Everyone who has experience in the maintenance of ships or structures is convinced that there is a corrosive action with time, usually in very severe meteorological conditions, especially in the submerged parts of a ship or structure, due to the quantity of paint which, for whatever reason, comes off and which causes a degradation in the protection. You have to consider that part of the surface can be left without paint due to collisions against a quay, a tug, defenses, anchors, etc.
In general, if we want to obtain a good protection, it’s totally necessary to help the paint with other means. Anyway, the best paint can never totally prevent a diffusion of water and oxygen in the areas of the submerged steel, which helps the rusting process.

The best protection against corrosion is a combination of a good paint with a good protection with cathodes, because a good paint is a barrier, which reduces the current that has to be delivered by the cathodic protector. All paints that are used must have a high alkaline resistance because the cathode protection is accompanied by a light alkaline, which must be taken into consideration.