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Ken Buck
06-21-2002, 01:33 PM
Some practical questions about the use of bottom paint on small boats which may or may not spend all their time in the water (in this case, we're talking salt water)...

1. Some of the lower-end antifouling paints (such as Interlux BottomKote or Gloucester Sea Jacket) indicate that the boat should be launched within 24-48 hours of painting to prevent exposure the air from affecting the paint and presumably preventing it from working properly. (some of the more expensive versions have less-restrictive time-to-launch recommendations)

So, the question is: how critical is this?
In the Real World, people can't always fit into the time schedules dictated by the Paint Manufacturer Lawyers. If you can't launch for 3-4 days or maybe a week, is everything hopeless, do you need to recoat, or is it not that big a deal? Does recoating even "fix" the problem, and if so, why? Or do you (in theory) need to take the paint all off and start from scratch?

2. What about boats that may be in and out of the water during the season - say, you pull your boat back onto land
for a week or two and then relaunch back onto the mooring. In theory, do you need to repaint the bottom? After all, it's being re-exposed to the air, which was supposedly forbidden in the first place.

3. What about boats that are exclusively sailed from a trailer - anti-fouling supposedly isn't needed in this case, so do you just paint the bottom with the same kind of paint that you used on the hull?
(although one might think that trailer-sailed boats are still being exposed to the Marine Greeblies during the period of time (hours or days) that they are in the water... so maybe anti-fouling is stil a good idea in this case?)

4. This all leads to a question of whether there is a better-suited type of anti-fouling paint for small boats (such as the epoxy-based types or whatever). As long as the cost isn't completely outrageous (I suppose some might say that bottom paint cost is outrageous by definition), does anyone have recommendations for owners of small wooden boat owners (e.g., dories). The low-end paints only last one season, some of the higher end ones may or may not last more than that, but my goal is to do the best thing for the boat with a reasonable amount of effort and cost. I've read some of the text on anti-fouling paints in magazines, catalogs, etc. but it is somewhat confusing, so any remarks based on actual experience would be helpful.

--

For the record, I've owned my boats and have been breaking some of "the rules" for years without apparent harm, but am wondering if there is a better way to do things in the future. Also, I think others may be interested in these kinds of remarks.

Thanks for any comments and suggestions!

Nicholas Carey
06-21-2002, 03:45 PM
You might consider CopperPoxy (66% copper in epoxy), http://www.copperpoxy.com/copperpoxy.html,

Needless to say, it lasts a long time on the trailer.

Scott Rosen
06-21-2002, 08:46 PM
Hi I am Aviana Rosen. I am 9 years old and am Scott Rosens little girl. My dad built us a dinghy called the nutshell pram, and i will be painting it!!! We are going to use "Kirby's Bottom Paint", it's green. I always like to help my dad paint and varnish stuff for our sailboat, and dinghy. We named the dinghy Cricket because while dad was working on it there was a cricket that kept him company. this is the first year we are using Kirby's Bottom Paint. (we hope it comes out good) We want to keep all the barnicles and yucky sea stuff off the bottom of cricket. :eek:

Keith Wilson
06-23-2002, 08:40 AM
I wouldn't use the low-end soft bottom paints on anything that would be hauled and relaunched without repainting, for two reasons:
- The paint really does lose some of its effectiveness when it sits out of the water; how much I can't say exactly, but I can tell you from experience that the note on the can's not just a lawyer's warning.
- It's very soft, and hauling and relaunching can scrape a lot off, leaving bare areas for the critters to get in.

For a boat that was going to be intermittently out of the water (mostly in) I'd use one of the hard epoxy (non-ablative) paints, which, although they cost more, last longer, can sit out of water with no ill effcts, and don't scrape off as easily. I've had good luck with Petit Trinidad, FWIW. Although it certainly galls to pay over $100/gallon for the stuff, it lasted over two years in San Francisco Bay. Other kinds might work better for your local conditions.

For a boat that will mostly live on the trailer and be only intermittently wet, you're right; no anti-fouling paint is needed, and whatever you used on topsides will work. I personally like epoxy and graphite for the bottom of small trailer-sailed boats; it's hard, slippery, and looks nice. It takes quite a while for the little buggers to take hold, and drying out kills them very effctively. I'd say even a week or two isn't enough to worry about.

[ 06-23-2002, 09:54 AM: Message edited by: Keith Wilson ]

cmorse
06-24-2002, 02:07 PM
I've used Interlux Micron CSC Extra sucessfully on both of the Devlin boats I've owned. It is designed for both trailering and sitting in the water for extended time periods. In this part of Alaska, my current boat is only in the water 4 months, tops. After that, she is on the trailer. You only need to scrub it to activate it the following year. It's protection should last 2-3 years...