Investigating the Impact of In-Water Cleaning on Coating Performance and Cleaning Efficiency Using a Lab-Scale System

Marine biofouling, characterized by the settlement of microorganisms, algae and marine organisms on submerged structures, presents large challenges to the maritime industry and oceanic environments [1]. Increased hydrodynamic resistance on vessels arising from biofouling leads to greater fuel usage, increased greenhouse gas emissions, and diminished functional effectiveness [2]. Biofouling, furthermore, possesses a large role in the distribution of non-indigenous species, which disrupts native aquatic ecosystems and also biological diversity [3]. Maintaining a ship's hull free from biofouling is important for alleviating such detriments, and underwater cleaning is emerging as a key approach for limiting the accumulation without the necessity of routine dry-docking [4], [5]. By means of buildup elimination as a vessel proceeds in service, in-water cleaning improves ship efficacy, lengthens the serviceable duration of fouling control coatings and reduces ecological repercussions. Nevertheless, the correlation between diverse cleaning processes and coating types affects both the degree of fouling removal and the durability of protective layer.

The effectiveness of underwater brush cleaning was evaluated using a laboratory-scale cleaning system [6]. Laboratory testing provides a controlled environment for the systematic evaluation of underwater cleaning and its effect on coatings. This artificial setup allows for an accurate and comprehensive evaluation of both cleaning efficiency and coating durability. To replicate realistic fouling conditions, samples were exposed to the natural sea environment on an exposure platform in the Baltic Sea. In addition to the cleaning device, different brush types with different geometries and bristle stiffness were designed and tested to investigate their effects on different fouling control coatings. This study allowed for a systematic analysis of how brush geometry and cleaning parameters - such as force applied - affect the efficiency of biofouling removal from different surfaces. In addition to cleaning efficiency, the effect of brush cleaning on coating integrity was also investigated. The results were correlated with the mechanical properties of the coatings. This comprehensive approach provides valuable insights for optimizing underwater cleaning strategies to improve biofouling management while ensuring coating longevity.