Dutch international heavy lift company Mammoet and Stoof Engineering and Innovation are jointly developing a new ultra heavy lift crane with a capacity of up to 24,000 tonnes.
Dubbed the Focus, Mammoet claims it will have a maximum load moment of 1.5 million tonne/metres. One of the main features of the new crane is that it can self-erect vertically without the need for additional cranage, even when the main boom is more than 200 metres long.
Details on the self assembly procedure are still a little scarce, but it seems that the process begins by installing a vertical lattice tower with a davit crane on top. Once the tower has reached full height it hoists up the twin derrick boom/back mast section by section and then does the same with the twin boom assembly. The tower then serves a heavy duty pendant/link from the top of the back mast to the counterweight.
The crane is said to have a fast erection/dismantling time as well as being manoeuvrable and being containerised is easy to transport.
The distance between the foot of the boom and counterweight can be varied with a load on the hook and it can be done while the crane is slewing, quite how it 'slews' - given that the boom back mast pivots appear fixed - is not yet clear.
The ballast radius can be increased and because the ballast is suspended vertically from the top of the back mast it is able to be positioned over sizeable obstacles to carry out the lift.
Piet Stoof - founder of Stoof E&I - is a former technical director of Mammoet who designed the MSG 50 (Mammoet Sliding Gantry) in 1996 which had a maximum load moment of 50,000 tonne/metres. The MSG-50 claimed to be the first machine with containerised masts and components. The crane was the forerunner of the MSG 80 ring crane (80,000 tonne metres) followed by the containerised PTC ring cranes with load moments up to 200,000 tonne metres.