Paint Thickness (too much or too little is not good...)
Repeated hull cleanings
In our opinioin, the only way to ensure an well performing vessel is through condition based monitoring. Proper analysis of data, combined with inspections (and hull cleanings) is the way to ensure good propulsion performance.
The image below show the hull condition of a vessel that has been sailing for four years, and which has already undergone 4 hull cleanings. Our performance system predicted an added resistance of around 40 % compared to Sea Trial performance.