Analisis Perbandingan Efektivitas Cat SPC Berbasis DCOIT dengan Cat Anti Fouling Komersial terhadap Pertumbuhan Biofouling

Abstract

Biofouling is the attachment and growth of marine organisms on submerged surfaces, which can reduce the performance of marine structures and accelerate material degradation. This study compared a DCOIT-based self-polishing copolymer coating (JMO) with a commercial Jotun antifouling coating containing copper pyrithione (CuPT) as a booster biocide (JJ). ASTM A36 steel plates coated with JJ and JMO, together with uncoated control plates, were immersed for 12 weeks in Ketapang waters, Banyuwangi. Biofouling development was evaluated through weekly specimen weight measurements, Fouling Resistance (FR), image analysis using ilastik and ImageJ, and nonparametric statistical tests. The control showed the greatest weight increase, while JJ- and JMO-coated specimens remained relatively stable. At week 12, the FR values were 65 for JJ, 83 for JMO, and 85.7 for the control; however, the control obtained an overall performance score of 0 because of severe corrosion. The Kruskal–Wallis test showed significant differences among treatments (H = 75.574; df = 2; p < 0.001). The Mann–Whitney U test also indicated a significant difference between JJ and JMO (U = 357; Z = −3.281; p = 0.001). JMO had a higher mean rank (44.58) than JJ (28.42), indicating greater total surface coverage. Nevertheless, fouling on JMO was predominantly thin cyanobacterial microfouling, whereas JJ developed macroalgae by week 12. Therefore, although JJ exhibited lower total fouling coverage, JMO produced a less prominent fouling profile that may cause a lower hydrodynamic penalty during the 12-week immersion period