Canal Cruising Guide
Locks are used for moving the boat from one level of the canal to another - i.e. going up and down hills. They consist of a box with gates on each end and a means of letting water in at the top (higher level) and out at the bottom (lower level).
Some Technical Terms
These are the names used on the UK canals. Please refer to the diagram.
A mechanism which opens holes to let water
into or out of the lock. They come in two sorts:
- Gate paddle: A paddle which opens a hole in the lock gate.
- Ground paddle: A paddle which opens a channel in the ground.
- Windlass: A bent piece of metal with a couple of square holes in one end which is used to wind the paddles up (open) and down (shut).
- Cill: The lip at the top end of a lock, under the gate. Avoid getting your boat stuck on it.
- Pound: The stretch of water between two locks.
- Flight: A group of more than one lock. There can be up to 20 or 30 locks in a flight
- Staircase: A flight of locks where one lock leads directly into another with no pound in between.
How It Works
The best way to understand how a lock works is to try it out. Fortunately, you don't need to find a real one and waste 30,000 gallons of water, as there are some simulations on the web.
Here is an explanation of how a lock works. They don't use all the same terms we do (see above) but the idea is the same. That site has a simulation so you can try it out for yourself. They also have a simulation for staircase locks (locks where the exit gate of one is the entrance gate of another), which gives you a whole set of extra possibilities for things going wrong. However, these are rare on the UK canals.
Now you have the general idea, there are some particular things we do, either for safety or because the UK canals are a bit different to other canals.
- All members of a lock party must wear their buoyancy aid.
- If two boats approach a lock at once from opposite directions, the boat for which the water is already at the right level has priority.
- Never open the paddles until you have an OK from the pilot.
- When going up, we only open the top paddles half way for the first 30 seconds or so. Otherwise, there is too much turbulence in the lock.
- Never walk across a gate where either a) the paddles are open, or b) the water is at the same level on both sides (as it might swing open).
- Unless it's an emergency, always wind paddles down, as opposed to just letting them drop. Letting them drop damages them.
- Never leave your windlass attached to a paddle. If the catch slips, it could seriously damage someone as it flies around or off.
- Never get on or off a boat when it's in a lock without the captain's permission.
If you've never done a lock before then they may seem rather complicated, but they're dead easy when you actually work in a lock party.