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Understanding Canal Locks: How They Work

A canal lock is a vital part of river and canal waterways, used for raising and lowering boats between stretches of water at different levels. This article explains the workings of a canal lock, focusing on the process for a boat moving from a lower water level to a higher one.

Canal Lock Structure

The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a caisson) that rises and falls.

How a Canal Lock Works

Here’s a step-by-step explanation of how a canal lock works:

  1. Entering the Lock: When a boat approaches the lock, it enters from either the higher or lower water level. Let’s say the boat is entering from the lower level.

  2. Closing the Entrance Gate: The entrance gate is closed behind the boat, and the boat is now inside the lock chamber.

  3. Opening the Sluices: The lock-keeper opens sluices (small doors) in the other gate (the one leading to the higher water level). This allows water to flow into the lock chamber from the higher level.

  4. Rising Water Level: As the water level inside the lock chamber rises, the boat is lifted up. This continues until the water level inside the lock chamber is the same as the higher water level outside.

  5. Exiting the Lock: Once the water levels are equal, the other gate can be opened. The boat can now move out of the lock, and continue its journey at the higher water level.

The process is reversed when a boat needs to move from a higher water level to a lower one.

FAQ

  1. What is a canal lock?

    A canal lock is a device used for raising and lowering boats between stretches of water of different levels on river and canal waterways.

  2. How does a canal lock work?

    A canal lock works by allowing a boat to enter a chamber, adjusting the water level in the chamber to match the next stretch of water, and then allowing the boat to continue its journey.

  3. What is the difference between a lock and a caisson lock?

    The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; in a caisson lock, it is the chamber itself (usually then called a caisson) that rises and falls.