It has been pointed out that, for paint to be anti-fouling, it generally does this through being hostile to biology. I recall reading about some coatings that seek to be resistant by providing a texture that makes it difficult for organisms to attach themselves, but I think these are largely experimental still. They are certainly not widely used, yet.
But ... I learned something recently. When we purchased our boat, it was moored in Tacoma. At the survey haulout, there was NO antifouling paint whatsoever. It was covered with football-sized clusters of mussels. They cleaned it up but did not bottom paint, at that time. It then sat about 3 weeks before we got to look at her again. By that time, it had a substantial beard coating everything below the waterline. We gave her a quick scrub and took her out for a sail and most of the visible gunk was gone except for some patchy surface slime. But, within 2-3 days, the beard was back.
I mention this because this hasn't been our experience in our home port of Bellingham. I was amazed at how fast the growth happened in Tacoma. We could leave the same boat in Bellingham for several weeks and just get a little bit of beard right at the waterline and some slime starting to coat surfaces. The water must be colder? In general, we found the water down south quite dirty, by comparison.
In other words, there are some regional differences, even within the PNW.
We paid particular attention to this because we considered not applying bottom paint at all until this fall, since the boat will be sailed at least 3-4 days a week, and will move around all summer. Based on our trip up from Tacoma, this week, we think we could skip bottom paint entirely, so long as we keep sailing her regularly. (As it happens, we have to haul out for some other reasons, so we are bottom painting next week, but I don't think we really need to until this fall when we will sail less consistently.)
I know this doesn't really answer your question, but thought I'd share our recent experiences, as they seemed related to the topic.
But ... I learned something recently. When we purchased our boat, it was moored in Tacoma. At the survey haulout, there was NO antifouling paint whatsoever. It was covered with football-sized clusters of mussels. They cleaned it up but did not bottom paint, at that time. It then sat about 3 weeks before we got to look at her again. By that time, it had a substantial beard coating everything below the waterline. We gave her a quick scrub and took her out for a sail and most of the visible gunk was gone except for some patchy surface slime. But, within 2-3 days, the beard was back.
I mention this because this hasn't been our experience in our home port of Bellingham. I was amazed at how fast the growth happened in Tacoma. We could leave the same boat in Bellingham for several weeks and just get a little bit of beard right at the waterline and some slime starting to coat surfaces. The water must be colder? In general, we found the water down south quite dirty, by comparison.
In other words, there are some regional differences, even within the PNW.
We paid particular attention to this because we considered not applying bottom paint at all until this fall, since the boat will be sailed at least 3-4 days a week, and will move around all summer. Based on our trip up from Tacoma, this week, we think we could skip bottom paint entirely, so long as we keep sailing her regularly. (As it happens, we have to haul out for some other reasons, so we are bottom painting next week, but I don't think we really need to until this fall when we will sail less consistently.)
I know this doesn't really answer your question, but thought I'd share our recent experiences, as they seemed related to the topic.