Montague Dock - 2 - Cranes

The time period is the 1960s when crane systems were still largely mechanical with simple electric control gear and certainly not computer controlled.

The two gantry cranes on this dock are two versions of an old Trix (WIAD) model of a Krupp Ardelt level luffing crane, one (without markings) is believed to be a pre-production model and the other a production model. Both were bought pre-assembled, a little worse for wear needing some minor repairs including some slight age distortion of the crane jibs, but nothing serious.

Although probably based on German prototypes very similar cabins could be seen on UK cranes in the 2oth century, some had these 'horse head' mechanisms and others had cleverly arranged pulley systems to keep the hooks at a constant height by adjusting the amount of cable that was paid out dependent on the jib angle.

These distinctive type of cranes were developed to allow easier positioning of loads particularly near the ground.

In the case of the horse head types that these old Trix models represent the geometry of the jibs with the swinging and counterbalanced top member allows the main jib to be raised and lowered (luffing) to swing loads horizontally whilst maintaining the height of the hook at a constant height.

Hence they are called level luffing cranes, well suited to loading and unloading of ships where precision is required when moving heavy loads in confined spaces and many dock workers were close to the movements. More information may be found at Ref 2.1.

This is the early pre-production version




The later production version




Top view of both




Both placed to confirm how they would fit on the dockside, the cargo vessels shown would in fact be further away from the crane when the dock walls are put in place.




A basic form of inlaid tracks for them to traverse on has yet to be laid, this will be part of the dockside surface work.

Jim

References

2.1 Level luffing cranes - https://en.wikipedia.org/wiki/Level_luffing_crane

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