What Is a Windlass? A Narrowboat Lock Key Guide

If you are new to narrowboating, the word windlass can sound slightly mysterious. In practice, it is one of the simplest and most important tools you will use on the inland waterways.

A windlass is the removable handle used to operate the paddle gear on canal locks. Without it, you cannot usually raise or lower the paddles that let water in or out of a lock chamber. It is small enough to carry in a pocket or bag, but important enough that many boaters keep more than one on board.

This guide explains what a windlass is, how it works, the main types available, and how to use one safely when travelling by narrowboat.

What is a windlass?

A windlass is a cranked metal handle used on canals to turn the spindle on lock paddle gear. The spindle is usually a square metal fitting connected to the mechanism that raises or lowers a paddle. When the paddle opens, water flows through sluices in the lock gate or through ground paddles beside the lock.

On the UK canal network, a windlass is also commonly called a lock key, lock handle, or sometimes a windlass key. Strictly speaking, it is not a key in the same sense as a Yale key, but the name has stuck because it unlocks the practical business of working a lock.

The classic canal windlass has a socket at one end, a cranked shaft, and a handle. You place the socket over the square spindle and turn. This winds the paddle gear up or down, depending on the direction of travel and the design of the mechanism.

Why is a windlass needed on a narrowboat?

Locks allow boats to move between different water levels. To do this, the crew must control the flow of water into and out of the lock chamber. That flow is managed by paddles, which are raised and lowered using winding gear.

Most paddle gear is too heavy or awkward to turn by hand without a lever. A windlass gives you the leverage needed to operate it. The cranked shape also keeps your hands clear of the spindle and lets you make repeated turns with reasonable control.

On a typical lock passage, a windlass may be used to:

• Raise paddles to fill a lock chamber.
• Raise paddles to empty a lock chamber.
• Lower paddles after use.
• Operate gate paddles and ground paddles.
• Work some lift bridges, swing bridges, and water point mechanisms where compatible gear is fitted.

Not every canal structure uses a standard windlass. Some bridges require a British Waterways key, a handcuff key, an anti-vandal key, or a dedicated mechanism. Even so, the windlass remains one of the most essential items in a narrowboat toolkit.

What does a canal windlass look like?

A canal windlass is usually made from steel, aluminium, or another strong metal. It has a socket that fits over the square spindle on the lock gear. Many modern versions have two different socket sizes, one at each end, to suit different paddle spindles found around the network.

The handle is offset from the socket, creating a crank. This gives the user leverage and space to rotate the windlass without scraping their knuckles on the lock mechanism.

Most windlasses are simple and solid. There are no electronics, batteries, or complex moving parts. The important qualities are strength, comfort, fit, and safe handling.

Common types of windlass

Although all canal windlasses do the same basic job, there are several variations. Choosing the right one can make lock working easier and safer.

Single-headed windlass

A single-headed windlass has one socket size. It may be perfectly adequate on a familiar stretch of canal, especially if the paddle gear is consistent. However, it can be limiting if you cruise widely, as spindle sizes can vary from place to place.

Double-headed windlass

A double-headed windlass has two sockets, usually one at each end. This is a popular choice for narrowboaters because it covers more of the canal network. If one end does not fit the spindle, the other often will.

For many boaters, a double-headed windlass is the most practical everyday option.

Long throw windlass

A long throw windlass has a longer handle or crank. It gives more leverage, which can help with stiff paddle gear. The trade-off is that it may feel slower or more cumbersome in tight spaces.

If you have limited hand strength or often encounter heavy mechanisms, a longer windlass can be useful. It should still be used carefully, as extra leverage also means extra force.

Short throw windlass

A short throw windlass is more compact and can be quicker to spin on light, well-maintained gear. It may be easier to carry, but it gives less leverage on stiff paddles.

Some boaters like to carry both a longer and shorter option, using whichever feels best for the lock in front of them.

Aluminium and steel windlasses

Aluminium windlasses are light and easy to carry. Steel windlasses tend to feel more robust and can give a reassuring weight in the hand. Personal preference plays a part, as does grip, balance, and the type of cruising you do.

Whichever material you choose, avoid using a damaged or badly worn windlass. A loose fit can slip off the spindle, which can be dangerous.

How to use a windlass on a canal lock

Using a windlass is straightforward, but it should never be casual. Lock gear can be heavy, and a spinning handle can cause injury. Good habits make all the difference.

Before winding, take a moment to look at the lock. Check where the boat is, which paddles need to be operated, and whether anyone else is using the lock. If you are unsure, slow down and ask. Rushing at locks is rarely helpful.

The basic method is:

• Place the windlass fully onto the spindle before applying pressure.
• Make sure it fits snugly and is not perched on the edge.
• Keep a firm grip on the handle while winding.
• Stand in a balanced position, away from the lock edge where possible.
• Raise paddles gradually, especially when a boat is in the chamber.
• Watch the effect of the water on the boat and adjust if needed.
• Lower paddles in a controlled way before leaving the lock.
• Remove the windlass from the spindle as soon as you have finished.

Some paddle gear has a ratchet and pawl mechanism to stop the paddle dropping. You may need to lift or release the pawl before winding down. Do this carefully and keep control of the windlass at all times.

Never rely on the mechanism to behave perfectly. Old lock gear can be stiff, uneven, or surprisingly lively. Treat every spindle with respect.

Windlass safety tips

A windlass looks harmless, but it can injure hands, wrists, arms, and faces if used carelessly. The most common risk is allowing the handle to spin back under force. This can happen if the paddle drops or if the mechanism kicks back.

Follow these practical safety tips:

• Never let go while the windlass is under load. Keep hold until the paddle is secure.
• Do not leave a windlass on the spindle. It can fall, trip someone, or be caught by moving gear.
• Keep your face and body out of the swing path. If it slips, you do not want to be in line with the handle.
• Use two hands where sensible. This gives better control on stiff paddles.
• Wind slowly at first. Sudden water flow can move a narrowboat sharply inside a lock.
• Do not force badly jammed gear. If something feels wrong, stop and reassess.
• Supervise children closely. Lock gear is not a toy, even when it looks simple.
• Wear suitable footwear. Lock sides can be wet, uneven, and slippery.

If a paddle will not move with steady pressure, do not jump on the windlass or use unsafe force. It may be jammed, damaged, or already under load in an unexpected way. Check the situation, ask for help if needed, and report faulty equipment to the navigation authority.

Choosing your first windlass

If you are hiring a narrowboat, the hire company will normally provide at least one windlass. Check before you set off and make sure you know where it is stored. Many crews prefer to have two available, especially when working broad locks or travelling with more than one crew member.

If you are buying your own, a double-headed windlass is a sensible starting point. Look for one that feels comfortable in your hand and fits securely on standard paddle gear.

Things to consider include:

• Fit: A good fit on the spindle is essential for control.
• Weight: Lighter models are easier to carry, heavier models can feel steadier.
• Leverage: A longer handle helps with stiff gear but may be less convenient.
• Grip: A comfortable handle is useful during lock-heavy routes.
• Visibility: A brightly coloured windlass is easier to spot if put down on grass or stone.

It is also worth carrying a spare. Windlasses are easy to leave behind at locks, and they can end up in the water if dropped. A spare can save a journey from becoming awkward.

What else might you need alongside a windlass?

A windlass is only one part of the lock-working kit. Depending on where you cruise, you may need other small tools or keys.

Useful items can include:

• Handcuff key: Used on some anti-vandal paddle locks, especially in urban areas.
• CRT facilities key: Often used for water points, refuse areas, toilets, and service blocks on Canal & River Trust waterways.
• Mooring pins and hammer: Useful when mooring where rings or bollards are not available.
• Gloves: Helpful for handling ropes, gates, and cold metal gear.
• Waterproof jacket: Lock working continues in the rain, so staying dry helps morale.

Before a trip, check any route notes or navigation guides for special requirements. Some waterways have unusual locks, bridges, or local operating instructions.

Looking after your windlass

A windlass does not need much maintenance, but a little care helps it last longer and remain safe to use.

After wet weather or muddy lock sides, wipe it down before storing it. Check that the sockets are not cracked, rounded, or badly worn. If it starts slipping on spindles that it used to fit well, replace it.

Store your windlass somewhere accessible, but not where it can roll underfoot. On a cruiser stern or traditional stern, loose tools can become trip hazards. Many boaters use a dedicated locker, hook, or small storage area near the stern.

If you paint or mark your windlass, use a colour that stands out. Black metal can disappear quickly against lock beams, shadows, or towpath edges. A bright handle or coloured tape can make it easier to recover before you cruise away.

Common beginner mistakes

Everyone has to learn lock working, and most mistakes are avoidable with patience. When it comes to using a windlass, the biggest beginner errors are usually caused by rushing or not paying attention to the mechanism.

• Using the wrong end: If the socket does not fit properly, try the other end of a double-headed windlass.
• Opening paddles too quickly: This can send water surging into the lock and move the boat suddenly.
• Standing too close to the edge: Give yourself room to move and keep a stable stance.
• Leaving paddles up: Always lower paddles after use unless local instructions say otherwise.
• Putting the windlass down and forgetting it: Make a habit of returning it to the same place each time.

The best approach is calm and methodical. Look, communicate, wind carefully, and keep an eye on the boat. Lock working becomes much easier with practice.

Frequently Asked Questions

Is a windlass the same as a lock key?

On the canals, many people use the terms windlass and lock key to mean the same thing. A windlass is the handle used to operate lock paddle gear. However, some waterways also require separate keys for facilities, anti-vandal locks, or bridges, so it is worth checking the exact meaning in context.

Do I need my own windlass for a hire boat?

Hire boats are normally supplied with a windlass, often more than one. Before leaving the base, check that you have one on board and ask the hire company to demonstrate how to use it. If you plan to boat regularly, buying your own comfortable windlass can still be worthwhile.

What size windlass do I need?

A double-headed windlass is a good choice for most narrowboaters because it offers two socket sizes. This helps when cruising different canals where spindle sizes may vary. If you stay on one local waterway, a single size may be enough, but a double-headed option gives more flexibility.

Can a windlass be dangerous?

Yes, if it is used carelessly. The main danger is a handle spinning back under force, which can injure the user. Always keep a firm grip, stand clear of the swing path, lower paddles under control, and never leave the windlass on the spindle.

Where should I store a windlass on a narrowboat?

Store it somewhere easy to reach when approaching locks, but secure enough that it will not roll around or become a trip hazard. A locker, hook, or dedicated storage point near the stern works well. Many boaters also keep a spare in a separate place.

A small tool that does a big job

So, what is a windlass? It is the cranked handle that lets you operate canal lock paddles, control water levels, and move a narrowboat safely from one level to another. It is simple, sturdy, and absolutely central to life on the cut.

Choose one that fits well, learn to use it with care, and keep it close whenever locks are ahead. With good habits and a little practice, handling a windlass soon becomes a natural part of the narrowboating rhythm.