Marine biofouling is the progressive build-up of marine organisms on submerged surfaces, including hulls, thrusters, propellers and other underwater areas on passenger vessels.

Even a seemingly minor layer of slime or biofilm can have a substantial impact on vessel performance by increasing hydrodynamic drag and fuel consumption.​

According to analyses under the GEF–UNDP–IMO GloFouling project, as summarized in the GESAMP report Marine biofouling: non-indigenous species and management across sectors, a biofilm layer only about half a mm thick covering up to 50% of a hull surface can be associated with roughly a 20–25% increase in fuel consumption, while more severe macrofouling can drive fuel use to nearly 50% above that of a clean hull.

These findings highlight the considerable cost-saving potential of proactive biofouling control and underline why effective antifouling and hull maintenance strategies are essential for both operational efficiency and emissions reduction across the maritime sector.

For more information, please refer to https://www.glofouling.imo.org/publications-menu