I am looking for typical paint and primer thicknesses on the hulls of
commercial ships (cargo vessels, oil tankers, RORO, bulkers etc, not
navy vessels or sailboats). I am not interestested in anything above
the railing. Marine paint manufacturers have recommended thicknesses
(I am interested in this info) but what the industry does in the real
world is more important to me. For example, sometimes, hulls are
sandblasted to rough up the old paint before  application of the final
coat instead of the more expensive method of blasting down to the bare
metal and priming and painting. If you can find IMO regulations on
this, that would be swell.