Safety and technical issues, vessel simulation and future solutions were debated during a lively start to Riviera Maritime Media’s European Dynamic Positioning Conference, in London, UK, 7 February 2023
In his opening address, conference chairman and Sandercott Project Engineering offshore dynamic positioning (DP) consultant and director, Steve Sandercott, briefly outlined current trends in DP systems and vessels. He also highlighted the status of existing DP technology, the introduction of standards, regulations and guidelines, and the development of novel concepts.
He said key issues with current DP systems include low-quality failure mode effect analysis, lack of knowledge on fault alarm limits for propulsion thrusters, gyrocompasses and other sensors and a shortage of anomaly logging with DP systems.
“We need a longer snapshot of DP performance, so if a gyro drops out, this event is logged and put in a file,” said Mr Sandercott. This data could be used for trend analysis.
DNV principal specialist for DP simulations Luca Pivano explained how digital twins and vessel simulations can help design and develop DP systems on offshore windfarm service support vessels (SOVs).
Simulations can provide information on the optimised positioning of an SOV with a walk-to-work gangway on an offshore wind turbine foundation. They can also help “analyse the full mechanical limits of gangways for staying connected for people transfers,” said Mr Pivano.
In another project, DNV simulations were used to compare fast-response thrusters with traditional azimuth thrusters during DP performance. It was found “fast-response thrusters give improved DP performance, but require quicker power, so batteries could be used for producing power quickly,” said Mr Pivano. “But, faster actuator response needs faster controllers and wave filters.”
DNV also used simulation programs to study sudden gangway disconnections and discovered SOVs can be affected by short period waves, which result in challenging load dynamics on DP systems.
“Therefore, it is critical to analyse vessel performance with actual site conditions,” said Mr Pivano, including weather and sea states.
ABL Group principal engineer and DP surveyor Nitin Thulkar discussed different configurations of hybrid power systems, including batteries with generator sets and/or fuel cells, for DP vessels. He explained the challenges of managing power and energy from multiple power sources, the design issues in battery sizes for DP vessels and safety aspects of operating batteries.
Benefits of using batteries include reducing fuel costs and genset running hours, and providing redundancy in DP systems. But there are issues to solve and improvements to be made in terms of reducing costs and raising the energy density of batteries, integrating batteries into vessel power management systems and reducing safety risks.
“The way forward is to reduce the risk of fires and explosions, doing research into increasing battery density and chemical safety polymers, developing green offshore charging stations and introducing floating anchor areas for vessels,” said Dr Thulkar.
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