Peterborough Lift Lock facts for kids
Front view of the Peterborough Lift Lock
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| Waterway | Trent-Severn Waterway |
|---|---|
| Country | Canada |
| Province | Southern Ontario |
| Maintained by | Parks Canada |
| Operation | Hydraulic |
| First built | 1904 |
| Latest built | 1980s |
| Length | 43 metres (141 ft) |
| Width | 10 metres (33 ft) |
| Fall | 19.8 metres (65 ft 0 in) |
| Coordinates | 44°18′27″N 78°18′03″W / 44.30750°N 78.30083°W |
| Designated: | 1979 |
The Peterborough Lift Lock is a special kind of boat lift located in Peterborough, Ontario, Canada. It is part of the Trent-Severn Waterway and is known as Lock 21.
For many years, this lock held a world record. Its two lifts were the highest hydraulic boat lifts anywhere. They could raise boats an amazing 65 ft (20 m) (about six stories high!). This was a huge achievement back in the early 1900s. Most regular locks at that time only lifted boats about 7 ft (2.1 m).
In the 1980s, a visitor centre was built right next to the lock. Here, you can try out cool interactive games that show what it's like to go through the lift lock. There are also exhibits that tell the story of how this amazing structure was built.
When winter comes, locals and visitors love to skate on the canal below the lift lock. It's a fun way to enjoy the cold weather!
The Peterborough Lift Lock is very important. It was named a National Historic Site in 1979. Later, in 1987, it was recognized as a Historic Mechanical Engineering Landmark.
There's another similar lift lock on the Trent-Severn Waterway. It's called the Kirkfield Lift Lock and is near Kirkfield. It has the same size basins but lifts boats a bit less high.
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How the Peterborough Lift Lock Works
The Peterborough Lift Lock uses two giant, bathtub-shaped containers called caissons. Boats float into these caissons to go up or down. Each caisson has special gates at its ends. The canal also has gates where it meets the caissons. All these gates open and close together.
Moving Boats with Water Power
Each caisson sits on a large 7.5 ft (2.3 m) wide ram. These rams are like giant pistons that go deep into the ground. They are filled with water and connected by a pipe with a control valve. The caissons slide smoothly up and down on rails attached to tall concrete towers.
The caissons are huge! They are 140 ft (43 m) long, 33 ft (10 m) wide, and 7 ft (2.1 m) deep. When full of water, each one weighs about 1,700 short tons (1,500 t).
What's really cool is that the lift lock doesn't need outside power to work! It uses only gravity and a clever idea called the counterweight principle. Think of it like a seesaw. One caisson always goes up while the other goes down.
Here's how it happens:
- When a caisson reaches the top, it stops about 12 inches (30 cm) below the water level of the upper canal.
- Sensors help make sure the levels are just right.
- The gates open, and water flows into the top caisson until the water levels are equal.
- This extra foot of water adds about 144 short tons (131 t) of weight. So, the top caisson now weighs more (about 1,844 short tons (1,673 t)).
- Boats that just came up exit into the upper canal. New boats wanting to go through enter either the top or bottom caisson.
- Once boats are safe inside, all gates close.
- The valve connecting the two rams opens. Because the top caisson is now heavier, its ram pushes down. This forces water from its shaft into the shaft of the bottom caisson.
- This pushes the bottom caisson's ram up, lifting that caisson to the top!
- When the caisson reaches the bottom, its gates open. The extra water flows out, and boats exit into the lower canal. Then the cycle can start all over again!
In September 2019, the right lift lock was closed for a while after an inspection. Only the left caisson was working. It took longer to go up (using an outside pump) and much longer to go down. Access was limited during this time.
Building the Lift Lock: A Look Back
The Peterborough Lift Lock was designed by a clever engineer named Richard Birdsall Rogers. He was in charge of the Trent Canal. To get ideas, he traveled to countries like France, Belgium, and England in 1896 to see other boat lifts.
A Project with Political Twists
Part of the reason the lift lock was built so quickly had to do with politics. A federal election was happening, and the government wanted to start the project fast to gain local support. So, construction was approved, and contractors were hired even before all the detailed drawings were ready!
The government ended up losing the election. Richard Rogers was worried because he had worked closely with the old government. To keep his job, he released the building plans bit by bit. This worked, and he stayed on as the main designer.
Engineering Firsts
This project included many amazing engineering achievements. It was the first lock ever built using concrete. At the time, it was also the largest structure in the world made with concrete that didn't have steel bars inside to strengthen it.
The construction work was done by two companies: Corry and Laverdure of Peterborough handled the digging and built the concrete towers and lock. The Dominion Bridge Company of Montreal did all the metal work, including the rams, presses, and the huge caissons.
The Peterborough Lift Lock was finished in 1904. It officially opened to thousands of people on July 9, 1904. It's still fully working and used by boats today!
