Anticorrosion protection systems - Improvements and continued problems
Paper in proceedings, 2009
The paper is about anticorrosion protection systems for steel ships, in particular tankers and bulk carriers. The New IMO Performance Standard for Water Ballast Tank Coatings are based on the INTERTANKO recommendations for coatings lasting up to 15 years in ballast tanks. This new standard was discussed during a workshop at Chalmers University of Technology in May 2008 and was seen by participants as already being below the state of the practice of most European ship owner's requirements, not at least regarding the qualifications and experience of the coating inspectors. The new standards require one inspector with integrity and clear responsibly. It is well known that coating layers, which are too thick, may crack due to the residual stresses of the coating itself. An effort to quantify the ageing of coatings due to humidity and heat has been made in the project SAFECOAT, where test specimens after ageing were cyclically loaded. There exist field observations of cracking due to the combination of ageing of coating and local high strain due to repeated load-cycles from full load to ballast. Test results from the project SAFECOAT was discussed and related to the praxis of stripe coating around edges. The paper gives overview of the new regulations and the experience and concludes with advice for further research.