Damen designs decom vessel

Dutch firm Damen Shipyards Group has announced its latest concept design: the Damen Decommissioning Series.

The vessel will specialize in three core areas of the oil and gas decommissioning sector: topside decommissioning, offshore platform removal (up to 1600-tonne), and subsea cleaning and removal. The design is based on in-house research carried out at Damen by one of its undergraduate interns.

Justin Rietveld, studying Maritime Technology at the Rotterdam Mainport University of Applied Sciences, was given a brief to investigate the potential niche markets for new vessel designs in the oil and gas decommissioning sector.

“This research started off with the idea of developing a decommissioning vessel based on Damen’s existing portfolio,” says Rietveld. “However, we soon found out that this market needs more.

“For example, there are many different activities within the decommissioning sector. This vessel can support a vast number of those. We have developed a concept to cover the bigger part of this new and exciting market.”

The vessel’s monohull design has a split stern; a characteristic that will come into play during platform removal operations, explains Mr Rietveld: “This ship will be able to reverse up to a jacket, where it will be ballasted to sink below the platform. Upon deballasting, the vessel will rise up to pick up the platform.”

The preliminary estimations of the vessel’s capabilities show that it will be able to perform decommissioning of fixed platforms of up to 1600-tonne in weight. This figure signifies a significant amount of global fixed platforms, and over half of those in the North Sea, says Damen.

The concept design includes modular add-ons to address the possibility that such a vessel will not be solely active in the decommissioning market. This versatility will ensure that owners can optimise productivity: bridging the potential gap between decommissioning contracts with other roles.

These modular additions to the existing design include the (temporary) installation of a crane or a helideck. Functionality can be further boosted with the addition of accommodation modules to increase personnel capacity. Another option will be the addition of a temporary platform to create a solid stern. The subsequent increase in deck capacity could be used for transporting and installing monopiles and foundations for the offshore wind industry.