind blows in opposition to a strong tidal current.

Tiller 

A handle attached to the top of the rudder to control it.

Toe rail 

Low rail around the edge of the deck.

Two Block 

In running rigging, the condition of bringing the gaff block on the main up to the cheek block at the truck. Also has the meaning of raising or pulling a sail halyard to its max.

Topping lift 

A line leading from the top of the mast to the after end of the boom to support the weight of the boom when the sail is lowered.

Topsides 

Hull above the waterline.

Traffic separation schemes 

Shipping lanes.

Transom 

Flat area across the stern of a boat.

Trim (set) 

Adjustment of a sail so it can work efficiently

True wind 

The wind felt when the boat is not moving.

Turnbuckles 

Long, threaded, adjustable fittings used to tension wires such as shrouds, stays and lifelines.

Upstream 

The direction taken by a vessel when proceeding from seaward towards the headwaters of a river, into a harbour, or with the flood tide.

Veering 

A wind shifting in a clockwise direction (e.g. E to S to W). In the northern hemisphere a veering wind usually indicates improving weather.

Wake 

The disturbance or waves caused by a boat moving through the water.

Waterspout 

A funnel shaped vertical column of water similar to a tornado but generally less violent.

Way 

The motion of a boat e.g. leeway, headway, sternway, etc.

Weather helm 

The tendency of a boat to turn to weather.

Wheel 

A steering wheel to control the rudder.

Winch 

A drum like mechanical device which is rotated with a handle. A Winch assists in hauling in sheets, halyards and other lines.

Wind chill factor 

A measure of the combined cooling effect of wind and temperature. The larger the wind chill factor, the faster the rate of cooling.

Windward (upwind or to weather) 

Towards the direction from which the wind is blowing. May be referred to as "eye of the wind".

Wing and wing 

Running with the mainsail and foresail set on opposite sides of the boat.

Yawl 

A two masted sailing vessel with a mainmast and shorter mizzen (aft) mast. The mizzen mast is stepped aft of the rudder post.