The most effective polymer-based coating or paint for preventing corrosion on metal surfaces in a marine environment is an epoxy-based coating. Epoxy coatings are known for their excellent adhesion, chemical resistance, and durability. They form a strong bond with the metal surface, providing a barrier against water, salt, and other corrosive elements found in marine environments.Epoxy coatings can be further enhanced by incorporating anti-corrosive pigments, such as zinc phosphate, which provide additional protection against corrosion. Additionally, using a multi-layer coating system, including a primer, intermediate coat, and topcoat, can further improve the performance of the epoxy coating.In summary, an epoxy-based coating system with anti-corrosive pigments and a multi-layer application is the most effective polymer-based coating or paint for preventing corrosion on metal surfaces in a marine environment.