Glossary
A
Aback
A boat is taken aback when the wind hits the leeward side. It may drift backwards or stop
Abeam
At right angles to the fore and aft of the vessel
About
Change tack or turn.
Adrift
When a boat is loose or broken away from its moorings or towline
Aft
Towards the rear of a boat
Aground
The boat's hull hits or is lodged on the bottom
Ahead
Forwards
Aids to Navigation
Man-made markers showing safe and unsafe areas
All Standing
All sails are flying when running before the wind
Aloft
Up high, in the sails or rigging
Amidships
The centre of a boat
Anchor
The metal hook used to hold a boat to the sea bed
Anchor Warp
The anchor rope
Anti-Cyclone
A slow-moving high weather system
Astern
Behind the boat
Avast
Stop that
B
Backstay
Part of the rigging supporting the mast, leading to the stern of the boat
Bailer
A container to bail out water from a boat
Ballast
Weight used to improve the stability of a craft
Beam
The widest part of a boat's hull
Beat
Sail closer to the wind
Bilge
An area at the bottom of a boat where water collects to be pumped out at a later time
Bollard
A strong point used to secure a rope
Boom
A wooden or metal spar at right angles to the mast to support the foot of a sail
Bow
A boat's front
Bulkhead
Upright partition that runs across the boat
Buoy
A floating marker anchored to the sea bed
Burgee
A flag usually at the mast head often used to show the wind direction
C
Catamaran
Craft with a twin hull
Centreboard
A board on a pivot that can be tilted downwards to aid steering
Cleat
A device for tying up ropes
Clevis Pin
A small cylindrical pin used in rigging
Clew
The forward corner of a triangular sail
Close Hauled
Sailing as close as possible to the wind
Cockpit
The rear area of the boat
D
Daggerboard
Lifting keel that moves up and down through its case or trunk
Depth sounder
Electronic sonar device to measure water depth
Displacement
Weight of water a craft displaces when afloat
Downwind
When a craft moves in the same direction as the wind
Draught
The depth of a vessel below the waterline, from the surface of the water to the lowest point of the hull
E
Ease
Let out
Ebb
Stream caused by the dropping or falling of the tide
Ensign
A flag carried by a vessel to show its nationality
F
Fair Wind
Following wind
Fathom
Nautical depth measurement equivalent to six feet
Fender
A cushion between boats or in the lock or moorings to prevent damage
Foot
The bottom edge of the sail which is attached to the boom
Fore/Forward
Towards or near the front of the boat
Foresail
The sail immediately in front of the main mast. It is attached to the forestay
Forestay
A cable that runs from the bow to the top of the mast to provide support
Furl
Rolling up a sail
G
Gaff
A spar in a gaff rig (four sided sails)
Go About
A change in tack
GPS
A satellite-based navigation system to tell you your location
GRP
Glass re-inforced plastic used for vessel hulls the hard part of most RIB hulls
Gunwhale
Top side of a boat
Gybe
Change course when sailing downwind to make the sail swing across to the other side
H
Halyard
A rope used to hoist a sail up the mast
Head
The top corner of a sail
Head Up
Turn the boat more towards the direction of the wind
Heads
Toilet on the boat
Headsail
A sail attached to the forestay ahead of the mast
Heeling
When a sailing boat leans away from the wind
Helm
The tiller used to steer a boat
HIN
Unique number stamped onto a boat's hull for identification
Hull
The main body of a boat, usually made from GRP
I
Inboard engine
Internal combustion engine based in the boat
Incidence
The angle between the apparent wind and the sail
K
Keel
The timber at the bottom of the hull that keeps the hull stable
Ketch
A boat with two masts
Kick-Up
A rudder or centreboard that can "kick-up" when it hits something solid
Kicking strap
A device that holds the boom down while still allowing it to move freely from side to side
Kill switch
A switch to shut off the engine
Knot
A nautical unit of speed. One unit = 2000 yards per hour
L
Lanyard
The lashing on the end of a shroud
Lash
Using a light rope to tie something
Latitude
The north-south distance of the equator expressed in degrees and minutes, displayed on charts or GPS
Lee
The side of the vessel away from the wind
Leeward
The direction which the wind is blowing to
Lifelines
Line or wire that attaches a safety harness to a fitting
Lines
Ropes used to control sails or keep equipment safe
LOA
Length overall, the distance between the longest parts of the boat
Log
A record of the course and events on board
Longitude
Geographic distance east or west of the meridian in Greenwich expressed in degrees and minutes, displayed on charts or GPS
Luff
The leading edge of a sail
M
Mainmast
The biggest mast on a vessel
Mainsail
The lowest sail on the mainmast
Mainsheet
Line used to let out or pull in the mainsail
Mast
A vertical pole at right angles to the deck holding up sails and their rigging
Masthead
The top end of a mast
Mayday
An international distress signal that is repeated three times
Midship
Centre of the craft
N
Nautical Almanac
Book published annually containing current navigational, tidal, astronomical data
Nautical Mile
One minute of latitude, equivalent to 1,852m (6,076 ft)
Navigation Lights
Boat lights which help fellow mariners see what a craft is doing. A red light on the port bow, a green light on the starboard bow and a white light at its stern.
Neap Tide
A tide with the smallest rise and fall
O
Offshore Wind
Wind blowing away from land
Onshore Wind
Wind blowing towards land
Outboard engine
Engine mounted on the transom, outside the boat
P
Painter
A line used for towing or mooring which runs from the bow of a boat
Pay Off
Allow the boat to turn to leeward
Port
The left side of a boat when facing front
Port Tack
Sailing a course so the wind comes over the port bow
R
Radar
High frequency radio waves detect objects and show their positions on an electric screen even when it is dark or foggy
Reach
To sail with the wind coming from the side of the boat
Reef
Reducing the amount of sail in a high wind
RIB
Rigid Inflatable Boat with hard bottom and inflatable sides
Rudder
Underwater movable board that aids steering
Run
To sail with the wind behind the craft
S
Safe course
A pre-determined route to navigate treacherous water
Sculling
Rowing a dinghy with a single oar
Sheets
Ropes or wires used to control and adjust a sail
Shroud
Rigging at the side of a mast
Sloop
Single-masted craft with a mainsail and one sail forward of the mast
Spar
Generic term for all masts, booms and bowsprits
Spinnaker
A lightweight triangular sail, used in front of other sails
Spring Tides
Tides with the greatest difference between low and high water
Starboard
The right side of the boat when facing the front.
Starboard Tack
Sailing with the wind coming over the starboard bow
Stays
Wires supporting the mast
Stepped hull
A high-performance hull to make boats go faster
Stern
The back of a boat
T
Tack
Altering course by turning the boat's bow across the wind to make the wind strike the sail from the other side to steer the vessel through the wind
Tidal drift
The strength of the tidal drift
Tiller
Special handle connected to the rudder, used to steer the boat
Transom
The flat rear section of the hull where the outboard motor sits
Trim
Adjust the sails
W
Wake
Wash left behind a boat in the water
Warp
Strong rope used to anchor a vessel
Winch
Mechanical device to pull in sheets
Windward
Towards the direction the wind is blowing from
