Picking up platforms piggyback

Illustration | Allseas
Marginal Column

Above: This specially designed ship moves platform superstructures in one piece so that disassembly can take place on land.

Illustration: Allseas

July 2012

 

A specially engineered ship can lift and transport offshore superstructures weighing 48,000 tons. This concept reduces both costs and the risks involved.

 
 

To disassemble topsides of offshore platforms, workers used to have to manually disassemble the structure into transportable individual parts on the high seas – work that is both time consuming and hazardous. In the future, the new special vessel from the Allseas Group will completely lift the platforms from their steel “jacket” and transport them onto land, making disassembly considerably safer and more cost-effective. The prerequisite for that decisive simplification is a topside lifting system (TLS), an innovation never before seen in such dimensions. The TLS can lift 48,000 tons, which is equivalent to 80 fully-loaded Airbus A380s.

As engineering partner to the Allseas Group, Bosch Rexroth developed and engineered the drive and control system solution and the major components for the TLS. For Allseas Group Owner Edward Heerema, the engineering is the heart of the project: “We had to lay the foundation for all of the ship’s functions here. That’s why nothing could be forgotten: all technical requirements have to be precisely met and all possible scenarios had to be run through.” To make that happen, Allseas brought a long-term partner on board: Bosch Rexroth. Rexroth possesses comprehensive experience in designing and realizing 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,” as Project Manager Ron van den Oetelaar explains the challenge for Bosch Rexroth. 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.