Propeller performance plays an important part in a vessel’s operation. The main causes of propeller deterioration are corrosion, impingement attack, cavitation erosion, and fouling. Corrosion is minimized by constructing propellers of corrosion resistant alloys such as Nikalium and Superston. Impingement attack usually occurs at the leading edge and outer part of the propeller blades. Cavitation erosion is localized damage near the tip and back of the blade. It is dependent on the pressure distribution of the propeller and the wake flow and with modern design techniques, it can be minimized.
Fouling is when marine growth such as algae, tubeworms, and barnacles settle on a submerged surface. Fouling of propellers can cause significant loss of power or speed. Despite this, some ship operators only clean propellers at routine maintenance drydockings. Others carry out regular in-water cleaning and polishing at approximate 6 to 9 month intervals using divers, since they see a noticeable performance improvement after each cleaning.