Fouling of hulls is a problem for all boat owners, and one of the most difficult organisms to deal with is barnacles. A research group at Sweden's University of Gothenburg Department of Cell and Molecular Biology has published in the scientific journal Biofouling that it is possible to mix into coating molecules an agent which the adult barnacles cannot grow.
“When newly matured adult barnacles attempt to penetrate through the coating in order to establish a fixed location to grow, they are extremely sensitive to certain molecules known as ‘macrocyclic lactones,’ which are normally produced by certain bacteria,” says Professor Hans-Björne Elwing.
When such molecules are mixed into the anti-fouling coating, the treated surface is first colonised by barnacles in the normal way. But as soon as the young barnacles have matured into adults and attempt to establish stronger contact with the surface, they lose contact and probably die. It is also the case that certain brown algae counteract the colonisation by barnacles on the surfaces of leaves in a similar manner.
“Using this discovery, we have managed to create coatings with new binding agents that shut down the release of the macrocyclic lactones into the marine environment. Further, only trace amounts of the macrocyclic lactones are required in the coating to give full effect against barnacles.”
The research group has shown through field trials on leisure craft that the addition of macrocyclic lactones can fully replace copper in coatings used on such craft, on both the eastern and the western coasts of Sweden, and for several seasons.