A lock is simply a chamber with gates at either end. By emptying or filling that chamber with water, your boat can move up or down onto a new section of the waterway.
Once you get to grips with them, locks are all part of the fun of a canal holiday – and a most efficient form of exercise!
Most locks have two sets of gates (top and bottom) and a chamber which your boat enters into. Crucially, locks also have openings (or sluice gates) at the top and bottom and it is by opening these that water is allowed into and out of the chamber to raise or lower the water level - and hence the boat. You and your crew will open and close the paddles using a lock handle (or windlass) which you will carry with you on your cruise.
It may help you to visualise the lock as a huge bath with the taps (top sluices) at the higher end and the plug hole (bottom sluices) at the lower. This may remind you not to run the 'taps' when the 'plughole' is open, which would waste water and never allow the lock to fill.
Special safety tips for locks
Take your time – and keep an eye out for problems
Enter and leave slowly so bumps are less likely to cause damage
Always have a competent person on board while the boat's in the lock
Keep your boat well away from the gates and cills
Boats tend to bang about when water flows in and out of a lock – stay alert
When using fenders, make sure they don't get caught up on the lockside or gates
Watch out for slippery surfaces when you're pushing the gates open
Work out some clear signals so that the crew and skipper can communicate quickly – a signal that means 'close all the paddles, for example
Wait for the boat already in the lock to leave before you start opening or closing paddles. Ask first before helping other boaters to complete the lock operation
Watch out for unprotected drops around the lockside, especially when opening gates
You can read more about operating locks in the illustrated Boaters Handbook including working the paddle gear, staircase locks and more safety tips