How to Make an Easy Canal Lock

Modern canals use concrete locks.

Humans have used canal locks since early Roman times in order to control waterways so that ships can travel further inland to deliver goods. You can build the simplest form of canal lock, called a flash lock, in order to raise and lower the water level in your canal. A flash canal can consist of a gate and two brackets to hold the gate in place or a gate with posts wedged against the gate for support.

Things You'll Need

• Treated lumber
• Shovel or earth mover
• Screws or nails
• Tar

Instructions

1. Dig out two edges of your canal to hold your canal lock channel using a shovel or earth mover. The size of the holes should be larger in length than the canal and as tall as you intend the water to reach. Each dug side should measure at least one-third of the length of the canal gate in order to prevent the channels from falling out of place due to erosion.

2. Attach three pieces of treated lumber together in an L-shape with nails or screws to create a wooden channel that will hold the canal gate. Repeat the process to create a second channel. Place a channel into each side of the dug out edges of the canal. Pack the dirt around the outside of each channel in order to prevent the channels from moving.

3. Attach each plank of the canal lock to a support frame to construct a gate using treated lumber, similar in appearance to residential fences. Make sure to nail or screw each plank tightly against the other to prevent large gaps between the planks.

4. Fill any small cracks left between the planks with tar in order to prevent leaks. Make sure to get every last crack, because a small crack can create a pressure point that will cause your canal lock to fail.

5. Place the canal gate in the channel locks when the tar fully dries. You may want to wedge large posts at an angle between the ground and outside of the canal lock gate for extra support.

Tips & Warnings

• Water will quickly build up in your canal due to existing water flow and rain. To open the canal lock, you will need another person to help you lift the gate out of the channels.

• Never use untreated lumber to construct your canal lock as the wood will quickly rot, potentially resulting in the flooding of the land directly below the lock.

• For canals with a large width and depth, you should use thicker lumber to construct your lock, because water pressure bearing down on the lock can cause the wood to snap.

References

• History World: History of Canals