How Locks Work

How did the locks work?

1. The boat approaches the lock at a lower level of the canal. Valves open in the lower gates to let the water out until it reaches the lower, downstream level of the canal, the lower gates are opened and the boat enters the lock.

2. The lower gates are closed. The valves in the upper gates are opened, allowing water to rise.

3. Any cargo are let on and off.

4. The upper gates are then opened and the boat towed out.