Zoom Mtg. No. 7 – Experiences with Anti-Fouling Treatments

This meeting will provide an opportunity to exchange experiences with antifouling paints and possibly other ways to inhibit underwater fouling. At a recent Zoom meeting several of those present indicated that they would be happy to contribute to this so if you can tell us about your experience, good, bad or indifferent, with a particular antifouling treatment in a particular geographical area please do tell us about it.
As an introduction to this meeting, there appear to be five main types of antifouling treatment as follows:

1. Soft Antifouling paint, also known as eroding or ablative – the whole thickness of a biocide impregnated paint coating slowly erodes. This reduces the need to remove old paint before applying new. This is the most widely used kind of antifouling paint today.
2. Hard Antifouling paint – biocides dissolve out of a paint base which does not itself erode to any great extent. Requires removal of old coatings before re-coating. Can be sanded/polished to gives a smoother lower drag surface than most soft antifouling paints although ‘self polishing’ soft paints are intended to combine low drag with reduced need for coating removal.
3. Paints relying on non-stick properties rather than biocides, generally silicone based. ‘Aquacote’ and Hempel ‘Silic-one’ are examples. Slime forms on the hull but is relatively easily cleaned, possibly while the vessel is afloat, or it is removed by sailing at speeds over 8 knots. A fairly recent development which is not yet widely used.
4. Coatings, generally epoxy, in which are encapsulated particles of pure copper. Occasional light sanding exposes fresh copper. I think copper ’tiles’ for bonding to a hull have also been available. Also, at least one yacht has been built from copper-nickel alloy which has inherent anti-foulding properties.
5. Methods that do not use any coating on the hull – ultrasound, electrolysis or a giant bag enclosing the hull of a moored boat with treated water within the bag.

It would be good to hear of peoples experiences with the various options, particularly those options which may become the only options if copper based anit-fouling paints are banned.