It’s Fun Fact Friday and today we’re going to take a look at a fantastic piece of technology, the Falkirk Wheel. It’s a huge, rotating boat lift that connects two canals in Scotland separated by more than 100 feet of elevation. Let’s take a look at why it was built, how it works, and most importantly, if you can ride in it.
Falkirk Wheel. “By Sean Mack - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=2677705”
Why was it built?
The wheel connects the Forth & Clyde and Union Canals. The canals were originally connected by a series of 11 locks that took almost a day to travel through, requiring 3,500 tons of water per run. However, the set of locks was removed in 1933, ending the transit of the two waterways. It wasn’t until 61 years later, in 1994, that lifts were considered as a way to provide passage. Instead of simply remaking the lock flight, the decision was made to create a landmark structure. Construction on the Millennium Link project to rejoin the canals started in 1998 and was completed in 2002 at a cost of £84.5 million. It is the only rotating boat lift in the world.
How was it constructed?
The entire wheel was actually built in Derbyshire, before being deconstructed and taken to Falkirk in 35 truckloads. According to Scottish Canals, “1,200 tonnes of steel was used to create The Wheel and over 1,000 construction staff helped to build it.” It’s held together with more than 15,000 bolts that were tightened by hand! “Twenty metres (66 ft) of loosely packed backfill from the mining operations containing large sandstone boulders was not considered adequately solid foundation for the size of the structure, so deep foundations with thirty 22 m (72 ft) concrete piles socketed onto the bedrock were used.” (from Wikipedia) The aqueduct was thought to be unbuildable, but with the use of 40mm rebar the design was made by ARUP, a British professional services firm.
Boats entering the Falkirk Wheel. “By Pjt56... - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=61815416”
How does the Falkirk Wheel work?
The wheel itself is 35 meters tall and raises boats by 24 meters. Since the Union Canal is 11 meters higher than the wheel, there are two locks that boats must pass through after the trip on the wheel. Each caisson or gondola holds 500 tons of water. Thanks to Archimedes’ Principle, an object in water displaces the same weight of water. This means that no matter how many boats, people, or even the size of the boats in the wheel, it is always balanced. To raise 500 tons of water 24 meters would require at least 32 kilowatt hours (kWh) of power. Since the wheel is balanced, the mechanism only needs to get moving and slow down to stop. With the weight only being rotated, rather than lifted, the power required for the Falkirk Wheel is only 1.5 kWh per half-turn of the wheel. Put another way, this structure uses the power needed to boil 8 kettles of water to move 1000 tons of water and boats. The caissons are 6.5 meters wide and can hold four 20 meter long canal boats at once.
Once the boats are in, vertically hinged doors create a watertight seal. Securing pins and hydraulic clamps hold the wheel in place until it is ready to move. To minimize directional wear, the lift rotates in both directions at the discretion of the operator. 10 hydraulic motors provide power through a 100:1 gear reduction, making for a 4 minute trip. A gear system ensures that as the wheel rotates, the caissons stay perfectly level.
Cogs that keep the boats level as they are raised. “By Lowattboy at English Wikipedia - Transferred from en.wikipedia to Commons., Public Domain, https://commons.wikimedia.org/w/index.php?curid=2840054”
Check out this short video from Tom Scott about how the wheel works:
It was funded by the Lotteries Act of 1993 that allowed the Millennium Commission to fund projects for good causes. They were required to fund only half the cost of each project, and by 1996 they had enough funds to partially fund the reconnection of the canals.
The design process included many ideas, including a ferris-wheel type design with four gondolas. Inspiration for the design is said to have come from a Celtic double headed spear, a ship propeller, the spine of a fish, and the ribcage of a whale. Tony Kettle, from British Waterways led the design team of 20 people who finalized the concept over a three week period in 1999. The diagram and design of the wheel were actually modelled using Legos from his daughter’s Lego set. Construction of the wheel was completed by more than 1000 workers and is designed to last 120 years.
Can I ride in it?
Yes! Boat trips leave about once per hour and cost £13.50 for a 60 minute ride to the Union Canal and back. The wheel is a big tourist destination, with over 5.5 million people visiting the Falkirk Wheel since it opened in 2002. There are even activities such as peddle boats, water zorbing, mini golf, and of course, food. Looks like we’ll be adding the Falkirk Wheel to our travel list!
Happy Friday!
PS - If you visit the Falkirk Wheel, beware of the Kelpie, an aquatic spirit with shape-changing abilities! They are usually in the shape of a horse, but can also take human form, haunting rivers, streams, and lakes.
Kelpies at the Falkirk Wheel. Image from Spooky Scotland.
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