To prevent fouling of the hull it is painted with antifouling paint.
In the second half of the 20th century these paints were primarily based on the dispersion of biocides over time. The most known biocide in paints is copper. Copper is toxic to a large number of marine organisms and has been – and still is – widely used in antifouling paints.
Another type of paint from this period is TBT (tributylin) based and this paint is considered highly efficient. During a boom in the use of TBT (tributylin) based paint it was discovered that it had a disastrous effect on marine life. Large concentrations around ports and dry docks affected mammal life in these areas, and in 2001 it was banned by IMO with a stop of manufacturing in 2003 and a stop of presence on ship’s hulls in 2008, Anderson et al. (2003).
Since then other paint types have been developed and the two most commonly used types are selfpolishing and foul release paints, International Paints (2010).