The corrosion behaviors of metallic components from hull structures of an amphibious vehicle in seawater were investigated. Selected steel types and aluminum alloys were subjected to accelerated corrosion tests in artificial seawater to collect data for simulation of cathodic protection with sacrificial anodes. The electrochemical data obtained via potentiostatic tests were used to simulate cathodic protection of the metallic components under seawater. Potential distributions in marine environment were evaluated to design the cathodic protection system that could impress the currents. Random paint deficient areas on a steel and aluminum components were created to test the protection performance of sacrificial anodes on the damaged surfaces.