HullWiper | No More Foul Play: Time to Tackle Biofouling

No More Foul Play: Time to Tackle Biofouling

19 Aug 2020

Hullwiper in action

As regulatory pressures associated with hull biofouling mount, could recent advances in marine robotics pose the solution?

Some problems are too big for one industry alone to solve. They require sector collaboration and the cross-pollination of fresh ideas. Vessel biofouling—the undesirable accumulation of plants, algae and microorganisms on a ship’s hull—is one such dilemma and an issue that, owing to the planned tightening of maritime regulations, demands immediate action.


Biofouling benefits no one, other than invasive aquatic species, perhaps. When vessels travel in and out of international waters, from one port to another, they provide perfect passage for these nomad biofoulers, and inadvertently spread intrusive foreign species to other parts of the world. Besides this mounting biothreat to our planet’s marine ecosystems, there are the escalating costs of at-sea inefficiencies to contemplate: Colonized hulls cause exponential friction which, according to the Office of Naval Research, can cause up to 60 percent more hydrodynamic drag; the more drag, the higher the fuel consumption and, of course, the corresponding CO2 emissions.

The numbers are staggering: The International Maritime Organization (IMO) suggests that clean, smooth hulls and propellers can equate to fuel savings of as much as 10 percent, a figure supported by U.S. Navy studies that cite biofouling as a “chronic and costly problem,” while the Clean Shipping Coalition estimates that biofouling on hulls cost the shipping industry as much as $30 billion per year.


Biofouling rates are influenced by a number of factors—from naval architecture to coating systems to waters navigated—so accumulation patterns vary. This makes monitoring this out-of-sight enemy tricky, but imperative. The first stage, exacerbated by warmer port waters, is the attachment of biofilm, a process that begins within hours of hull submersion. This initial layer can be removed without excessive force but as it accumulates it becomes increasingly difficult to detach without causing damage to expensive—and often toxic—hull coatings. In other words, the timing of biofouling inspection and subsequent intervention is critical to both hull performance and integrity.

There are decreed international standards, certainly; ISO 19030-1:2016 outlines general principles for the measurement of changes in hull and propeller performance and defines a set of KPIs to help vessel operators determine an appropriate schedule for hull husbandry. But this essentially involves correlating elementary navigational variables between two set time periods, as opposed to anything remotely resembling dynamic data analytics.

However, GreenSteam, a software company backed by BP/Castrol, advocates a smarter approach to condition-based monitoring, powered by machine learning. GreenSteam has developed a number of platforms to empower ship operators to better manage their carbon footprint, including the Fouling Analyzer, which, in addition to historical data, leverages machine learning software and real-time data to provide accurate insights and actionable advice regarding cleaning schedules, as well as the performance of active hull coatings.

Similarly, Propulsion Dynamics, out of Denmark, use theoretical and empirical algorithms to analyze the influence of hull and propeller biofouling through their CASPER—Computerized Analysis of Ship Performance—platform. By using a Digital Twin hydrodynamic model, the company’s naval architects analyze vessel data and generate a daily report that provides precise calculations of speed, fuel consumption and resistance and, most importantly, accurate estimations on the fuel penalty caused by hull and propeller fouling.


Clearly, a clean smooth hull is a win-win situation for industry and environment and, irrespective of other antifouling measures, at some point cleaning is inevitable. For years, commercial divers have played an indispensable role in this process, from in-port assessment to hacking away at stubborn barnacles. Diligent divers can be a cost-effective way of recalibrating a hull’s hydrodynamics, but forceful cleaning can result in significant coating damage, the release of toxic bottom paint, inevitably leading to a period of costly drydocking. While vessel operators cannot avoid drydocking forever, however, the interval between drydocks can be extended and the scope of restorative work will often depend on how assiduously the hull has been monitored and maintained.

In recent decades, advances in mechanical engineering have ushered in a more tech assisted approach to hull cleaning. Not so much man versus machine, but rather a case of using breakthrough technologies to enhance a service. Subsea Global Solutions, a long-established provider of underwater repair and maintenance services, promotes a diver operated approach to incorporating subsea technology and has developed a number of ride-on cleaning systems—including the Whale Shark—to help vessel owners “manage their coating.” Similarly, Piccard Divers has also developed their own equipment, which includes the BRUSH-KART, which allows divers to clean up to 3,600 m2 per hour, depending on the degree of fouling.

Of late, however, there has been growing interest in developing marine robotics— unmanned systems—to provide proactive “hull grooming” services, specifically designed to remove fouling at the biofilm level. In time, these systems may help reduce the volume of commercial divers needed in port waters—a notoriously dangerous occupation—and instead give rise to a new breed of ROV operators and expert hull inspectors.

So far in 2020, we have seen a number of high-profile contract announcements and product launches in this space. Greensea, for example, has begun marketing a man-portable robotic Crawler that is controlled via a proprietary hull-relative navigation system and is paired with a VideoRay MSS Defender ROV, allowing it to fly between areas of interest, reattach in seconds, and efficiently perform inspection and intervention tasks with a degree of precision not possible with a smaller free-flying ROV.

“Providing a stable base platform for a camera, laser imaging scanner, or manipulator will greatly enhance accuracy, and ultimately safety, by enabling small robotic systems to perform work previously requiring a diver,” according to Karl Lander, Greensea Program Manager.

Jotun also made a splash earlier this year with the launch of the company’s Hull Skating Solutions, with the HullSkater ROV as lead protagonist. The Norwegian manufacturer of protective marine coatings has partnered with Kongsberg to champion a “revhullution,” a service that offers “high-performance antifouling, proactive condition monitoring, and inspection and proactive cleaning.” The HullSkater attaches to a hull with its magnetic wheels, each equipped with electric motors for propulsion and steering, and uses its cameras and sensors to help navigate and document the fouling, before removing it with its motorized brush. An umbilical connects the ROV to the control center and 4G coverage enables remote operations from anywhere in the world. The HullSkater is the culmination of years of testing at selected ports around the world.

SeaRobotics is another organization that has been busy in the field, testing their SRHullBUG system, which, like the HullSkater, favors brushes—nine in total—for its grooming tool. But the real gamechanger, according to company president Don Darling, is the system’s unique capture and filtration system which “reduces fouling to the micron level and allows us to remove particulate and heavy metals from the water.” This distinction is particularly pertinent amid the surging environmental pressures—cleaner hulls impede cleaner seas if the offending effluents are simply pumped back into the water. The SR-HullBUG has already proven effective in the cruise line industry, but clearly there are broader applications for a sophisticated filter system among the ocean industries.

As opposed to brushes, HullWiper uses adjustable high-pressure seawater jets to avoid, the company maintains, the use of abrasive scrubbing or harsh chemicals. Whether waterjets are more effective than brushes at removing microorganisms remains unclear—and certainly warrants further insitute research—but, in general, they require greater power sources. The captured residues are then pumped through a filter unit and into dedicated drums onshore. The Hullwiper service has proven popular and the company has established operational bases in Panama, Australia, Spain, Mauritius, as well as various ports serving the Middle East. With plans to expand operations to the Asian Subcontinent and the Far East, the appetite for ROVdeployed solutions is undeniable.


In 2018, the IMO’s Marine Environmental Protection Committee (MEPC) laid out some ambitious—but motivating—goals to reduce global CO2 emissions, headlined by the target of reducing GHG contributions “by at least 50% by 2050 compared to 2008, while, at the same time, pursuing efforts towards phasing them out entirely.” This was followed, in June 2020, with the launch of the Global Industry Alliance (GIA) for Marine Biodiversity, an initiative managed by GloFouling Partnerships, a five-year (2019-2023) global IMO project on biofouling mitigation. The GIA intends to work with private companies from a range of industries beyond shipping—including aquaculture, offshore oil & gas, offshore renewable energy—and provide a forum for collaborative steps to tackle two key environmental issues: protecting marine biodiversity and reducing greenhouse gas emissions.

The GIA will leverage the influence of key partners such as the World Ocean Council (WOC), the project’s lead for engaging the ocean business community, to foster and facilitate investment in time-critical solutions to biofouling. IMO Secretary-General Kitack Lim said, “Under this new initiative, these industry champions, from different sectors, are coming together to address common challenges and move towards a more sustainable use of ocean resources.”

Concerted efforts of this magnitude require more than just governance; they require cooperation, collaboration, and, indeed, compliance. Success, out on the high seas, will be contingent on shipowners documenting their hull management measures, while ports will demand increasing transparency on hull conditions and, as has been the case in New Zealand, be ever more likely to expel vessels failing to act accordingly.


The challenge, then, will be to establish a specific set of hull-cleaning standards by which any of the 80,000 globe-circulating merchant ships, and any other vessel for that matter, can self-police any “foul” play. BIMCO, the world’s largest shipping association, is the driving force behind efforts to define such gold standard criteria, which they aim to have sanctioned by the IMO. This similarly requires multi-tiered stakeholder management, but first and foremost the alliance of vessel owners, paint manufacturers and the hull cleaning supply chain. As drafts are refined, the next step will be to apply practical tests to establish an approval standard that outlines the minimum requirements for in-water cleaners based on thorough water testing verified by accredited laboratories. How long this process will take is unclear, perhaps 2 – 3 years, but evidently this is a critical moment for the marine technologies looking to be part of the solution.

However, even as attitudes shift towards proactive hull grooming, questions remain. The enormity of the problem can be daunting, the scale of which overshadows any one industry. Advances in coatings could prove pivotal, especially if we see a movement for more non-biocidal formulas; or perhaps materials will be defined by the technologies developed to clean them; Jotun’s Hull Skater Solutions would certainly hint to a trend for synergistic R&D.

Busier shipping lanes only intensify the current biofouling predicament but in 2020, paradoxically, amid the COVID-19 pandemic, slumps in international trade have resulted in widespread cargo ship redundancy; oil tankers have become floating reserves; and the cruise industry has proverbially run aground. This period of relative inactivity may have helped momentarily offset CO2 emissions but, somewhat mercilessly, vessels lying at anchor—especially in port—are prone to accelerated rates of biofouling. In short, our loss of productivity is inversely proportional to the gains of our adversary. The time to act is now.

Source: ON&T