In-water hull cleaning under the spotlight at PortPIC 

With hull fouling accounting for a 7%-10% increase in fuel consumption, and therefore emissions, solving the problem goes a long way towards reducing emissions without a need for levies.  

The many speakers and panel discussions at PortPIC addressed various aspects of antifouling measures and in-water cleaning of hulls, including regulations and compliance, as well as technical developments and practical implementation of robotic cleaning systems and other solutions. 

At a time when interest in the impacts of biofouling on efficiency and biodiversity is surging, IMO has recently updated its guidelines on the subject with mandatory regulations being widely predicted for the near future.  

This is likely to add pressure on owners, building on the regulatory action against ships with fouled hulls already taken by several states including New Zealand and Australia, with Norway planning to join them in 2028.  

At least the need for international standards connected to new regulation has been recognised in advance, as there are two ISO standards relating to in-water cleaning (IWC). ISO 20679:2025 covers testing IWC systems and the soon to be published ISO 6319 outlines how to conduct and document IWC cleaning operations.  

“As regulations tighten and industry moves toward a global framework, the need for strategic biofouling management has never been greater. Ensuring that the industry is aware of and understands the solutions and technologies is important, also in terms of how they can help the industry decarbonise, protect diversity, and optimise fuel efficiency,” said Jotun regulatory affairs manager Petter Korslund. He also highlighted how the Biofouling Guidelines and IWC guidance issued by IMO stress the importance of a management strategy centred around prevention, monitoring and timely interventions in building a sustainable path. 

Mr Korslund also made a presentation based around Jotun’s recent survey report on biofouling. The study, based upon a survey of 1,000 shipowners, highlighted that around 40% of shipowners have experienced regulatory penalties due to biofouling-related issues, and a similar number were denied port access due to non-compliance issues related to biofouling. “Today, half of those surveyed told us they avoid ports with stringent biofouling regulations, a strategy that becomes increasingly unsustainable as global standards continue to tighten,” said Mr Korslund.  

Also commenting on the study, Jotun global category director, hull performance, Morten Sten Johansen said the survey results are a “stark reminder of the cost of being unprepared”. 

Bellona Foundation senior advisor, maritime, Irene Øvstebø Tvedten gave a presentation titled, How Far Are We from an Internationally Harmonised Regulatory Framework for Biofouling Management? “At Bellona, we are encouraged by the ongoing developments in biofouling management. New coatings, in-water cleaning systems, and other promising technologies are continually being tested, analysed, and refined.”  

“However, time is ticking,” she warned and highlighted the move towards mandatory regulation. As well as the new ISO standards and the IMO guidelines, she pointed out that at MEPC 83 in April, IMO member states agreed to develop a legally binding framework for the control and management of ships’ biofouling. She also emphasised the need for a science-based, efficient process. 

Another paper, by Ballastwater & Environmental Manufacturers’ Association (BEMA) technical director Mark Riggio, also explored this theme and covered how BEMA has launched a global biofouling research and data development initiative designed to support evidence-based policy formation.  

Balancing hull performance with environmental responsibility, and how cleaning methods avoid harming coatings or water quality, were also discussed at the conference.  

Compatibility of coatings and cleaning systems explored 

Practical considerations around the compatibility of in-water cleaning systems and coatings was explored in a presentation by Jotun fouling protection R&D senior chemist Anita Børve. It is clear that a cleaning system that damages coatings is not a good thing, and indeed this matter is also addressed in the new IMO guidance and in ISO 20679. 

The IMO guidance said, “The compatibility should be determined and documented based on testing at specified fouling ratings”. This is important, as a system that works fine on slime or micro-fouling may cause damage to the coating if used on macro-fouling. The ISO 20679 standard requires that observations on the physical condition of coatings should be recorded and reported using photos or videos. Observation would cover visible damage such as scratches, bare metal, pitting and paint flaking among others and suggested measuring dry film thickness as an optional alternative. 

Jotun’s research paper reported on the proven compatibility of Jotun’s HullSkater and its SeaQuantum Skate coating and covered the testing around water quality before and after cleaning on several in-service vessels. These tests showed there were elevated levels of metals, organics and particulates when incompatible coatings and coatings in poor condition were cleaned. Jotun concluded that while water testing can confirm compatibility or otherwise, it cannot quantify the degree of incompatibility.   

Perspectives from ports and shipowners 

A port authority perspective on in-water cleaning was given in a paper presented by Port of Bergen head of QHSE and sustainability, Jørn-Erik Hausmann. Along with the port of Oslo, Bergen has implemented a ban on in-water cleaning unless the equipment used is pre-approved and captures all debris produced during cleaning.  

The paper covered a pilot project began this year which is aimed at refining the procedure into a practical method both ex-situ and in-situ testing. This should align with draft requirements issued by the Maritime Authority in Norway for all ships entering Norwegian waters, as well as for all vessels conducting in-water cleaning activities within Norwegian territorial waters. 

The question of whether to only approve in-water cleaning systems that employ capture is one that has sparked debate. As acknowledged in the paper, IMO has recognised that there is not yet sufficient scientific evidence and global consensus to set discharge standards for waste substances based on specific concentrations. A complete capture and/or no impact on the coating is not technologically achievable. IMO has therefore adopted a statistical approach whereby concentrations of each substance near the cleaning unit and in any cleaning system effluent should not be significantly increased relative to ambient levels. 

The port of Bergen is allowing cleaning equipment without capture to be used if the coating does not release waste substances during cleaning and if it can be justified that equipment will not clean any area that contains macrofouling or non-native organisms. 

Whatever regulations are eventually formulated, it will be down to operators to best decide how to comply with them. A paper presented by Jean-Loup Barrere of French ship operator CMA CGM described the shipowners’ perspective. The paper looked at the history of hull fouling and methods to combat it and the practical issues around in-water hull cleaning.

CMA CGM is of the opinion that proactive cleaning that prevents biofouling from gaining a foothold is the best option as it eliminates the biodiversity threat and ensures an efficient ship that will use less fuel and hence lower emissions. The paper also looked at some of the problems with cleaning in ports, pointing out that the side of the ship against the wharf is inaccessible to cleaning systems, that ensuring any system that is carried onboard is approved by all ports likely to be visited. Jean-Loup Barrere also commented, “the best solution would be a proactive cleaning system which would work fully autonomously during transit, but no such system is currently available on the market.”

The papers presented at PortPIC and developments in the industry demonstrate that it is reasonable to assume that because biofouling has such a direct impact on bottom line financial figures, the shipping industry will be less hostile towards regulation than it has been towards some other issues in the past. Also, using robots carried on board or accessible at strategic locations will make proactive cleaning easier and cheaper than in the past. That is a win-win situation, operators benefit from lower fuel bills and less levies, and the environmental benefits by eliminating species transfer at the same time. 

Progress made but much more to be done 

PortPIC concluded with a forum discussion where the consensus was that “the good mix of different perspectives and expertise discussed in an open, and solution-oriented manner made this arguably the best PortPIC ever” said the forum moderators Mr Bertram and Mr Korslund. 

The forum reflected that robots are coming, but only gradually, and best practice is often still hybrid with a mix of divers, robots and ROVs. Still, great progress in inspection in the last decade was widely seen with the price of drones falling, which now offer rising capabilities. 

And the participants agreed the industry is marching towards and preparing for mandatory in-water cleaning, but the “devil is often in the detail” and while there are guidelines and standards, there is a need for detailed interpretations and instructions on how to do the real-world processes. For example, what is ‘effective’ cleaning and how do you measure it reliably and fairly? 

Also, views were expressed that compatibility between coating and cleaning process and materials is being anchored in the minds and standards, and that there is significant progress in awareness in the industry. However, proactive cleaning, commonly known as grooming, is still more of a vision than reality even for large and renowned shipping companies.  

On a more positive note, knowledge on best practices for in-water cleaning is increasing, but implementation in industry practice is a thorny and slow process, not least because of diverging financial interests between stakeholders such as time charterers and shipowners. Also, the forum voiced the opinion that IMO should oblige Port States to allow regulated in-port cleaning, but this endeavour is likely to face resistance from some states.  

“Clearly, different stakeholders will have different interests, and they may have varying opinions in terms of the solutions. But at the end of the day, we’re all moving in the right direction because we all acknowledge there’s no ‘silver bullet’ to solving the global biofouling problem and there’s a need for more collaboration and innovation,” said Mr Johansen and concluded, “To this end, PortPIC is a vital platform  and  we remain committed to adding value to the biofouling debate, and making continued progress towards clean, sustainable shipping.”