Tub boat lift
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Tub boats are small boats used to transport coal and other minerals, sometimes working singly, sometimes in long trains. When it is required to move them between different elevations of canal, locks, boat lifts and inclined planes have all been used in various locations around the world. One type of boat lift is specific to tub boats however; it is this type of lift which is described here.
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[edit] Tub Boat Lifts
A tub boat lift (German: Kahnhebehaus) is a type of boat lift in which the boats are lifted out of the water. Most other types of boat lift are designed to move the boat afloat in some kind of water-filled tank, and, apart from maximum dimensions, are not restricted in the type of craft transported. These tub boat lifts can only lift a specific type of boat which in its turn is designed to be lifted by a specific design of lift.
[edit] Operation
On some canals, tub boat lifts were used instead of locks or inclined planes to overcome differences of elevation. These consisted of a moveable hoist travelling on four toothed wheels engaging with two toothed wooden rails, one mounted on each supporting wall. The hoist possessed two drums around which the lifting cables were wound. The lifting ropes passed through pulley blocks before being attached to lifting eyes on the boats to make the lift easier. Four men would wind the hoist when lifting a full 2.5 to 3 tonne tub boat until it was high enough to pass over the dam of the upper canal.
[edit] Examples
The remains of two tub boat lifts can still be seen, in the same region of Germany.
- The Halsbrücke tub boat lift (also known as Rothenfurther Kahnhebehaus), was built in 1788/89 on the Freiberger Mulde. The remains of the Halsbrücke lift and the connecting section of the upper canal were restored in 1988. The tub boats used in this case were 8.5m long and 1.6m wide and when first used carried 2.5 tonnes, upgraded to 3 tonnes later in the canal and lift's working life. This lift worked until 1868.
- The Großvoigtsberg tub boat lift (also known as Christbescherunger Kahnhebehaus), in the neighbourhood of Freiberg, Saxony, was built in 1791 to overcome the difference in elevation between the Mulde and the Christbescherung mine canal. This canal was not completed, it is therefore possible that this lift was never used. The engineer in charge of the construction of both of these lifts was the Freiberg Kunstmeister Mechanicus Johann Friedrich Mende (1743-1798).[1]
[edit] Further Reading
- Uhlemann, Hans-Joachim (2002). Canal lifts and inclines of the world, English Translation, Internat. ISBN 0-9543-1811-0.
[edit] References
- ^ Hans-Joachim Uhlemann. Canal Lifts and Inclines of the World.
