Exploring the impact of sailing parameters on ship hull fouling growth: velocity, idle/dynamic cycles and sunlight exposure

This study investigates the impact of key operational parameters, tangential velocity, idle/dynamic cycling, and sunlight exposure, on biofouling development and coating performance across three commercial marine coatings: an epoxy primer (EP), a copper-based self-polishing coating (AF-Cu), and a silicone-based fouling release coating (FRC). Dynamic immersion tests revealed that AF-Cu performance improved with increasing velocity due to enhanced biocide release, while FRC exhibited optimal performance at moderate speeds, with mechanical damage limiting efficacy at higher speeds. Intermittent exposure profiles demonstrated that longer continuous running phases promote self-cleaning in FRC and stabilize biocide release in AF-Cu, whereas frequent idling reduced coating effectiveness. Shading during idle periods significantly suppressed early-stage algal fouling on EP panels, though barnacle settlement increased later in the season, raising overall fouling ratings due to the disproportionate impact of hard fouling. No shading effect was observed for AF-Cu or FRC. Across all protocols, coating durability and alignment with vessel-specific operational profiles emerged as critical factors in fouling control. These findings emphasize that effective antifouling strategies must integrate both material performance and operational context. The results support the development of more resilient, responsive coatings and encourage operational practices that enhance coating function and longevity under real-world conditions. • Hydrodynamic conditions modulated biofouling settlement on coating surfaces and community structure. • High rotor speeds reduced fouling release coating performance due to mechanical surface degradation. • Extended idle periods in a dynamic cycle governed the balance between fouling growth and removal. • Shading limits early algae fouling, while increasing barnacle settlement at later stages.