The world’s largest bearing
Employees in Lippstadt, Germany, manufactured enormous segmental slewing bearings for two drillships. The feat pushed them to their limits, but only in terms of space.
Sperm whales are almost 18 meters long. So are articulated buses and tractor trailers. The width of a four-lane highway with an exit lane is also 18 meters. And that’s the diameter of the world’s biggest slewing bearing. There has never before been a slewing bearing this large. Now thyssenkrupp has manufactured two of them, which were delivered to the customer at the end of 2015.
A Dutch oil-drilling specialist needed the two large-scale bearings for a very particular application: two Floating Production Storage and Offloading (FPSO) units. They are both converted oil tankers that have been retrofitted with special drilling apparatuses. These tankers can easily navigate at sea to offshore oil fields in deep waters. Furthermore, they do not require any costly installation work, in stark contrast to offshore platforms for oil drilling. In addition, the FPSOs can process and store the oil right on board. The customer is equipping the “Olympia” and “Antarctica” tankers for drilling activities 150 kilometers off the southwest coast of Africa. “For the customer, it was sufficient proof of what we are capable of,” explains Anja Quadflieg, Sales Offshore Technology, Tunneling, Cranes at thyssenkrupp.
Lippstadt to Singapore with a stop in Abu Dhabi
Each slewing bearing from Rothe Erde connects one FPSO ship to the oil field. There is a turret-mooring system installed in the ship’s interior, which connects the lines on the ship to the 59 well centers on the seafloor. The FPSO also dynamically positions itself to compensate for currents and rough seas without entangling the pipes.
An initial request was sent by email in the summer of 2013. “The largest slewing bearings that we had manufactured previously were 14 meters,” says Anja Quadflieg, who works in Sales at thyssenkrupp rothe erde and managed the project. “For the customer, it was sufficient proof of what we are capable of.” The bearings were ready at the end of 2015 and shipped to Abu Dhabi where they were reassembled under the close supervision of four thyssenkrupp employees. Once the pipeline turret-mooring system was installed, everything was transported to the Singapore shipyard where oil tankers are being converted into FPSOs.
Bearings should never be any larger than necessary
The contract was demanding for both our technology and logistics. The bearing diameters are generally based on the planned load, yet they should never be any larger than necessary. For this reason, cranes and wind turbines usually have weldless forged rings with diameters measuring up to eight meters. You couldn’t transport them otherwise. In this specific case, the diameter of the lines that the rings needed to fit around were specified. The slewing bearing for the FPSO ship had to be far larger, which meant it needed to consist of segments. Nevertheless, each segment measures six meters.
The hall was just big enough to accommodate this contract.
Assembly was carried out in Lippstadt. Due to the dimensions, this wasn’t so easy. “Our R&D employees had just moved into a new facility, and their previous hall was just big enough to accommodate this contract.” There was only a one-meter leeway in some areas of the building. It drew many onlookers, too. “We proudly showed our other customers what we are capable of handling,” says Quadflieg. She adds, “We could manage bigger. We can manufacture bearings with diameters measuring 25 meters, too.”