Shell shock

Regarding the huge goose barnacle growth on some the Golden Globe Race yachts, goose barnacles are well known to be found on floating debris, so if the boats are moving slowly or not at all for any period, that could allow settling.

Once the juvenile barnacles reach a certain point in their life, they have to settle. This means that the usual cues that the larvae would pick up from the antifouling (ie this is toxic, so I won’t settle here) can be overridden and they settle anyway. The paint on the boat may or may not be strong enough to kill them.

It looks like some of them could have settled on damaged paint, so this is enough to let one attach and then many others to the one that attached. We see this in our panel tests for normal barnacles and other species. A pinhole or small spot damage can be enough to let some settle, which then lets others in to overcoat the fouling.

Once you get conditioning of the paint with other fouling types (slime, weed etc) this can aid the settlement of the barnacle. This damage could be why we saw the increased attachment.

Where the settlement has occurred may be in a high flow rate area of the boat. It may be that the coating has polished through or developed a thick enough leach layer to dilute the biocide concentration at the surface, allowing settlement. If the coating is a fast polishing system, then this would explain why they are seeing issues at the rear.

Thomas Olsen Marketing director, Hempel