ESCO Couplings has been selected to participate in the implementation of one of the world’s tallest boat lifts. The Strépy-Thieu boat lift was originally built to connect the “Canal du Centre” in Strépy-Thieu, and its important transportation of locally mined coal and iron ore, to the canals reaching the main ports of Belgium.

Connecting the canals has been a huge technical challenge. The only possible track was very meandering and with high graduation of slope - 66 meters. Building “locks with deep drop” was impossible, decision was thus taken to build hydraulic boat elevators, and from 1888 until 1917, 8 ship-elevators were built, hydraulically driven by the power of the water of the canal only.

In early 1950s, due to economic growth, the Canal du Centre had to be adapted to allow the passage of 1,350-tons ships. The Walloon technical services designed a unique boat elevator to overcome the high slope gradient, capable of lifting larger boats and to cover the 74 meters-high in one vertical movement.

The Strépy-Thieu boat lift was build on a branch of the Canal du Centre. With a height difference of 73.15 meters between the upstream and downstream reaches, it was until recently the tallest boat lift in the world.

How does it work exactly? The lift consists of two independent counterweighted caissons which travel vertically between the upstream and downstream sections. Due to Archimedes' Principle, the caissons weigh the same whether they are laden with a boat or simply containing water. In practice, variations in the water level mean that the mass of each caisson varies between 7,200 and 8,400 tones. Each caisson is supported by 112 suspension cables (for counterbalance) and 32 control cables (for lifting/lowering). 4 electric motors power 8 winches per caisson via speed-reduction gearboxes and the 73.15-metre lift is completed in 7 minutes. The structure is massively reinforced to provide rigidity against torsional forces during operation and has a mass of approximately 200,000 tones and flexibility for seismic issues.

Esco Couplings was selected to supply the 28 units floating shaft Escogear couplings FFS 240 connecting the driving systems.