Narrow Boat Terms

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)

Anode

Large pieces of metal that are welded to the hull. They “take the hit” leaving the hull protected.

Base Plates

The horizontal steel plates that make up the bottom of a canal boat.

Beam

Width of a boat.

Bilge

The lowest inner part of a ship’s hull. Bilge Water collects in the bilge.

Bilge Pump

Pump used to empty the bilge

Bow

The fore-end, or front of a boat.

Bow Thruster

This is a steering aid to assist in maneuvering the boat.

Bulkhead

A wall within the hull of a boat, they provide support and usually separate different sections to reduce the risk of flooding.

Butty Boat

A steel narrow boat with no engine

Calorifier

The hot water tank (like the emersion tank found in houses)

Chine

The horizontal edge where 2 steel sheets meet. If a boat is moulded and round shaped it has no chines.

Counter

Flat area below the water line above the swim.

Draft

The amount of the hull that is below water.

Freeboard

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

Galley

The kitchen on a boat

Galvanic Isolator

A fitting to a boat’s electrical system, intended to help prevent galvanic corrosion to the hull.

GRP

Glass Reinforced Plastic (Fibreglass)

Gunwale or gun·nel

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

Hatch

A trapdoor or cover.

Holding Tank

A tank for holding toilet waste (also called a black water tank)

Hull

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

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.

Port / Portside

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

Pump Out

Means of emptying the holding tank

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.

Rudder

The part of the steering system that is in the water.

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.

Starboard / Starboard Side

Right-hand side when standing at the stern facing forward (towards the frontend)

Stern

The back

Sterngear

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.

Swans Neck

The S shaped steel bar welded to the rudder post to which the tiller bar is fitted (the brass shinny 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 shinny 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.

Tumblehome

The amount a cabin side slops inwards (to give more bridge clearance).

Water Line or wa·ter·line

The line on the boats hull were it floats.

Weedhatch

A weedhatch is a device used to gain access to the propeller and shaft

Windlass

A cranked handle for opening and closing lock paddles.