Special vessel lifts offshore platforms in one piece

Paul Boughton
As the major engineering partner to the Allseas Group, Bosch Rexroth has developed a drive and control system for the world’s largest mobile lifting mechanism for offshore installations.

The special vessel equipped with this topside lifting system (TLS) known as ‘Pieter Schelte’, can lift and transport topsides of offshore platforms with a weight of up to 48,000 tons, all in one piece. This Allseas solution therefore considerably lowers the cost and risk of offshore assembly and disassembly. Pieter Schelte is currently being built in South Korea and will be ready for use in early 2014.
To disassemble topsides of offshore platforms, workers would traditionally have to manually disassemble the structure into individual parts whilst at sea – work that is both time consuming and hazardous. The new vessel from the Allseas Group will completely lift the platforms from their steel 'jacket' and transport them onto land, making disassembly much safer and cost-effective.

For Allseas Group Owner Edward Heerema, the engineering from Bosch Rexroth is at the heart of the project: “We had to lay the foundation for all of the ship’s functions. That’s why nothing could be forgotten: all technical requirements have to be precisely met and all possible scenarios had to be run through.”

This is exactly why Bosch Rexroth was introduced to the project;maxmizing its comprehensive experience of designing and developing challenging drive and control solutions for offshore installations and maritime applications. An international team made of industry specialists and technology experts developed a TLS drive and control system, based on the principles as provided by Allseas. “No comparable system has ever been created before, making this an exciting task, even for our experienced engineers,” comments Allseas Project Manager Ron van den Oetelaar.

In complex co-simulations, Rexroth reviewed the design and dimensioning of major components with a continuous focus on adhering to high safety standards. The company-owned software takes both mechanic strengths as well as specific hydraulic characteristics into consideration. In addition to engineering products and services, Rexroth also supplies the five-megawatt central hydraulic power unit as well as numerous key components and subassemblies for the TLS. The new special vessel is currently being built in a South Korean shipyard and is set to begin disassembling the first offshore platforms in early 2014.

For more information, visit www.boschrexroth.co.uk

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