DNV

Corrosion in water ballast and cargo tanks – DNV observations

The actual corrosion rate in ballast and cargo tanks may differ from the assumptions in the rules and the embedded corrosion models. DNV survey data reveals a significant rise in corrosion findings in water ballast and cargo tanks in oil tankers and bulk carriers at the third renewal survey, with a peak at the fourth renewal (Figure 1). That means that for some vessels, the useful life of the effective coating protection may only be about two-thirds of the requirement of the Performance Standard for Protective Coatings (PSPC).

https://www.dnv.com/news/the-influence-of-temperature-on-the-corrosion-rate-of-cargo-and-water-ballast-tanks/