Biofouling poses significant challenges for the maritime industry and is a threat to the environment. When the smooth underbelly of a ship becomes encrusted with aquatic organisms, frictional drag increases, reducing efficiency, and leading to the use of more fuel and to higher emissions. The stowaway creatures have also been shown to be a main contributor to the spread of invasive marine species, many of which have the potential to devastate ecosystems and drive local species into extinction. A study in New Zealand found that more than 70% of aquatic invasive species originated from biofouling on ship hulls.
While paint manufacturers serving the marine sector have developed low surface energy coatings and other solutions that effectively reduce biofouling, no definitive solution has been available to completely prevent biofouling. Even with the highest-
performing coatings, ships facing the greatest biofouling challenges still require periodic reactive cleaning. Unfortunately, a lack of standardization with such cleaning procedures leads to a variance in quality from location to location and operator to operator, according to Geir Axel Oftedahl, business development director at Jotun. “Some procedures can severely damage coatings and assets, with practices involving outdated equipment such as hard brushes,” he observes. Some are also potentially very damaging to the environment, with the dislodged lifeforms simply drifting down to set up a new home in a new ecosystem, Oftedahl adds.
With a conviction that biofouling poses a great enough burden on industry and on the planet that a solution—better yet, a prevention—would be embraced, Jotun set out to develop a solution. The result is a remotely operated robot called the HullSkater, designed to be effective and safe for Jotun’s SeaQuantum Skate coating.
“Imagine a robotic lawnmower, only one that’s very good at diving,” quips Oftedahl. It is a good description of the HullSkater, which roams a vessel on magnetic wheels while being operated via a 4G connection from a dedicated, around-the-clock control center in Norway. When not in use, the HullSkater is stored in a custom on-deck housing. Equipped with high-definition cameras and sensors, the HullSkater monitors potential biofouling, collects data, and can be used to clean hulls to a standardized level using built-in brushes. The entire process, according to Oftedahl, takes between two and eight hours depending on the size and condition of the vessel.
The monitoring process goes beyond a simple visual evaluation to use a proprietary Jotun fouling prediction algorithm. It predicts levels of fouling and customizes service levels for each individual owner and vessel, according to Tom H. Evensen, sales director for hull performance solutions with Jotun. The algorithm is based on data collected since 2011 through the Jotun hull performance solutions program, which includes installation of sensors to enable performance monitoring based on standardized principles (ISO 19030) for the measurement of changes in hull and propeller performance. The comprehensive data set includes data on hull performance from many types of vessels on different trade routes. “With this technology, we can catch biofouling at a very early stage—when there is just slime or a minor biofilm present—and thus ensure ‘always clean hulls’ with minimal speed loss,” he asserts.
Overall, the Jotun Hull Skating Solution (HSS) consists of five solution components: the high-performance antifouling coating SeaQuantum Skate, proactive condition monitoring, inspection and proactive cleaning with the underwater robotic Jotun HullSkater, high-end technical service, and performance and service level guarantees. Jotun piloted and vessel-tested the HSS for more than two years. It is ideally suited for vessels facing the greatest biofouling challenges, according to Evensen.
Wallenius Wilhelmsen Ocean, the operator of a fleet of 126 roll-on roll-off (RoRo) vessels, 11 marine terminals, and 71 processing centers around the world and a pioneer in seeking new ways to reduce the environmental impact of its operations, tested the system as part of its holistic approach to reducing emissions. According to Geir Fagerheim, the company’s senior vice president of marine operation, this holistic approach already included everything from weather routing to engine optimization and hull coatings to sophisticated hydrodynamic hull, rudder, and propeller designs. “While achieving zero emission vessels will not be easy, we recognize that by taking a collaborative approach to common challenges, we can accelerate the development of technologies that can make a difference,” says Fagerheim. “Jotun Hull Skating Solutions certainly fits that description.”
In 2017, Wallenius Wilhelmsen Ocean gave the HSS team access to the Talisman, a DWT 38500 RoRo carrier built in 2000. The HSS project team applied antifouling test patches on the hull, installed the unit on board, and provided training for crew members on maintenance, deployment, retrieval, and storage of the unit. The multi-year pilot test with Wallenius Wilhelmsen Ocean (and other owners, including Berge Bulk and Maersk) provided the project team with valuable insight on what worked—and what did not, according to Oftedahl. “In addition to providing us the opportunity to test the unit under different operational conditions, Wallenius Wilhelmsen was also instrumental in helping us reach out to port authorities to ensure we could operate in compliance with local regulations,” he adds.
Over the past two years, HSS has been successfully pilot-tested on vessels in different ports around the world. Today, Jotun is working to establish agreements with some ports that require documentation of a clean underwater hull prior to port call. “Because HSS is a new technology, no uniform standards currently exist,” explains Oftedahl. “Our relationship with our pilot partners has been enormously helpful in working through these issues.”
Indeed, by being proactive and working in collaboration with suppliers, Fagerheim believes the industry can achieve better results, from reducing bunker costs to meeting increasingly strict demands of cargo owners and complying with regulations on emissions and alien invasive species, faster. “As we have seen with Jotun Hull Skating Solutions, a project that involved a broad range of stakeholders, collaboration can produce some game-changing technologies that get us one step closer to a more environmentally responsible industry,” he states.
Oftedahl adds that, despite the excellent coatings currently available, owners facing the most challenging operations still need a new solution for optimal hull performance. “With the performance levels we can offer—the efficiency, economy and environmental standards HSS is capable of delivering—this is more than an operational matter, it’s a business-critical decision,” he asserts.
Concludes Evensen: “If all vessels in our targeted segments converted to HSS, it would result in a CO2 emissions reduction of at least 40 million tons per year, not to mention huge benefits in terms of operational expenditures. That is an incredibly powerful proposition.”
To view a video of the Hull Skater in action, interact with a 3D model of the Hull Skater, and access instructions to build a Lego version of the Hull Skater, visit https://jointherevhullution.com/.
CoatingsTech | Vol. 17, No. 9 | September 2020