| Term | Definition |
| Eau | Pronounced O, a fenland term for an artificial channel or cut. |
| Elum or Ellum |  | Combined rudder and tiller of a butty boat. |
| Engine hole | Engine-room space on a motorboat. |
| Eye | A fenland term for the aperture through which water enters or leaves a lock or sluice. |
| Fall | Gear for lowering tackle. |
| False Cratch | A triangular wooden construction forming the rearward part of the cratch. |
| False Floors | Removable floors raising the cargo above the bottom of the boat. |
| Family boat | Boat or barge occupied by the skipper and his family. |
| Fan | Propeller. |
| Fellows, Morton & Clayton | A famous canal carrying company which sold its fleet to the British Transport Commission in 1948. |
| Fender | Protective pad or buffer used to protect a boat from damage. Traditionally of rope work, but now rubber and plastic materials are also used. |
| Fest Ropes | A pair of ropes one on each side of a fen lighter, the loose ends being passed round the steering pole to steady it when in use. |
| Finney | Working boater's term for Fenney Stratford on the GU. |
| Five Paddle | A working boaters term for Home Park Mill Lock, No. 70, on the GU main line. |
| Flash Lock | A weir with a single gate to allow navigation. Boats either had to navigate with, or against, the rush of water or to wait for the whole of pounds on either side of the weir to become equal. Also called a Navigation Weir or Staunch. |
| Flash or Flush | (1) A sudden release of water used to assist navigation on rivers. (2) An inland lake, often caused by subsidence due to salt mining. |
| Flat | Mersey flats, and the larger Black flats, were a type of trading vessel operating around Liverpool and the River Weaver. The term 'flat' is also used to describe the shallow punts or rafts used for canal maintenance. |
| Fleet | A Norfolk term for a shallow. |
| Floodbank | Banks constructed some way back from a river's natural banks, designed to limit the effects of flooding. |
| Fly boat | A swiftly moving canal boat carrying priority cargoes. |
| Fore | The front or forward part of a boat. |
| Forebay | The breast wall and upper sill of a lock. |
| Forestay | Rope or wire securing a mast or upright at the front. Connects masthead and stem post. |
| Freeboard | The space on the side of the hull between the top and the water line. |
| Freshet | An increased flow of a river caused by rain. |
| Gaffsail | Sail supported by a spar or gaff in its upper parts. |
| Galley Beam or Lintel | A beam uniting across the top the gate posts of a pair of lock gates of the old types of river lock hung on hooks and rides. The galley beam keeps the gate posts in place, and prevents these unbalanced type of gate from falling inwards. |
| Gang | Five fen lighters, or two Stour (Suffolk) lighters, chained together for navigation. |
| Gang Planks | (1) Removable planks running along the top of a narrowboat, held by stands, and running from the stern cabin to the cratch. (2) Planks used for access between the shore and a boat or ship. |
| Ganzies | Rushall Locks, BCN. |
| Ganzy | The Rushall Canal. |
| Gas Boats | A decked-in narrowboat used for transporting gas liquor or tar in bulk. |
| Gas two | A working boater's term for the Northchurch Locks, Nos. 51 & 52, on the GU main line. |
| Gate Paddle | Paddles or sluices that admit water to a lock via the openings in a lock gate rather than via culverts built into the ground. |
| Gauging | The measurement of a boat's freeboard in order to calculate the tonnage carried. The scale was established by placing known weights into a boat and recording the measurements appropriate to each weight. |
| Girder | A thin rope, running from the top planks to the cross beam, used for lashing down top planks. |
| Gongoozler | An inquisitive bystander often found by locks and other places where boats gather. |
| Greasy Ockers | Fellows, Morton and Clayton boaters. |
| Ground Paddle | Paddles or sluices that admit water via culverts built into the ground rather than via openings in a weir or lock gate. |
| GU and GUCCC | The Grand Union (canal) and the old Grand Union Canal Carrying Company |
| Gudgeon or Tan Pin | A pin at the foot of the heel post of a lock gate on which the gate turns. |
| Guillotine Gate | A vertically rising lock or stop gate. |
| Gunwale | The upper line or edge, along the hull, of a boat or ship. |
| Half Lock | A staunch or watergate. It differs from a flash lock because the single gate is placed below the weir to make a level rather than to release a flash. |
| Haling Way | Also known as the towing path or haling path. Canal or riverside paths used for towing from. |
| Handspike | A length of wood used to operate lock paddles instead of rack and pinion gears. Still used on the Calder & Hebble Navigation. |
| Hatches | (1) Covers over a cargo space or the entry to a cabin. (2) Rear entrance to the stern cabin of a narrowboat. |
| Head | Immediately above the top gates of a lock is the head of the lock. |
| Head Post | Also called a Breast or Mitre Post. The vertical post farthest from the hanging point of a lock gate. |
| Heel Post | The vertical post on which a lock gate hangs and turns. |
| Helum or Elum | Combined rudder and tiller of a butty boat. |
| Hobbler | A man casually employed by working boatmen to assist them through a lock flight. Also and alternative term to lock wheeling. |
| Hold | Cargo space below deck level. |
| Hold Back | Go astern to slow or stop the boat. |
| Hold In | Hold or turn the boat in the direction of the towing path. |
| Hold Out | Hold or turn the boat in the direction away from the towing path. |
| Hollow Quoin | The recess in which the heel post of a lock gate is fitted and turns during opening and closing. |
| Horse boat | (1) Narrowboat drawn by a horse or other animal. (2) A pontoon or ferry to take horses across a river where there are no bridges and the towing path changes sides. |
| Horse Marines | A term used in Yorkshire for the horse haulage contractors that towed the keels on the canals. |
| House Lighter | A fenland term for a lighter with a cabin. |
| Hythe | A quay or wharf. |
| Ice Plates | Metal plates attached to the front and side of a wooden narrowboat at the waterline to protect the hull from ice sheets. |
| Inclined Plane | A device on wheels that lifted boats from one level to another without using locks. |
| Inside and Inside Turn | Inside is the boaters term for the towpath side of the canal thus an inside turn is one where the deep water is on the towpath side. |
| Invert | An inverted brick, or masonry, arch as used at the bottom of a lock or tunnel. |
| Ippey Cut | The Wilts and Berks Canal. |
| Jack Clough | See Paddle. |
| Jam Hole | Kearley and Tonge's jam factory at Southall on the GU. A regular destination for narrowboat cargoes. |
| Jambing Pole | The pole that projected from fen lighters forming a gang, except for the first and second lighters. The first carried no pole, the second the longer steering pole. |
| Jebus | The false bows attached to the first boat in a train of compartment boats. |
| Joey boat | A day boat often used for short trips, sometimes without a stern cabin. |
| Joshers | Boats which belonged to Fellows, Morton & Clayton Ltd. |
| Keb | An iron rake used to retrieve coal and other articles from the canal bed. |
| Keel | A type of boat once in extensive use on the Yorkshire rivers and canals, they measure approximately 58 feet long by 14 feet beam. |
| Keelson | An inner keel, fitting above or in place of the keel. |
| Knobstick | An Anderton Company working narrowboat. |
| Knuckle or Bull Nose | Knuckle is a dockland term for the rounded stonework at the entrance to a lock. Bull Nose is the equivalent Thames term. |
| Lade Hole | A well in the floor (or shutts) of a narrowboat to facilitate pumping out. |
| Land Water | Water in a river that has drained from the land, as distinct from water forced upstream by the wind or tide. |
| Lanteen sail | Triangular sail attached to a long yard or diagonal with a shorter mast. The mast is stepped well forward, frequently having a short boom at the rear. |
| Lash | This experimental system used a host ship containing up to eighty-nine 435 ton lighters for Atlantic crossings. The lighters were lifted in and out of the host ship by means of a travelling overhead crane, operating from bridge to stern. |
| Lasher | A weir. |
| Lateral Canal | One running alongside a river and using it to supply water. |
| Leam | A fenland term for a drainage and navigation channel. |
| Lee boards | Boards fitted to the side of sailing barges and lowered to decrease the leeway made when sailing close to the wind. These boards act as a keel. |
| Leggers | The people engaged in legging a boat through a tunnel. These may have been the boat crew or professional leggers that were stationed at most long tunnels. |
| Legging | The method of propelling boats through tunnels by two people pushing the boat with their feet against the tunnel walls. Widely used with horse drawn boats, as most tunnels had no towpath. |
| Legging Boards | Boards that could be attached to the front of the boat and which projected out to the sides, on which the leggers lay while legging through a tunnel. Most boats would carry two sets, one for wide, and one for narrow tunnels. Also called wings. |
| Lengthman | A person in charge of a particular length of canal. |
| Let Off | A paddle, or other device, to allow water to be drawn from the canal to regulate water levels or to drain a section for maintenance. |
| Level | A level is said to be made when two reaches of water, one on each side of a lock gate or weir, become level. |
| Lift | A working boater's term for a lock staircase. Can also refer to boat lifts e.g. the Anderton Lift. |
| Lighter | A term including a variety of vessels from the Fens, the Thames, the River Stour (Suffolk) and the Bridgewater Canal. |
| Lintel or Galley Beam | A beam uniting across the top the gate posts of a pair of lock gates of the old types of river lock hung on hooks and rides. The lintel keeps the gate posts in place, and prevents these unbalanced type of gate from falling inwards. |
| Lock | A construction for navigating between different water levels on rivers and canals using controlled changes in water levels to float the boat to its new level. See also Flash Lock and Pound Lock. |
| Lock Distance Post | Posts set 15 or 20 yards from the head and tail of a lock. The first boat to pass the post had claim to the lock. |
| Lock Spit | A shallow trench linking slope holes dug as an early stage of canal excavation. |
| Lock, To | To work a vessel through a lock. |
| Lock Wheeler | Someone who goes ahead (originally on a bike) to get locks ready. |
| Long Boat | River Severn term for a narrowboat. |
| Loobey, Looby or Luby |  | A swivelling piece of metal on the top of a boat's mast to hold a towrope, sprung so as to return to a vertical position. |
| Loodel | A vertical extension to a tiller used when steering high loads such as hay or straw. |
