This list should help you understand some of the terms used when people talk about Narrow boats:
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)
Bow The front
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.
Gunwale 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.
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 or Port side Left-hand side when standing at the stern facing forward (towards the frontend)
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.
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 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
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).
Waterline The line on the boats hull were it floats.
Windlass or lock key A cranked handle for opening and closing lock paddles.