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Tour de Ruhr

The Henrichenburg Boat Lift

In 1899, when the German Emperor Wilhelm II inaugurated the Henrichenburg Boat Lift in Waltrop, it was the absolute state of the art in hydraulic engineering. The biggest & most spectacular structure on the Dortmund-Ems Canal, it hoisted barges with a tonnage of up to 750 over a distance of 14 metres in 2½ minutes. The alternative solution would have been a staircase lock with two or three chambers, but a boat lift was much faster to operate & cheaper to build. Two things make this lift special — its lifting power came from five submersible floats, and its architecture is strikingly Prussian. In 1962 the lift was replaced by a bigger one, and a year later it was found that the caisson had tilted, and that it could no longer be moved into either the fully up or fully down position. Since 1992, the Waltrop boat lift has been a museum.

The technology is pretty impressive. The lift consists of a caisson, under which are five floats, each immersed in a 33½-m-deep well. Together the floats have a buoyancy of some 3,050 tonnes, which is the weight of the water-filled caisson, and because the two are in equilibrium, all that is required to get the lift moving is a 150-hp motor to overcome friction. This motor lacks the power to move the lift all the way up or down, but it doesn’t have to: once the lift has moved a few centimetres, the caisson & canal gates open simultaneously, briefly, to allow water out of (downstream) or in to (upstream) the caisson to upset the equilibrium, and then the lift moves up or down purely as a result of its change in weight. The entire process is guided by four vertical spindles, each 24⅗ m long and 28 cm in diameter, one at each corner of the framework, which revolve simultaneously to keep the caisson level, and act as a brake when the gates are being opened or closed.

Reader comments

Arnulf

After it was decided in 1979 that the Henrichenburg Ship Lift would become part of the Westphalian industrial museum, it was restored & reconstructed without bringing it back into use. Today, the caisson is in a fixed position, which allows visitors to inspect the construction from close by. The exhibition in the former boiler & engine house explains how the ship lift works. On board the barge Franz-Christian, in the lower dock, an exhibition explores the lives of the boatmen & their families who sailed the inland waterways.

Emma

I don’t understand why the caisson doesn’t move down when a big boat enters? If 150 hp is not enough to move the lift all the way up or down, how can the motor be strong enough to keep the caisson from falling?

Rolf

As Archimedes pointed out, a floating object displaces an amount of water equal to its weight. So if you add 600 tonnes of floating boat to the caisson, then 600 tonnes of water flows out to the canal, which means the caisson weighs the same no matter how heavy a boat enters it.

Dirk

If you want to see a boat lift in action, the Niederfinow Boat Lift on the Oder-Havel Canal is the place to go. Built in 1934 to negotiate a height difference of 34 metres, it’s still working today, making it the oldest operational ship lift in Germany. The caisson weighs 4,290 tonnes and hangs on 256 steel cables connected to 192 concrete counterweights.