At the end of June, Liebherr delivered the first heavy lift offshore crane type MTC 78000 straight from its manufacturing plant in Rostock. The MTC 78000 is one of the biggest offshore slewing cranes worldwide. With a maximum dynamic torque of 78,000mt, the MTC 78000 is the most powerful machine within the extensive range of cranes and material handling machines offered by the Liebherr group of companies. Four units of the new heavy-lift crane have already been ordered to date.
Despite its size, the MTC 78000 has been designed as a slewing crane and is supported by traditional large-diameter anti-friction bearings. With a weight of 70t, the swing ring has a diameter of approximately 9m.
The onsite erection and assembly of the large size crane on the heavy load vessel OSA Goliath presented Liebherr engineers with special challenges – for example, the planning of the individual hoists so that the maximum permitted ground pressure of the pier was not exceeded. As the assembly starting date depended on the arrival of the heavy load vessel and the required lifting equipment needed to be ready on short notice, Liebherr exclusively used their own cranes for the assembly.
Two large LHM 600 mobile harbour cranes were used in tandem operation for the heavy duty lifts. Both cranes with their maximum load capacity of 208t enabled parts weighing up to 400t to be mounted in tandem operation. The machines were equipped with the recently patented innovative Liebherr ‘sycratronic’ control system. In combination with the dynamic anti collision system the ‘sycratronic’ controls the simultaneous operation of the mobile harbour cranes, so ensuring best possible performance and protection for the cranes.
The assembly of the MTC 78000 required several spectacular heavy duty lifts. First, the slewing platform was mounted – at 370t, the heaviest of the components. Thereafter, the machinery compartment with the drive components (approximately 240t), the mast lower section (about 250t) and the mast upper section (around 160t) of which the lowest point needed to be hoisted up to over 43m above the pier level. This hoisting height was made possible by equipping the mobile harbour cranes with two corresponding tower extensions.
The last step in the assembly process involved putting the boom in place. In a tandem hoist operation, the 87m boom was positioned with millimetre precision at the respective connection points enabling the boom to be pinned to the slewing platform on both sides. The sheer size of the pins required a specially developed hydraulic pinning machine.
Due to precise project planning, the specially trained team of 50 mechanics was able to assemble the MTC 78000 in only 23 days.