Stoof developed the first giant containerisable heavy lift device built by Mammoet, the MSG-50. The company followed this with the MSG-80 and PTC cranes.
Stoof first floated publicly the idea of an even bigger containerisable lifting device in the pages of Cranes Today (October 2013, p10, Man with a plan). At the time, the proposal was for a 10,000t device. Many elements of the original idea, in particular the sliding footing of the device and a self-erection system that allows the crane to be mobilised in limited space with no assist crane, remain.
The Focus can be fully assembled on site in confined areas. The whole assembly process takes place in vertical direction as opposed to conventional assembly of cranes which is usually on the ground. There is no need for auxiliary cranes as lifting capacity is integrated into the design.
The crane footing is designed to move back and forth and in rotation around the backmast, even when loaded. Depending on its configuration, the Focus can lift up to 24,000t.