On Wed, 28 Apr 2010 19:57:51 -0500, brian whatcott
wrote:

It's paradoxical I know: the idea of anti fouling is to deter marine
organisms - and that's almost a definition of toxicity.
Oh well....

Yes, and the jury is still out on anything not containing copper or
tin. They both work pretty well. Tin is still available if you know
where to look.