As a recreational boat owner, I know that barnacles on ship hulls are a real nuisance. But not only are they a pain to remove, the increased water friction will affect that the vessel' performance is negatively: speed goes down and fuel consumption goes up. This issue is particularly costly for large container ships and commercial vessels.

Given my scientific expertise in barnacles, I have been appointed by P+I Clubs to make assessments as to when and where barnacles could have attached to ship hulls — and just as importantly, could not have attached. In doing so, it was possible to identify if this was an Owners' or a Charterers' concern. This depends on how long Charterparties let a vessel stay at port or anchorage. 

For my assessments, I can use photographs from underwater diving survey, provided there is a reference for size such as a draught mark, or scrape samples of the actual barnacles (see photograph and video on the left). These can be send to me from most countries.

I can usually determine the species or genus of the barnacles and this will give me an indication as to how fast they grow. From there it is possible to back-calculate when they first attached. The trading route of the vessel is known from AIS, meaning the two aspects can be matched up to find the likely port of contamination.