Performance Comparison of Fouling Control Coatings Based on Time-Dependent Biofouling Model for Ships

Abstract

The selection of the most efficient fouling control coating (FCC) for a new build ship in the design stage is significant for preventing extra fuel consumption and GHG emissions and crucial for preventing unscheduled maintenance operations. Not doing so may cause severe losses in the revenues throughout the operational life of the ship. For this reason, a tailor-made condition assessment in the design stage of the ship should be adopted while considering the ship operational profile and the target FCC performance. Such an approach becomes even more important considering the impact of the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Index (CII), which will come into force in 2023. The study presents the performance comparison of two fouling control coatings based on the time-dependent biofouling growth model. The analyses are conducted through two case studies in which the same ship is coated with two different fouling control coatings and operating at the same ship route and operating profile. The model first predicts the increases in the ship hull roughness in terms of equivalent sand roughness height, and then this prediction is implemented in the CFD based on the wall function approach. Finally, penalties in the frictional resistance and power requirements due to biofouling are calculated every three months duration in a year. The coating performances are compared in terms of increases in power requirements, fuel consumption and GHG emissions. The developed model enables us to select the most efficient FCC among the available FCC’s for the target ship route and operational profile. Maintenance and dry-docking schedules can also be optimised according to the developed model to operate ships in the most cost-effective and environmentally friendly way.