Evaluation of in-service speed performance improvement by means of FDR-AF (frictional drag reducing anti-fouling) marine coating based on ISO19030 standard

Abstract

In previous reports by the authors, the drag reduction performance of a novel frictional drag reduction self-polishing copolymer (FDR-SPC) was presented. The drag-reducing functional compound polyethylene glycol methacrylate (PEGMA) was used in the synthesis process, thereby allowing the release of polyethylene glycol (PEG) into seawater by a hydrolysis reaction. In a laboratory skin friction measurement, a low-friction antifouling (AF) coating based on FDR-SPC was found to provide a 25% skin friction reduction compared with a conventional AF coating. This coating was then applied to the entire underwater surface of a 176 k DWT bulk carrier during dry docking in December 2015. The propulsion performance of the present vessel as well as the weather conditions were recorded over five years from November 2014 to December 2019. It was imperative that the hull coating performance be evaluated without being affected by the additional resistance component associated with weather conditions such as wind and waves. ISO 19,030 is proposed as a new international standard for that purpose. Based on this standard, in-service navigation data collected from the 176 k DWT bulk carrier, which amounts to 5.7 million data points, are analyzed to assess the speed improvement performance of the present frictional drag reduction antifouling (FDR-AF) coating. The analysis results indicate that the present coating leads to a speed increase of 3.72% over the conventional AF coating. The speed improvement effect is equivalent to power (fuel) saving of 11.7%.