Shea Marine

Marine Surveyors

Glossary of boating terms

The Glossary of nautical terms below is assist clients when reading surveys in to the meaning of some of the nautical terms used within the text of survey reports.  The list is continually evolving and any suggestions to additions would be welcome. 


Abaft Rear of any particular point on the vessel. E.g. abaft the mast – behind the mast.
AbeamA point that is at right angles to the line of the keel.
AftThe rear of the vessel or face to the rear
AmidshipsMidway between the back and front of a vessel
AthwartAcross or from side to side of a vessel
AwashA point where water constantly washes over it.
BackstayThe standing rigging from the top of a mast to the back of the vessel to resist forward strain on the mast.
BallastWeight placed in the keel of a ship to increase her stability often Iron or lead.
BattensThin pieces of wood or fiberglass set into the leech of the sail to control shape.
BeamA) The wides point of a vessel. B) A timber across the vessel on which the deck is laid.
BecketAn eye for attaching a rope too normally found attached to a block and tackle.
BelayTo make a rope fast to a belaying pin or cleat.
Bight  A) Any part of a rope between its ends (B) A curve (C) a cove on a coastline or channel.
BinnacleThe box which houses the compass and steering wheel.
Bitter endThe last part of a achor cable/rope that is attached to the vessel when the rest is deployed overboard.
BobstayA stay for the bowspirit to prevent it lifting mounted from bowspirit end to vessels stem at the waterline.
BollardHeavy short post to secure ship’s mooring lines to.
Bolt ropeA strong rope sewn round the edge of sails to give strength from tearing and to locate into a groove up a mast .
BoomA spar to stretch out the foot of a main sail.
Boot topA band of paint at the waterline between wind and water line.
Bower anchorMain anchor carried on a vessel.
BowForward section of a vessel.
BowspiritHeavy spar from deck leading forward from stem head, to which headsails are attached.
Bridle A rope attached to both sides of a boat or object to lift it. Lifting tackle or towing tackle.
BroachAn accidentally turn that places the vessel broadside to the wind and sea.
BulkheadsPartitions fore and aft or Athwartships, forming separate compartments.
BulwarksA vessel’s topsides that extend above the deck.
Cable A) 1/10 Nautical mile, B) anchor chain, C) stainless steel wire.
CapstanA vertical cylindrical machine for hoisting the anchor chain/line.
CarvelGiven to the planking for a vessels hull where the planks are laid edge to edge
CatheadA heavy piece of curved timber projecting from the bow of a ship for the purpose of holding anchors.
CaulkingA term to discribe the filling material used to fill the gaps between a vessels side or deck planking seams to prevent leaking.
CavitationThe loss of effective propeller thrust caused by the blades of a propeller sucking air across the blades of the propeller instead of working within water.
Chain platesMetal strips fastened outside or inside the hull to attach standing rigging too.
ChineThe fore and aft line of the hull where the bilge turns up towards the topsides of the hull.
CleatA T shaped device attached to the vessel for making ropes fast to.
ClewThe corner of the sail where the leech meets the foot.
CompositeConstruction method for a vessel built with a variety of materials.
CounterThe overhanging portion of a stern.
CradleThe frame erected round and under a vessel to support her out of the water.
CringleA round metal thimble mounted within a sail to pass ropes through the sail.
CrownA) Where the arms of an anchor meet the shank, B) the knot when the strands of a rope are interlocked to start a backsplice.
CrutchFitting to support boom.
DavitCrane for hoisting, lowering and holding dinghys in position on a larger vessel.
DisplacementTotal weight of vesselalso known as Deadweight.
DeckheadUnderside of a deck. The roof of a vessels cabin.
DownhaulRope or tackle used to haul down sail or spar.
DraftThe depth of water occupied by a vessel when afloat.
DrogueA sea anchor – a cone shaped canvas bag to which the vessel lies in heavy weather to keep the bow pointing into the waves, or towed from the stern to slow the speed when running.
EnsignThe flag, usually carried at the stern, that denotes a vessel’s nationality.
FairleadA fitting for leading a rope over an obstruction to avoid friction.
FathomA measurement of depth. In units of six feet or 1.83m
FenderSoft rubber or other material to prevent chafe between the vessels side and another vessel and quay.
FiddleA wooden lip to a table to keep objects from sliding off the table in rough waether.
FlareA)The outward spread of a vessel’s topsides B)A distress signal
FootThe lower edge of a sail.
Fore and AftA term used to discribe the lengthways of a vessel.
ForwardTowards the bow of a vessel.
FurlGathering in sail and securing to a spar.
GaffThe spar to which the head of a fore and aft sail is attached to.
GalleyThe kitchen of a vessel of any size.
GallowsFrame of wood or metal with rounded top for supporting the boom.
GimbalsSwivels that hold a compass or stove horizontal at all times when a vessel is at sea.
Goose-neckA metal fitting for securing a boom to a mast. Allows for swing from side to sode and lifting.
GPSGlobal Positioning System
GunwaleThe heavy top rail of at the top of a vessels topsides.
GuyA rope or wire used to control a spar or boom. 
HalyardsRopes or tackle used to hoist pennants or sails up the mast.
HanksStrong clip hooks which attach head sails to the mast stays.
Hawse pipeA pipe leading down through the foredeck through which anchor chain is  led to the storage locker below.
HawserA heavy rope used for mooring, kedging, lineing, towing or as a temporary anchor line.
Head boardA triangular board sewn into the top of a sail, to which the halyard is attached.
HeadsA vessels toilets.
Heaving lineLight line, knotted on end to throw ashore when berthing, as a messenger for a larger mooring line.
HeelA vessel list sideways from the upright.
HelmThe steering mechanism of a vessel (Tiller or Wheel)
HolidayAn unpainted or unvarnished spot in a vessel.
HoundsA band around or attacment on the mast where lower stays or spreaders attach to the mast. 
HullStructure of a vessel below deck level.
Jack StayA bar or rope on which anything travels e.g. a rope leading along the deck, to which safety harnesses may be clipped.
Jack staffSmall staff from which the vessels national flag is flown.
JibThe triangular sail set as the forward headsail.
Jury RigAfter losing mast or rudder, makeshift rig to get the vessel to safety.
Kedge AnchorA lightweight anchor for kedging or moving the vessel by pulling up to it.
KeelThe lower structural backbone of a vessels hull, often seperate unit   bolted to the hull in a modern yacht or intergal in older vessels.  
King spokeThe spoke of the steering wheel which is upright when the rudder is centred.
KnotMeasurement of speed and distance. One nautical mile per hour.
Lapstrake Planking when one edge overlaps the other lower plank. (Clinker)
LaunchTo slide or lift a vessel into the water
Leech The rear edge of a fore and aft set sail.
LeewardDirection away from the wind (loo’ard).
LeewayThe sideways drift of a vessel from her course to leeward, due to wind pressure.
Life lineLine stretched fore and aft for crew to hold on to.
ListWhen a vessel heels to one side through having greater a weight on one side when at rest.
LogAn instrument for recording the distance travelled through water.
Lubber lineLine on the inside of a compass bowl indicating the ships heading.
LuffThe forward edge of a sail
Marline spike Pointed steel tool for opening strand of rope when splicing.
Mast head rigWhen the forestay is rigged to the top of a mast.
Messenger LineA thin line used to draw through another larger line through a mast or confined space. 
MidshipsTo put the rudder fore and aft position.
MoorTo attach the vessel to a dock or fixed bouy with lines.
PintleA vertical pin on which the rudder is hung.
PitchingA vessels movement in at sea in a fore and aft direction.
PoopedA term to indicate that a heavy sea has come inboard over the stern.
PortThe left hand side of a ship looking forward.
Ports /PortholeWatertight window in the ships side or superstructure for ventilation and light.
RakeThe inclination of the mast in the fore and aft line from the vertical.
ReefingTo reduce sail area.
Running riggingRopes that move through blocks generally used to control spars and sails.
Samson postA large post on the foredeck used to secure an anchor or tow line too.
ScantlingsThe dimensions of a ship’s timbers.
SheerThe rise of a ship’s deck towards the bow or stern from amidships.
Sheer strakeThe upper line of plating or planking on the hull.
SheetRope attached to lower corner of sail for regulating its tension.
ShroudStanding rigging that supports a mast athwartships.
SkegA fixed vertical fin attached to the hull on the after side of which the rudder is attached.
SoleThe floor of a cabin or cockpit.
SounderAn electrical instrument to measure the depth of water.
SpringA mooring rope to prevent a vessel moving fore and aft when tied up.
Standing riggingStationary rigging that supports a mast.
StarboardThe right hand side of a ship facing forward.
StemThe forward plank or section of the hull from keel to the deck.
Stern postThe aft plank or section of the hull from keel to the transom.
Tabernacle A box like structure mounted on deck to hold the foot of the mast usually opening aft to allow mast to be lowered.
TackleA purchase of ropes and blocks.
Taff-railA rail around stern of vessel.
ThwartsPlanks placed across the boat to form seats.
TillerA lever for turning the rudder.
TransomThe flat stern of a yacht, originally a board to which the after ends of planking was secured to.
TravellerA metal track with a car running athwartships to allow the main sheet to be trimmed on either side.
Tumble homeWhere a vessel’s sides are inclined inwards above the water line.
TurnbuckleA screw fitting for adjusting the tension of shrouds and stays.
VangA block and tackle or strut for steadying a boom in a vertical orientation
Weather helmA boat has weather helm when it has a tendency to turn up into the wind under sail.
WindwardDirection toward the wind.