Used Behr Premium Porch and Deck (from Home Depot) on our Passagemaker Dinghy, with good success so far.  Easy to touch up.  We've not had any issues when swe've had her afloat with the mothership for several days at a time, either below the waterline or puddling in the bottom of the interior.  We don't leave the boat in the water for weeks at a time, though, so I couldn't say about longer term exposure, but the stuff is meant to be used outdoors and seems pretty durable for latex paint.

The only real trouble I've had was when I foolishly used acetone to clean up the stickum when taking off the expired state registration sticker.  Duh.

.....Michael

Laurance,

I used the S3 WR-LPU on my brand-x (not CLC)  sailing dinghy and am very happy with it. I would use it again on the next boat that I paint instead of finishing bright. Here's a picture of the inside of the boat after the last coat dried.

I prepared the surface with epoxy mixed with phenolic microballoons to fill the weave and to fair everything. After lots of sanding I applied S3 Yacht Primer and sanded most of it off again. I repeated that 2 more times.

Finally, I applied 3 coats of the WR-LPU. I used soft rollers and tipped it out with a natural bristle brush. The stuff self-leveled very nicely. For the last coat I added the cross-linker.

The whole process took a month of after-work and weekend time.

It's lasted just fine for 9 years, needing only the occasional touch-up where there was a metal-to-boat collision.

Have fun,

Laszlo

You may want to take a look at Wetlander by Wearlon.  It is a two-part water based coating designed for use below the water line.  I used it on my brand-Y sailing skiff and am very happy with the results.  I find it to be very durable and was very easy to apply.  It is very low friction so you wont want it anywhere that you may walk. The only negative is that it is not cheap.

 Thanks for all the replies,

Laszlo, well done for all for all that sanding, surely 9 years was a good pay-off. But what is the deal with the crosslinker anyway, why would one chose not to add it?

Mark N, in my hurredly written post i negected to mention i was thinking primarily about about a coating for the interior of a ply/epoxy boat. But since you mention Wearlon, that does seem like a really good option for a waterbased bottom paint, thanks.

Laurance

Two things happen once you add the crosslinker - first, the coat of paint will cure very hard; second, after 24 hours you have to re-crosslink the paint after which you have another 24 hours to use or discard it.

Crosslinked paint cures so tough that it's difficult to sand. On the theory that there may have been defects that needed sanding out, I saved the really hard coat for the final one. That and not having to discard the unused paint. That stuff is not cheap.

Laszlo

Mark, 

Wearlon seems to be one of those companies stuck in the 1950s that won't put its prices on the website. How expensive are they?

Laszlo

   I was thinking about Wearlon Wetlander for the bottom of my SW Dory.  I was planning on doing Wearlon frfom the bottom up to the top of plank 2 and brightsides paint for plank 3-4 and the inside.  Any issues I should expect doing it that way?  Any reason to use more/less Wearlon ie any advantage to painting the whole outside with it?  Thanks.

  Lazlo, you can see the prices if you go into their online store.  The 2 layer kit (1 quart each primer and topcoat) costs $158 and covers 50 sqft.  It is really not that much more expensive than a quart of Interlux primer and a quart of their two part.  

Rich, you will have no problem doing as you propose.  You will have to do the Brightsides first then the Wetlander.  I got a great seam using fineline tape to mask.  Make sure you follow the dirstions regarding when to remove the masking tape or it will be locked forever on your boat.  I would not use more Wetlander because it is more expensive and has a slightly orange peel texture.  Brightsides or similar will look far better above the water line.