Giant offshore crane from Liebherr
By Euan Youdale10 July 2009
Liebherr has delivered the first of its giant 1,600 tonne capacity MTC 78000 heavy lift offshore slewing cranes.
The company's biggest crane to date was installed on the heavy load vessel OSA Goliath at Liebherr's maritime crane factory at Rostock in Germany. Two 208 tonne capacity Liebherr LHM 600 mobile harbour cranes were used in tandem for the assembly, carrying out lifts of up to 400 tonnes each. OSA Goliath will be delivered to Mexican purchaser Oceanografia. Liebherr has received orders for three further units, it says.
The MTC 78000 offers its maximum lifting capacity of 1,600 tonnes at up to 35 m radius. This corresponds to a maximum dynamic load moment of 78,000 tonne-metres, with the crane still being able to slew 360°. The boom length of the first unit is 87 m. At a maximum radius of 74 m for the main hoist, the crane achieves a lifting capacity of almost 530 tonnes. In addition to the main hoist, the MTC 78000 offers two auxiliary hoists with lifting capacities of up to 500 tonnes and 50 tonnes, respectively.
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 tonnes, the slewing ring is about 9 m in diameter. The manufacture of such large mechanical parts needs complicated custom processes, explained Liebherr. Conventional gear cutting machines are only available for large diameter anti-friction bearings up to 5 m diameter. Liebherr, however, has acquired large enough machines and equipment for the mechanical machining of these flanges.
For more information about this crane and its installation see the August issue of IC.