11th January, 2018 in Maritime, Transport & Industry

The Falkirk Wheel: Building a waterway wonder

By John Laverick Fellow of the Institution of Civil Engineers

In 2002, British Waterways (the government department that managed Britain’s canal network at that time) conducted a poll of those interested in the inland waterways, asking them to choose the ‘Seven Wonders of the Inland Waterways for the 21st Century’. The Falkirk Wheel in Central Scotland was chosen as one such wonder.

The 220km canal network in Scotland was built between 1768 and 1822. It consists of the Caledonian, Crinan, Forth & Clyde and Union canals. Although small in number, they are some of the most famous and historic waterways in Great Britain. The Caledonian Canal between Fort William and Inverness, for example, makes use of the whole of the length of Loch Ness, so a cruise along that waterway might reveal a monster for which you did not bargain.

The Falkirk Wheel, which links the Forth & Clyde Canal to the Union Canal in Central Scotland, was built during the twenty-first century as part of a restored waterway route right across Scotland from the Atlantic Ocean to the North Sea.

In recent years, British Waterways has reversed years of neglect and has revitalised Scotland’s canals, transforming them into an important national asset. More and more Scots and visitors to Scotland are discovering that canals are the perfect way to explore Scotland’s wonderful countryside. Part of this revitalisation included the construction of the Falkirk Wheel, which was designed to reconnect the Forth & Clyde Canal to the Union Canal, the eastern terminus of which is right in the centre of Edinburgh.

An exceptional feat of modern engineering, the Falkirk Wheel is already recognised as an inspirational sculpture for the twenty-first century. This elegant mechanical marvel, the only rotating ship lift in the world, was opened on 24 May 2002 by Her Majesty Queen Elizabeth II as part of her Golden Jubilee celebrations. Sad to say, the royal opening was delayed by a month due to extensive damage of the wheel’s electrical systems – the work of local vandals.

The Falkirk Wheel is sited in a natural open amphitheatre at Rough Castle near Falkirk, where visitors can enjoy the ‘Falkirk Wheel Experience’ by cruising on special passenger boats and by visiting the distinctive new visitor centre located at low level beneath the wheel. The centre provides a sensational view of the rotating mechanism through its glass roof, and a one-hour boat trip takes the visitor on a ‘rotating’ journey to the top of the wheel and back again. Extended boat trips along the two canals are also available.

These canals were previously connected by a flight of eleven locks, which, by the 1930s, had fallen into disuse (they were filled in and the land built upon). The plan to regenerate the canals of central Scotland and to reconnect Glasgow with Edinburgh by water was led by British Waterways, with support and funding from the Scottish Enterprise Network, the European Regional Development Fund, the Millennium Commission and seven local authorities. A decision had been made very early on in the regeneration planning process to create a dramatic twenty-first-century landmark structure to reconnect the canals.

The difference in the levels of the two canals at the Falkirk Wheel is 24m. However, the Union Canal, which runs on one level all the way from Edinburgh, is at a higher level than the top of the Falkirk Wheel and so boats have to pass down through two new locks to descend from the canal onto the wheel’s approach aqueduct. The reconstructed end of the Union Canal had to be lowered in order to pass under the historically important Roman Antonine Wall and also under the main Edinburgh–Glasgow railway line, both of which cross the boundary of the site.

The mechanism that ensures that the tanks containing the boats remain upright whilst the wheel rotates is quite simple. The large gear wheel ‘A’ is a fixed stationary ‘sun’ gear attached to the supporting structure. As the wheel rotates in a clockwise direction, the idle ‘planet’ gear meshes with the fixed ‘sun’ gear as it rides around its periphery, causing it to rotate in a clockwise direction pushing gear wheel ‘B’, which is connected to the tank containing the boats, in the opposite direction to the rotation of the wheel, thereby keeping the tank upright at all times. Irrespective of the number and size of vessels in either tank, the wheel is perfectly balanced at all times, obeying Archimedes’ principle; as the designed rotational speed is comparatively slow, the power needed to turn the wheel, just to overcome friction, is around 5–12 kilowatts or about the same as that required to boil three or four kettles of water.