The Falkirk Wheel is a rotating boat lift that connects the Forth and Clyde Canal with the Union Canal in central Scotland. It was opened by Queen Elizabeth II during her Golden Jubilee in 2002 and was named after the nearby town of Falkirk. It is the only rotating boat lift in the world and one of only two boat lifts in the United Kingdom.
The Falkirk Wheel was built as part of the Millennium Link project to reconnect the canals for the first time since the 1930s. Planners wanted to create a dramatic 21st century landmark.
The Lotteries Act 1993 raised funds that the Millennium Commission used for good causes in the public interest. The commission provided 42 percent of the money needed for the project. The remaining funds came from British Waterways, seven local councils, Scottish Enterprise, the European Regional Development Fund, and private donations.
The wheel was designed to last for at least 120 years. It was constructed at the Butterley Engineering plant in Ripley, Derbyshire and then transported and reassembled in Falkirk.
The wheel lifts boats 24 meters, but they must go through a pair of locks to raise them an additional 11 meters to the Union Canal. The wheel has a diameter of 35 meters. Two opposing arms extend 15 meters beyond the central axle. The arms are in the shape of a Celtic-inspired, double-headed axe.
Two diametrically-opposed water-filled caissons are located between the ends of the arms. The caissons always carry a combined weight of 500 tonnes in water and boats. A computer control system regulates the water levels on each side. The caissons can hold up to four 20-meter-long canal boats.
The machinery that drives the wheel is located in the aqueduct’s final pillar. The transformers are on the ground floor. A standby generator and switchgear are on the first floor in case the main power supply fails. A pair of hydraulic pumps that drive the hydraulic motors are located on the ground floor. Ten hydraulic motors supply power to the axle and double as brakes. A 100:1 gear system is connected to each motor to reduce the rotation speed.
A gearing system causes the caissons to turn at the correct speed and to stay correctly balanced. The ends of the caissons are supported on small wheels that run on rails on the inside face of the holes at the ends of the arms. The large central gear is loosely fitted over the axle at the end with the machine room and held in place to keep it from rotating.
Two smaller gears are fixed to each of the wheel’s arms at the end with the machine room. The motors rotate the central axle, the arms swing, the small gears engage the central gear, and the smaller gears rotate at a faster speed than the wheel in the same direction. The smaller gears engage large ring gears at the ends of the caissons and turn them at the same speed as the wheel but in the other direction. This movement cancels the arms’ rotation and keeps the caissons stable and completely level.
Since the load changes as the wheel rotates in opposite directions, some sections of the lift experience total stress reversals. The sections were bolted rather than welded to avoid fatigue and cracks.
A visitor center is located near the lower basin. Visitors can take boat trips approximately every hour. About 400,000 people visit the Falkirk Wheel every year.