What a Lock Actually Does

A canal lock is simply a water-filled lift. It moves your boat between two stretches of water sitting at different heights, and it does so using nothing more complicated than gates, paddles and gravity. The gate at one end is closed and sealed, the gate at the other is open to whichever level you're currently sitting in, and the paddles are the little sluices that let water in or out. Get the sequence right and the whole thing becomes a slow, satisfying ritual. Get it wrong and you'll spend twenty minutes wondering why nothing is happening.

On most narrow canals, the chambers are roughly twenty metres long, so a seventy-foot narrowboat slots in with little room to spare. Wider waterways have broader chambers and sometimes mechanical paddle gear. Either way, the principle is identical: you are controlling the movement of water, not fighting it.

Before You Touch Anything

Moor up properly on the lock landing, well clear of the gates and the bywash weir that rushes along beside the approach. Send one person ahead on foot to set the lock, while the helm waits with the boat. A lock landing that looks tidy from a distance can hide a slippery edge, so wear shoes with grip rather than the flip-flops you were wearing on the back deck.

As you walk up, take in three things at once:

• Which way is the water at — is the chamber full or empty, and which gate is the boat going to enter through?
• Is anyone already using it? Never drain a lock someone else is in, and never fill one with a boat inside.
• Do the paddles turn easily, and are the gates leaking hard enough to matter?

If a lock is against you, the chamber needs emptying before you go in. Open the bottom paddles — the ones at the far end — and let the water drain away from you. That's the whole trick: you always move water towards the end you want to open.

Working Through With Two or Three People

On a crewed boat, the smoothest routine is one person at the helm and one on the ground, swapping roles at the next lock if you feel like it. The helm brings the boat in slowly, aiming the bow at the centre of the open gate and using tickover only. Wind and passing boats push you about, so approach at an angle into the wind if there is any, and let the boat straighten itself in the chamber rather than over-steering.

Once the boat is in and clear of the gates, close the gate behind you firmly, then raise the paddles at the far end to let water in or release it out — whichever suits your direction. Stay behind the balance beam or the paddle post, keep your hands off the gate as it moves, and never stand on the gate itself. Water coming through a partially raised paddle is powerful, and a sudden rush can shift a boat sharply.

Talk constantly. The person on the ground can see much more than the helm, who is often looking down at the cabin roof and a stone wall.

Ropes, Bollards and the Art of Doing Very Little

The biggest mistake novice crews make is holding on too hard. In a filling lock, the water pushes the boat forward and sideways; in an emptying lock, she drifts back. A single centre line around a bollard, kept loose enough to slip if the boat drops awkwardly, is usually all you need. Do not tie off tight fore and aft — that's how ropes snap or cleats tear out.

Keep one turn around the bollard and hold the tail by hand. That gives you control without a hard lock-off. If the boat starts to swing, a gentle tug on the centre line is enough to bring her back. If a rope does go taut in a hurry, let it run. Losing a rope is annoying; losing a finger is not a fair trade.

Busy Days and Sharing Nicely

On a summer Sunday the locks can queue four or five deep, and the crews that get through quickest are the ones that cooperate. If another boat is heading the same way, share the lock — two narrowboats fit comfortably in most chambers side by side. Fill and empty once for both of you, and let the boat nearer the gate move out first. Share the paddles too: one crew working the near side, the other the far side.

A few habits keep everyone calm:

• Leave the lock as you would wish to find it — gates closed, paddles down. On some waterways the local convention is gates left open, so watch what others do and follow suit.
• Wait on the landing below if the lock is occupied, not in the middle of the channel.
• Give a hand to a single-hander or an older crew if you're waiting anyway; it costs you nothing and saves everyone time.
• Turn off your engine in a queue if you'll be stationary for a while — it's quieter, and the exhaust won't drift into the boat behind.

When you're the boat in front, don't disappear around the corner without a glance back. A wave to say the lock is set for them is the canal equivalent of holding a door open.

Building Confidence Step by Step

Nobody becomes slick at locks in an afternoon. Start on a quiet stretch with a lock that isn't overlooked, practise the sequence until your hands know it, and accept that a banged fender or a rushed entry is normal. Within a few trips you'll notice the panic has gone and been replaced by something closer to rhythm — the clunk of a paddle, the trickle becoming a roar, the gate swinging open onto the next stretch of water. That's the moment locks stop being a threat and start being the best part of the day.