Cathodic Protection of Ship Hulls by Galvanic Anodes. Design Evaluation

There is long experience with galvanic cathodic protection of ship hulls but in the recent past there has been a need for cutting down repair costs. In order to improve the corrosion protection design and to extent ship’s life great attention has been paid to modeling and understanding electrochemistry-current distribution.

From a practical point of view, the best way to retrofit the design criteria would be to check the galvanic anodes real consumption during replacement operations when ships are dry docking at shipyard for the biannual hull inspection; unfortunately, this is not a standard procedure. In order to decrease dry dock stay costs, anodes are cut and put away soon after the ship has been cleaned and inspected for repair.            The aim of the present paper is to assess the cathodic protection system performance of several ships in order to improve the design.  Individual consumption, corrosion potential and efficiency of the anodes were evaluated.

A new design has been proposed based on the results obtained.