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How do Canal Locks Work? Brilliantly Simple Engineering

Canal Locks – a system for connecting two bodies of water that have different water levels – have been around for centuries, and continue to be built today. How do canal locks work? Through brilliantly simple engineering that stands the test of time! Let’s take a look.

How do canal locks work? Learn about this brilliant piece of civil engineering in this post!

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Learning About Canal Locks

I was first introduced to Canal Locks as an elementary school student on a field trip on the River Seine (obviously the lock was on one of the canals that lead to the Seine – maybe St. Martin?). Because, those are the types of field trips ordinary French students go on. We also spent a great deal of time learning about architecture in a real French castle. I don’t remember which castle, but I can still tell you about the differences between Doric, Ionic, and Corinthian columns as a result of those outings.

How do Canal Locks Work? Brilliantly Simple Engineering

I confess that I pretty much forgot about canal locks until we traveled along the Caledonian Canal to reach Loch Ness in Scotland last month. We entered a lock, and my childhood excitement over locks instantly returned. Mike’s students probably thought I was nuts, but when you have four kids you already have that status with college students. This is an excellent status to have, because you get to do whatever you want. You can even become absurdly excited over canal locks. The students put up with you because they think your kids are adorable. Hooray for awesome kids (both my kids AND the college students)!

But, seriously, canal locks are awesome. They allow you to connect two bodies of water that have very different water levels in a very simple and efficient way. Without canal locks, we would have to come up with all sorts of creative ways to do this. We DID see one particularly brilliant alternative while we were in Scotland, and I have a post on that coming up as well. Scotland has a lot of water, and so it’s no surprise that they would develop amazing alternatives.

This is How Canal Locks Work

  1. BEFORE the boat enters, the water levels of the two bodies of water must match.
  2. Once the levels match, the gates open.
  3. The gates close behind the boat.
  4. The boat is moored to the side of the gate.
  5. The water inside the gate lock is either filled with water from upstream or drained downstream, depending on which direction the boat is traveling.
  6. Once the water level inside the gate matches the level on the side the boat wishes to enter, the gates open.
  7. The boat travels through the gate. the gates close, ready for the next boat.

Pipes underneath the the gate combined with water pumps take care of the filling and draining.

Traveling through the Victorian Canal Lock on the Caledonian Canal

I took a series of photos of our boat entering the gate lock on our way back into the Caledonian Canal at the end of our Loch Ness cruise in Scotland last month. I turned the photos into a stop-motion animation, so you can see a lock gate work in real life.

Modeling How Canal Locks Work

Since I can’t take you to the Caledonian Canal (wouldn’t that be awesome?), I thought it would be fun to share some videos to show how the canals locks work.

This college student must like canal locks even more than I do. They built an awesome working model!

This computer animation provides a great visualization of what is going on beneath the surface, that we can’t see!

How do canal locks work? This post has all the answers, including different models to explain how they work.

Besides being home to several canal locks, Scotland has a rotating boat lift (elevator) that is incredible!

Have you ever traveled through a canal lock? 

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MaryAnne is a craft loving educator, musician, photographer, and writer who lives in Silicon Valley with her husband Mike and their four children.

7 thoughts on “How do Canal Locks Work? Brilliantly Simple Engineering”

  1. They really are marvelous feats of engineering. I’ve never gotten to see one in real life, but they sure are fascinating.

  2. Natalie PlanetSmartyPants

    I also found canal locks fascinating. I remember traveling Volga River in my youth and passing through giant locks, I still hope to travel through Panama Canal one day :)

  3. Elisa | blissful E

    I feel like I have been through one, but I can’t remember where. I’ve definitely watched boats go through from the shore, which is pretty fun, too!

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