Mammoet says that it was recently contracted by shipbuilder and ship repair company Damen Shiprepair to assist with a jackup leg repair for the Noble Corporation drilling rig Noble Regina Allen.
Initially planned to be completed using one of Mammoet’s PTC large ring cranes, the project was instead performed by jacking-up the 22,000-ton drilling rig.
“The first option we presented was performing the lift using a Mammoet PTC210 crane,” explains Ruud Jansen, Commercial Manager at Mammoet. “It would see the crane positioned on the quayside and lifting and lowering the leg into the vessel from above.”
“The second approach was to bring a small crawler crane onto the deck of the vessel and have the repair carried out from above. The third solution was to lift the vessel using Mammoet’s Mega Jack 5200 system and carry out the repair from underneath.”
“We had to act quickly,” said Mammoet Project Manager René van Lint, especially since the drydock was only available for a relatively short period of time. “Whereas normally we assemble the Mega Jack system in 15 days, we realized that we would have to do it in seven days. To achieve this, we scaled up and accelerated the schedule. This was possible due to our large fleet of equipment and by having a team of experts working in two shifts.”
The drydock was prepped and support blocks installed on its base before the 22,000t rig was floated inside. The dock was then drained, and the rig lowered onto the blocks. The team was then able to install the equipment underneath.
A configuration of six towers of the Mammoet Mega Jack 5200 were used, each with a capacity of 5,200t. Small mobile cranes and forklift trucks were used to assemble this equipment. Once all the jacks were in place, the rig was lifted to a height of 35 meters.
Because the leg section measured 70 meters tall, it was cut into two parts to fit underneath the rig. Each section was moved into position using Mammoet Self-Propelled Modular Transporters). The first section was driven into position under the rig and then lifted by the rig’s jacking mechanism.
The process was then repeated for the second section, which was welded to the first by Damen Shiprepair, forming the complete jacking leg. With this flexible approach, Mammoet says that the necessary workers and equipment were able to carry out the repair work in just three months.
