Non-Lethal Hard Fouling Prevention Shows Promise
Biofouling control is an important part of the effort to reduce the shipping industry's environmental footprint. Fouling reduces fuel economy, raising CO2 emissions per mile and increasing costs for the shipowner. In addition, hull surfaces are one of the main ways that marine invasive species travel around the world (after ballast water).
New improvements in antifouling coatings could help vessel operators to keep down marine growth between drydockings. One of these innovations, the anti-barnacle agent Selektope, has demonstrated fouling prevention performance in testing, including a 40-month trial of an antifouling coating containing the Selektope ingredient on an MR tanker.
The vertical sides of the 45,000 dwt product tanker Team Calypso were coated with a hull coating containing Selektope during its five-year drydocking in 2015. During the last 40 months, owner and operator Team Tankers says that the vessel has been in active operation across a wide range of trade routes, often sailing in biofouling hotspots with water temperatures of up to 90 degrees Fahrenheit. The vessel also spent several extended periods idling in these zones.
However, during the trial, barnacles did not anchor themselves to the tanker’s hull. Selektope activates the barnacle larvae’s octopamine receptor, which keeps them in swimming mode and prevents them from attaching to the hull, non-lethally. A hull inspection conducted at month 35 in the tanker’s in-water-survey schedule established that Team Calypso’s hull was virtually barnacle-free with no soft fouling coverage.
Independent third-party data analysis has also verified the fouling prevention performance of the Selektope-powered hull coating. At month 40, total added resistance on Team Calypso’s hull and propeller due to fouling is very low, at 16 percent, compared to up to 30 percent expected for a reference ship of similar age, size and trading patterns. The development of added resistance was calculated at a rate equivalent to 0.4 percent per month, compared to the expected rate of between 0.5 and 1.5 percent.
Team Tankers Performance & Environmental Manager Capt. Pär Brandholm comments: “Team Calypso has operated for over three years since last dry dock, and we can conclude that the fouling of the hull remains at a very low level and we hope the trend will continue being flat," said Capt. Pär Brandholm, the performance and environmental manager for Team Tankers. The shipowner says that after the successful trial, it is planning to coat the hulls of four more vessels with Selektope-enhanced antifouling.