Useful Narrowboat Terms & Glossary


Narrowboat Glossary

The following list should help you understand some of the terms used when people talk about narrow boats. Also read our blogs and watch our YouTube videos which have lots of interesting facts and information.

Aft = The rear of the boat.

Air draft = The height of the boat taken from the waterline to the highest fixed point on the boat. (So you won’t hit a low bridge)

Amid Ships = Central part of a boat

Annode = a sacrificial chine on a narrowboat, which provides protection of the hull from wearing.

Anser Pins = Steel pins attached, immediately before the stern counter to either or both gunwales of motors and butties to which straps from the stern dollies or studs of both boats can be tightly hooked or shackled when breasting-up, not only keeping the sterns together but also acting as springs and stopping the pair from riding forwards and backwards against each other. Tunnel hooks can also be attached here

Anti-cavitation Plate
= A plate fitted flush to the uxter plate to cover the weedhatch opening.

Beam = The width of a vessel at the widest point.

Bed Cupboard = The decorated cupboard in a boatmans cabin with a tall door that drops down to make into a small double bed.

Berth = A bed or sleeping accommodation on a boat.

Bilge = The compartment at the bottom of the boat where water collects and must be pumped out of the vessel.

Bilge Pump = A pump for removing water that has collected in the bilges.

Blacking = The term used for protective coats of bitumen based paints applied to steel hulls to prevent rusting.

Boatmans Cabin = Originally the after cabin on working boats which provided the crews living and bedroom accommodation. Often replicated on modern traditional style boats.

Boat Safety Certificate = An MOT for narrowboats, which is valid for four years.

Bow = The front.

Bow Thruster = A small propeller or water-jet at the bow, used to turn a vessel at slow speed. Often mounted in a tunnel running through the bow.

= An upright wall within the hull of a ship or boat. Particularly a structural wall which is often watertight.

Bulls Eye = A small round porthole fitted in the cabin top, has convex glass for lighting the cabin.

Butty = An unpowered narrowboat towed behind another, often seen in the days of working boats.

BSC Safety Scheme = All boats require a safety inspection every four years by a qualified Boat Safety surveyor, covers all aspects of boat safety.

Calorifier = Hot water tank heated by the running engine, immersion, central heating or connected to 240v shoreline, (can be a combination)

Canal & River Trust Licence
= Boat Licence to use the canals and rivers.

Cant = A raised outer section of a deck normally to the fore and counter decks.

Cassette Toilet = A chemical toilet with a removable storage cassette underneath, can be electrical flushing.

Chine = An angle in the hull. There may be several chines, depending upon the hull design. A narrowboat often has a single chine where the hull wall and bottom plate meet.

Cockpit = Open area usually lower than the side decks used for storage or sitting out.

Counter = Flat area below the water line above the swim.

Counter Plate = The stern section of the hull side plating above the waterline that wraps around the stern and corresponds to the counter swim.

Cratch Board= A triangular board or frame supporting the forward end of cratch covers.

Cratch Cover= A canvas covering over the forward well deck.

Cross Bed = A double bed going across the full width of the boat, the bottom of the bed folds or slides away during the day for gangway access.

Cruiser Stern
= Narrowboat with a back deck of between 4-8 Feet in length, providing ample space on the back for several people to stand and socialise.

= A seating arrangement with storage under and demountable table which converts to a bed.

Draft = The amount of the hull that is below water.

Dolly = A round bollard used for mooring.

Elsan Disposal = A facility for emptying the contents of a cassette toilet holding tank.

Fiddle = A raised lip or rail around the edge of a shelf to prevent items from sliding off.

Foredeck = The higher level deck in the bow of a boat, often over the gas locker in a narrowboat.

Fore well = The lower deck at the front of a boat.

Freeboard = The distance between the waterline and the lowest deck level where water can enter the inside of the boat.

Galley = The kitchen area of a boat.

Galvanic Isolator = A fitting to a boats electrical system intended to prevent corrosion to the hull.

= The top edge of the hull were it joins the cabin side, laterally gun wall but pronounced gunnel as tunnel.

Hull = The main part of the boat that sits in the water and gives a boat its buoyancy.

Holding Tank = An on board storage tank used for toilet waste, emptied at pumpout stations.

Houdini hatch = A skylight fitted to the roof of the cabin which can be opened for ventilation or emergency escape.

= Electronic device for taking power stored in the battery bank and converting 12v DC to 240v AC.

Josher Style Bow = A bow design with a more pointed nose with a slight S shaped sweep, named after Joshua Fellows of Fellows Morton and Clayton carriers fame.

Keel cooled
= A closed system, a slab tank (narrow & baffled) is welded to the inside (normally) of the swim, engine cooling water is then circulated through it. (Does the same job as the radiator on a car). Important Note the engine and cooling system can easily have anti-freeze added to prevent frost damage.

Macerator Toilet
= Pump out toilet where the waste is macerated into slurry.

Monkey Box = A wooden storage box in a boatmans cabin, believed to be called after a make of polish.

Mushroom Vent = A vent in the roof of the boat shaped like a mushroom, which provides ventillation.

Overplate = On a steel vessel. plating fitted on top of the hull plate.

Pigeon Box = A rectangular hole in the deck head covered with a hinged roof used for ventilation.

Pram Canopy = Canopy fitted on folding framework which is easy to put up and down, fitted over a narrowboats counter to protect the steerer from the elements.

Port or Port side = Left-hand side when standing at the stern facing forward (towards the frontend)

Pumpout Toilet = Toilet where the waste is flushed into a holding tank, which is pumped out at a pumpout facility.

Raw water cooled 1. Direct = Canal water is drawn in via a mud box (normally a watertight container large enough to allow the incoming water time to settle) before being pumped around the engine to cool it then returned to the canal. Important Note the engine and every part cooling system must be completely drained during cold weather to prevent frost damage.

Raw water cooled 2. Indirect
= Canal water is drawn in via a mud box (normally a watertight container large enough to allow the incoming water time to settle) before being pumped though a heat exchanger mounted on the engine it is then returned to the canal. The engines own coolant is also pump through the heat exchanger but is kept separate inside the heat exchanger enabling the engine to be protected with anti-freeze. Important Note The raw water side of the heat exchanger and unprotected parts cooling system must be completely drained during cold weather to prevent frost damage.

RCD = Recreational Craft Directive. EEC Mandatory standards for the construction of new boats. The RCD certificate lasts four years, after which boats must have a Boat Safety Certificate. 

Remote Greaser = A metal cylinder fitted close to the stern tube which acts as a reservoir to grease the stern gland.

Reverse layout = An interior layout with the bedroom at the front and the galley and lounge at the rear.

Rubbing Strake = A moulding fitted to the outside of the hull, usually at deck level to protect the topsides.

Rudder nib = On narrowboats, the extension to the rudder above the waterline.

Ruddertstock = The bar, tube or post connecting the rudder vane to the steering mechanism.

Rudderstock tube = A tube in the hull through which the rudderstock passes.

Sacrificial chine = Extension to the bottom plate to provide protection and wear edge for the chine.

Saloon = The living area on a boat.

Scumble = Painted graining make it look like wood.

Scuppers = Holes through hull sides for draining decks & lockers.

Semi-Traditional = Narrowboat style, good compromise between at trad and semi. The looks of a Trad, with the space of a cruiser

Shoreline = A lead from the shore side connected to a 240v electricity supply..

Single Lever Control = A hand lever combining the functions of steering and throttle control.

Skeg = A steel horizontal bar welded to the base plate (normally in channel form) protruding from the stern to carry the lower end of the rudder post and bearing, it also gives some protection to the propeller.

Skin tank = A steel tank welded to the interior face of the hull. The skin tank forms part of the engine cooling system; coolant passes through the tank and is cooled by contact with exterior hull plating.

Soap Holes = Small storage slots in the bulk head of a traditional style boatmans cabin.

Starboard or starboard side = (from the Norse steerboard the oar that was used to steer the boat) right-hand side when standing at the stern facing forward (towards the frontend)

Stern = The back or aft part of the vessel.

Stern gear = The propeller, propeller shaft, sterntube, sterntube bearing, & stuffing box or packing gland (an adjustable gland to help keep water out of the engine space bilge.

Stern gland = Geased packing arrangement that is used to prevent water from entering a vessel at the point where the propeller shaft passes through the hull.

Stern tube = The tube through the hull through which the propeller shaft passes.

Stretching = The boat is lengthened by cutting through and adding a completely new section to make the boat longer.

Superstructure = The structures on a vessel that project above the deck.

Swans neck = The S shaped steel bar welded to the rudder post to which the tiller bar is fitted (the brass shiny stick with a wooden handle on the end) on a motor boat.

Swim = The after (back) underwater part of the hull that goes to a point to allow a cleaner flow of water over the propeller.

Tiller bar (or extension)
= Fits on the swans neck of a motor boat to give extra leverage. (The brass shiny stick with a wooden handle on the end).

Transom = The normally rounded after (back) part of the boat above the water where the steerer stands.

Traditional Style = A style of narrow boat typified by short back deck of 2-3 Feet in length, giving more room inside for living.

Tumblehome = The amount a cabin side slopes inwards (to give more bridge clearance).

Uxter Plate = The steel bottom plate of a narrowboat's stern counter deck, where it projects over the propeller and rudder.

= The line on the boats hull were it floats.

Weedhatch = A hatch with a watertight lid through the counter of a narrowboat providing access to the propeller for cleaning.

Well Deck = the floor of a well or cockpit.

Windlass or lock key = A cranked handle for opening and closing lock paddles