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Marine Propulsion & Auxiliary Machinery

Marine Propulsion & Auxiliary Machinery

Owners need a plan for reactivating DP vessels

Wed 07 Feb 2018 by Martyn Wingrove

Owners need a plan for reactivating DP vessels
Caption: Alessandro Ciocchi: “Plan for reactivation at the point of putting vessels into layup”

Vessel operators are beginning to reactivate laid up offshore support vessels with dynamic positioning (DP) capabilities as oil companies are loosening their expenditure budgets.

Owners who expect to be reactivating their warm or cold stacked vessels should have planned for it when they were laid up. This was the message from V.Ships Offshore director Alessandro Ciocchi at Riviera Maritime Media’s European Dynamic Positioning Conference in London, on 6 February.

He said vessel owners should have maintained onboard systems and will need to retrain crew and plan for gaining flag and class re-approvals.

He told delegates they should have “planned for reactivation at the point of putting vessels into layup” if they want a smooth reactivation. “It is about management change of systems, personnel and equipment,” he explained.

A key element is the reactivation of onboard DP and power management systems. This involves testing and revalidation during sea trials. The vessel’s failure mode effect analysis (FMEA) documentation validation is also an important requirement.

“Validation of the FMEA is key as it indicates that the vessel is ready to go back to work,” said Mr Ciocchi. He told delegates of two examples of vessel reactivation projects, one involving NOR Goliath in the US Gulf of Mexico and McDermott Amazon in the UK.

Technology plays a key part in vessel reactivations and DP operations in general. Delegates were updated on the latest thruster, energy storage and position reference sensor technologies at the conference.

Schöttel sales manager for tugs and offshore energy Henning Frerichs outlined the processes and computer-based modelling involved in the development of its new thruster VarioDuct. He said four levels of design and optimisation were used, including computational fluid dynamics, and model testing to produce a high-speed thruster that would produce up to 10% more bollard pull.

Voith Turbo vice president for research and development Dirk Jürgens explained how static DP capability plots do not show the reality of operations in North Sea conditions. This was based on studies of offshore vessel operations around Shell’s Brent oil field in different wave conditions.

In another presentation, Corvus Energy senior vice president for business development Halvard Hauso highlighted the fuel savings and emissions reductions from using batteries in combination with gensets. This was demonstrated by Eidesvik’s platform supply vessel Viking Energy. “For one year, it used 21.5% less fuel during port and standby ops and 7.5% lower during transits using batteries,” he said. The vessel had 27% fuel savings in DP mode during one year of operations with Corvus energy storage on board.

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