Cowans Sheldon 50 ton Dockside Crane

After the famous blocksetting crane, this must surely be one of the most beautiful in the world. The picture shows the crane based at the Sturrock Graving Dock in Cape Town. The famous Table Mountain is in the background. This crane was ordered by the British Admiralty in 1940 for the newly completed giant dry dock in Cape Town, South Africa, and was to be used to service warships and transports during their long voyages round the Cape during the second world war. Two more are to be seen in the Devonshire Dockyard.

The Cape Town crane has been a source of inspiration and wonder. After the war, it effortlessly lifted locomotives and boilers after their long voyages from Europe, and has ben carefully maintained over the decades. Soon to celebrate 60 years of service, she is in as good a condition now as the day she was put into service, and is a tribute to her Carlisle builders and the South African Transport Services who have handled and mainted her.

A first attempt at building this crane was made in 1965. The result is shown in the picture. The horizontal membersof the base structure were 12 1/2" angle girders. This crane was successfully controlled by radio. A single channel was used, and this actuated a post office sequential relay, which clicked from a resting position through nine positions to the tenth which returned it to the first resting position. This left eight position in between, and each enabled the forward and reverse control of 4 motors. These were for travel, slewing, luffing and load. One had to be careful to give the right numberof clicks for the required action. But it worked.

It was always a challenge to return to this model. Plans were kindly sent from Cowans Sheldon and rebuilding was started in 1992, and considerable progress was made. The intention was to build a very large model, along the lines of the famous giant blocksetter.

There are a number of special features of the crane. If one looks carefully at the jib, it can be seen that it is luffed by means of two large vertical screw rods, which actuate a counter-weight running in rails. The top of the jib is tied to this counterweight by tie link rods. Theother noteworthy feature is the bogies. There are four of them, each with four wheels to distribute the weight, and they enable the crane to run round a curved track The drive is taken through the central bearing, a very hard feature to model in Meccano. The roller bearing should present no problems, the answer of course being part 167. There are twin pulley blocks, which can be linked together for especially heavy loads.

One can see the model taking shape in the photo. Strict attention was given to scale, and a special feature was the attempt to copy the original mechanisms. This meant the same motor positions and gearing where possible. No-one knows if this monster model will ever see the light of day, but it is a love affair which has lasted nearly a lifetime.

Michael Adler - May 1999