Fouling control has long relied on the controlled release of biocides from antifouling coatings; once freed from the antifouling into the seawater layer next to the hull, the biocides poison/deter settling stages of fouling organisms before they settle and adhere to the substrate. By contrast, SigmaGlide works on a physical principle – the low surface free energy and the intrinsic smoothness of the coating make it a surface to which it is very difficult to adhere.

The photograph shows on the left side a normal coated surface (high surface energy)
– the water droplets spread out over the surface and “wet” it.
Such a surface is easily fouled, adhesion of the fouling is tenacious and can be
expensive to remove.

On the right side SigmaGlide-coated surface by contrast, the droplets remain
globular and do not spread; the surface is difficult to wet and fouling will find
difficulty adhering; any macro fouling (e.g. barnacles, tubeworms, “grass”, etc)
that settles when the vessel is stationary are loosely adhered and ‘released’

Surface smoothness and hull roughness

The extremely smooth surfaces that can be generated by the application of SigmaGlide also translate into exceptionally smooth hulls. This can also be seen in the almost mirror-like quality of SigmaGlide coated hulls when application is carried out responsibly. Indeed Average Hull Roughness (AHR) values of around 70 µm have been obtained for well-controlled applications on large ships.