In recent years, experimental investigations have been performed on the drag effect of anti-fouling coatings at the University of Newcastle in partnership with International Paint Ltd. In particular, the effect of surface roughness on the skin friction of flat surfaces was investigated in the university's cavitation tunnel, and the effect of biofilm (slime) was tested in a flow cell. This research allowed a step change in the understanding of the effect of different surface finishes on skin friction. However, limitations due to the experimental nature of the tests led to some critical research questions remaining unanswered. The aim of the project is to gather new knowledge on the effect of coating properties, in particular the effect of surface roughness on ship resistance, power and fuel consumption in real sailing conditions.