When I had a new rudder made for THE HAWKE OF TUONELA, the warranty stated that it would be voided if I applied dark antifouling paint because the builder had conducted tests that demonstrated bright sunlight on dark antifouling could cause a dangerous rise in temperature in the foam core resulting in expansion and delamination. I did not know that and am not certain it is significant. But with a preference for dark topsides, I have generally used white or nearly white antifouling for contrast anyway.
However, I just made a reservation to haul GANNET from the water on Feb. 21 and I’m going to paint her bottom black.
Driscoll’s will allow me to do my own work. An increasing number of boat yards won’t. But there are rules, one of which is that I buy my anti-fouling paint from them. While they can obtain other paint, including Petit’s VIVID, the yard paint is International’s Ultra, a good hard antifouling that comes only in red, blue, green and black.
Luis, the diver who has been cleaning GANNET’s bottom, tells me that the two coats of white VIVID I applied in May of 2012 are gone and the bottom is essentially down to the barrier coat again, except perhaps for the four vestigial diamonds of VC17.
Putting a couple of coats of hard antifouling in a contrasting color as a base for subsequent ablative paint is a good idea. I’ve checked compatibility and both Pettit’s VIVID and International’s Micron can be applied directly over Ultra. I think I can get both in New Zealand, and with white over black, if GANNET becomes a pinto below the waterline, I’ll know the ablative has worn away.
Of the four choices, I think black will go best with GANNET’s platinum and white. Who knows I might even like it and continue to take the chance and use Ultra. A lot of boats have been using dark antifouling for a long time.
One of the major advantages of hard antifouling is that it can be scrubbed vigorously.
One of the major disadvantages of hard antifouling is build up. Eventually all those coats will have to be removed, a brutal task as I know from my VC17 ordeal.
One of the major advantages of being old is that even if I continue to use Ultra, it won’t build up that much in my lifetime.
I fly west three weeks from today.
At the moment San Diego is 82°F. Evanston is 22°F.
