Part-II: Optimum designing of cathodic protection systems of marine platforms

Marine platforms require appropriate protections against corrosion attack for defining their useful life. In part I of this study, rule based analyses were carried out for designing cathodic protection system of a ship. Two reputable rules DNV-RP-B401 and Defstan (NES 704) standards were used for the purpose. Study revealed that rule based analyses do not properly guide on the distribution of anodes over the surface to be protected. Additionally, effects of factors such as quality of harbour water, appropriate application of surface preparation & paint scheme and effectiveness of cathodic protection system are not taken into account. In recent years, numerous software are developed and used for studying corrosion effect and designing cathodic protection for marine going vessels. In this paper (Part II), computational simulation techniques based on boundary element method (BEM) are applied in the studies to evaluate the effect of poor harbour water and material composition changes on the vessel for which; rule based cathodic protection design was performed in part I of the studies. Design optimisation was performed in the commercially available software; BEASY Corrosion and CP. It is concluded that simulation tools that can include factors such as type of material used, quality of harbour water and sacrificial anodes composition in studies can facilitate proficiently in designing optimised cathodic protection system for the design life of any marine vessel vis-à-vis area of operation. In the future work, calculation of number of anodes and their distribution for a ship hull would be calculated by BEM method and design optimization under different environments would be simulated.