Recently, the second unit of the 1.600 t heavy lift offshore crane MTC 78000 was delivered from its manufacturing plant in Rostock.

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 70 tons, the swing ring has a diameter of approximately 9 m. The manufacturing of such large mechanical parts can only be accomplished through complicated custom processes as conventional gear cutting machines are only available for large-diameter anti-friction bearings up to a diameter of 5 m. Therefore, Liebherr has acquired correspondingly sized machines and equipment specifically for the mechanical machining of these flanges.

The onsite erection and assembly of the large size crane on the heavy load vessel OSA Sampson posed special challenges. 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 208 tons each enabled parts weighing up to 400 tons 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 370 t, the heaviest of the components. Thereafter, the machinery compartment with the drive components (approximately 240 t), the mast lower section (about 250 t) and the mast upper section (around 160 t) of which the lowest point needed to be hoisted up to over 43 m 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 87 m boom was positioned with millimeter 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.

A big challenge posed the rope assembly of four 1.6 km long boom hoist winch and lifting ropes which was handled with special auxiliary devices and high work input to finally fit the crane with the 60 t main hook.

Parallel to the assembly of the heavy lift offshore crane an offshore crane with a maximum lifting capacity of 100 t was installed on the heavy load vessel OSA Sampson.

As the base column of the crane also had to be welded with the vessel the mechanics decided to assemble the crane on the test stand in Rostock before the vessel arrived to lift and install the complete crane on board. This procedure reduced the duration of the project considerably. The crane transport from the test stand to the vessel was accomplished with a suitable platform trailer.

Due to precise project planning, the specially trained team of 50 mechanics was able to assemble the MTC 78000 in only 23 days.

The MTC 78000 is one of the biggest offshore slewing cranes world-wide. With a maximum dynamic torque of 78,000 mT, 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.