Beginners Guide To Locks

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You will not go very far on any canal or waterway without coming across locks. Locks are needed to raise or lower the level of the canal according to the lie of the land.
Almost all locks have two bottom gates and one or two gates at the top. Locks vary in length and depth from the very large locks on the Aire & Calder Navigation to ones where the drop is a matter of inches. The ones where the drop in level is only a few inches are usually stop locks situated where two canals join head on; these locks were installed so that one canal could not take water from the other; which in times of little rainfall was very important. 
Most locks have gate paddles, and some have ground paddles and some have both. Gate paddles open sluices set into the gate itself, this allows water to flow directly into or out of the lock. Ground paddles are usually found on top gates, they have a sluice that is set into the side of the lock near the top. Water flows from there through an underground culvert and enters the lock chamber below the lowest water level.
Make sure before you go cruising that you have at least two windlasses, you will need these to operate most locks.
More and more locks are being fitted with anti-vandal devices, make sure you have a handcuff key to open these. It is as well to have at least two of these, and two BW yale keys just in case one is lost

Descending a lock

If the lock is empty, you must fill the lock by opening the top paddles (make sure the bottom ones are shut). When the lock is full you can open the top gates and the boat can enter the lock. Close the top paddles and gates, now you can open the bottom paddles to drain the water from the lock. Keep well away from the the cill which the top gates sit on when descending a lock otherwise your boat could get cought on the cill with disasterous consequences. The extent of the cill is usually marked by a white line on the lock wall. When the water in the lock is the same level as the canal you can open the bottom gates and leave the lock, make sure you close all paddles (unless there are instructions on the lock stating otherwise) and unless a boat is coming into the lock, close the gates.

Ascending a lock

The procedure for ascending a lock is more or less the reverse of descending, but extra precautions should be taken. If the water in the lock is not at the same level as the canal, open the paddles on the bottom gate to let the water out, when the water is level open the gate and shut the paddles, move your boat into the lock and open the top gate paddles slowly and just a few inches at a time. When the water is level you can open the top gates and leave the lock.
When ascending a lock you need to position your boat at the back of the lock or if you have enough experience go right to the front of the lock, touching the front gates. Do not stay in the middle, the force of the water will send you forwards into the front gates, this can cause damage to your boat and to the lock gates and could be very dangerous.
If when you are ascending a wide lock  and there is only your boat in the lock then extra precautions must be taken, you must not go to the front of the lock, stay in the middle and use ropes to keep the boat close to the lock wall, never tie the ropes, pass them round a bollard and back down to the boat so that you can take up the slack in the ropes as needed. Only open the paddles on the side you are against to start with, the water entering the lock will then hit the wall opposite and rebound holding your boat against the wall. When the level has risen and there is less turbulance, the other paddles can be opened with care.

Other Locks

If you cruise in certain areas you will find other types of locks, there are staircase locks and others such as The Bratch on the Staffordshire & Worcestershire Canal that have extra chambers to save water, the working of these locks is explained in another article. Locks are an enjoyable feature of the canal system, but they must be treated with respect, a lot of them are many years old and cannot stand up to continual abuse. Take your time, take care, and enjoy.