There are three reasons antifouling paint should be used:
1) Safety – Heavy fouling growth will reduce the responsiveness of a yacht as well as making it sit lower in the water, due to the extra weight. Fouling can also grow unevenly across the bottom, making the boat off balance, potentially making it uncontrollable. This can have serious implications in challenging weather conditions.
2) To prevent hull damage– Fouling can burrow into hull coatings, opening up the surface and allowing water to come in contact with unprotected metals and fibreglass. This can cause corrosion to metals and blisters in fibreglass through osmosis. These problems are expensive and time consuming to repair.
3) Speed and efficiency – Fouling causes drag, which in turn reduces speed. Therefore, more fuel is needed to drive the boat through the water to maintain the same speed. For racing boats this can make a big difference when competing. An increase in fuel consumption will not only cost more, but will also have an environmental impact due to increased air pollution.