Verifying hull performance and gathering oceanographic data will help owners define their antifouling strategies and reduce fuel costs
Monitoring hull performance and antifouling systems can help optimise ship operations and reduce expenditure on fuel and coatings. Technology can assist shipping companies gain a greater understanding of the condition of their hulls and the impact on bunker consumption, enabling better decisions on antifouling products, applications and drydock scheduling, according to Chevron Shipping Co hull and coatings engineer Johnny Eliasson.
Mr Eliasson offered a ship operator’s perspective during Riviera Maritime Media’s Separating hype and hull coatings webinar, which was held as part of Riviera’s Marine Coatings Webinar Week on 8 July.
Mr Eliasson said managing hull performance and choosing the correct antifouling is complex and needs ship-specific information. “Monitoring is critical,” he said, adding that an antifouling process would include hull cleaning, propeller polishing, surveys and coatings.
“None of the solutions will fit all ships,” said Mr Eliasson. “A strategy for hull management is ship-specific.”
He said ship operators need to consider the operational profile of the vessel and monitor the hull condition and speed profiles of ships before making decisions on antifouling techniques and coating requirements.
Safinah Group general manager for marine consulting Carl Barnes agreed that antifouling strategies should be ship-specific and require performance monitoring.
“All vessels are different and fouling control selection should be specific to the ship and not generic specifications,” he said. “For selecting antifouling products, a real understanding of in-service fouling risk is the first key thing,” said Mr Barnes.
So is understanding product performance related to specific fouling risk, as there are more than 100 products available from major suppliers, he said.
“Will they work as expected on the hull?” Mr Barnes asked. To answer this, owners need in-service information. “Understanding whether the product works by monitoring the performance of the vessel is key,” he said.
Monitoring should include vessel speed, position in the world’s oceans and its activities, as there are 66 large marine ecological regions with different temperatures, water salinity, illumination, nutrients and biofouling levels.
Information on hull performance should then enable owners to select the drydocking period, processes and antifouling products to minimise in-water friction and thus fuel consumption and expenditure.
Jotun Performance Coatings global concept director for hull performance solutions Stein Kjølberg also said performance data and product information were important to inform shipowners’ antifouling decisions.
“We have learned a lot by utilising data and analysis to properly understand what impacts performance,” said Mr Kjølberg. “Owners should get to grips with the performance of the vessel and go forward from there.”
Vessel performance data is increasingly required for the European Union’s monitoring, reporting and verification of CO₂ emissions and IMO’s data collection system for fuel consumption. Owners can use data to maximise fuel efficiency, said Mr Kjølberg.
Data will also be required for other stakeholders. “Charterers, banks, insurers and brokers are only some of these that now take an active interest, and they are all pushing for more efficiency and transparency,” said Mr Kjølberg.
Jotun has introduced a path to maximum hull efficiency as a method of reviewing the factors that affect performance. This begins with hull surface preparation through grit- or hydro-blasting and investing in premium coatings: “[These] function well for two to three years, but then we start to see a drop,” said Mr Kjølberg.
The coating application is also important as surface roughness from improper application “can have a severe impact on the speed penalty and fuel consumption of a vessel,” he said.
Ship operators can use monitoring data to optimise specifications. “Using available data to define the effective operational parameters means the correct antifouling and film thickness is used for the individual vessels,” Mr Kjølberg said.
“Performance monitoring is key to learning as much as possible about how to improve efficiency,” he explained. “Any use of performance monitoring is useful, whether this is more advanced or just noon reports.”
Information gathering will include assessing oceanographic and environmental conditions throughout the year as “conditions like surface temperatures and level of nutrients change over a year,” said Mr Kjølberg.
Operators can examine the operating profile, vessel activity and use the environmental information to refine operations where appropriate.
“Using oceanographic data means it is also possible to gain advice on where a vessel should stay idle if it has to,” said Mr Kjølberg. “It will not remove the fouling challenge but could definitely reduce it.”
This can be used for a fouling exposure assessment, with knowledge of where the vessel trades. “It is then possible to predict when the risk of fouling reaches a certain level, and then take the necessary precautions,” he added.
When fouling is unavoidable, it needs to be treated in the most proactive manner possible, and these decisions can be aided through computer processing.
“Using fouling prediction algorithms means it is possible to take initiatives as early as possible,” said Mr Kjølberg, “and sometimes even before fouling develops into a critical stage.”
Guided by data
Consulex principal consultant and NACE International president Terry Greenfield agreed decisions on installing and maintaining coatings should be guided through data.
“Operators make good decisions based on the data collected, the performance monitoring and the testing done to qualify materials,” said Mr Greenfield.
Data can also be collated on new solutions and their application. “New technologies and solutions typically present an accompanying new set of problems that will manifest as we learn to install and maintain them,” said Mr Greenfield.
The approach to installing and maintaining systems will affect the success of these solutions. “Ultimately, the maintenance of the systems will have a lot to do with success,” he said. “The more complex the coating, the more complex the installation can be, with its own unique set of issues.”
Mr Greenfield recommended operators plan through information and data processing. “Consider what can happen and plan accordingly,” he said. “Pay attention to learn and capture the lessons and have complete management that includes design and selection, installation, quality control and maintenance.”
All this requires knowledge that comes from data. “Make decisions through performance monitoring and testing products,” said Mr Greenfield. “This approach will affect the success of an antifouling system.”
Environmental regulations will impact ship coatings
Ship hull coatings will come under greater scrutiny this decade as more regions and nations tighten regulations covering antifouling system application and use.
During the Separating hype and hull coatings webinar, Reed Smith partner Peter Glover explained the regulatory aspects of antifouling and coatings. He described the changing legal landscape as new environmental regulations are introduced that affect antifouling techniques and products.
“The environmental considerations will need to be managed,” he said. “We will see more regional responses to biofouling guidelines and conventions,” said Mr Glover.
Regulation on antifouling started with the United Nation’s Convention for the Law of the Sea, which came into force in 1982. This states: “Nations shall take all measures necessary to prevent, reduce and control pollution of the marine environment resulting from the use of technologies under their jurisdiction or control, or the intentional or accidental introduction of species, alien or new, to a particular part of the marine environment, which may cause significant and harmful changes thereto.”
This included using antifouling to prevent the introduction of invasive aquatic species through global maritime trade. Since then, guidelines and conventions have been introduced changing the legal landscape. Prime among these is IMO’s International Convention on the Control of Harmful Anti-fouling Systems on Ships (AFS). Further to this, IMO produced guidelines for survey and certification, inspection and brief sampling of anti-fouling systems on ships. It also published guidance on best management practices for removing antifouling coatings from ships, including Tributyltin (TBT) hull paints in July 2009.
Mr Glover said the AFS Convention has been transposed into EU legislation under Regulation (EC) No 782/2003 on the prohibition of organotin compounds on ships. “The AFS Convention is focused on preventing adverse impacts from using antifouling systems and the biocides they may contain, rather than preventing the transfer of invasive aquatic species,” says Mr Glover.
For that, IMO’s Ballast Water Management (BWM) Convention, which entered into force in 2017, is affective. Mr Glover explained how IMO resolution MEPC.207(62) and biofouling guidelines produced in 2011 assist in achieving the intent of the AFS and the BWM convention – these being Guidelines for the Control and Management of Ships’ Biofouling to Minimize the Transfer of Invasive Aquatic Species.
“Biofouling is of worldwide concern and there is need for a globally consistent approach to the management of biofouling,” said Mr Glover. “But, MEPC.207(62) is only a guideline.”
MSC invests in hull antifouling robotics
Mediterranean Shipping Co (MSC) will install Jotun’s pioneering Hull Skating Solutions (HSS) on its container ships to reduce hull fouling and fuel costs.
MSC will use high performance SeaQuantum Skate antifouling and HSS on 14,000 TEU MSC Eva later this year.
This solution will proactively work to ensure this vessel’s hull remains clear of biofouling to improve voyage efficiency, reducing fuel costs and significantly lowering CO2 emissions.
HSS will be installed on MSC Eva at GWD Guangzhou Shipyard in China later in 2020, at the same time as it undergoes class renewal and scrubber installation.
Jotun HSS combines antifouling and the robotic proactive cleaner, housed onboard a vessel.
Jotun operators control the HullSkater robot via a 4G connection, conducting cleaning and inspections in line with an individual vessel’s schedule, which is developed through proactive condition monitoring and proprietary algorithm and data analytics.
HullSkater uses magnetic wheels to cling to vessel hulls. It works to remove individual bacteria and biofilm before macro-fouling grows.
Fouling can be removed without risk of damage to, or erosion of, coating. This minimises the need for reactive cleaning, cutting costs, environmental risk and optimising fleet flexibility.