The Economics Of A Long Term Coating

An important challenge during ship construction is the protection against corrosion of the ballast tanks. These tanks have many compartments, contain multiple structural elements and play a critical role in the seaworthiness. The majority of the ballast tanks are prepared and coated according to IMO Performance Standard for Protective Coating regulations (PSPC), using a light colored epoxy coating that, when maintenance is being performed by the crew, must remain in a "good" condition for 15 years. This method is set next to a protection system applied by a given owner who keeps its ships in an excellent condition for their complete lifetime using a long term coating. More attention is paid to the preparation and application of the coating and consequently it protects the ballast tanks for more than 25 years. These coating strategies are compared in an economic analysis, supplemented with a sensitivity analysis to evaluate the outcomes due to variable parameters. The results indicate that a long term coating only pays off for owners willing to keep the ballast tanks of their vessels in a good condition for the complete lifetime. The decisive factor is that a long term coating entails no recoating in dry dock. The latter results in less toxic components in the atmosphere.