Bottom Paint

T

Tad and Toby Jackson

New member
Since we have owned the Comfy Dory, we have used an ablative paint for the bottom as the previous owner had used it and we thought that we might be leaving the boat in the water at our dock more than we have. As it turns out, the times that the boat is in the water for more than a week are the times that we are cruising somewhere and on the move almost daily which keeps any growth on the bottom at bay. I would like to remove the ablative paint and use a hard shell glossy type paint that will last longer with better color than an ablative and hopefully increase the speed a bit. Any suggestions?

Tad
 
Tad and Toby Jackson":1fsqqkwv said:
I would like to remove the ablative paint and use a hard shell glossy type paint that will last longer with better color than an ablative and hopefully increase the speed a bit. Any suggestions?
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I guess what I have is an "un-suggestion," but the hard-shell, glossy paints I know of are not rated for underwater use, and, indeed, I have seen them bubble and fail pretty consistently where they even sometimes get below the waterline (for example, someone's topsides are painted with it but the boat sits down on her lines and so it's submerged a certain percentage of the time). This would be two-part linear polyurethanes such as Awlgrip. Two-part acrylic urethanes (Awlcraft 2000, etc.) wouldn't be suitable for underwater use either. It would be a major pain to remove either of them if they failed.

On the other hand, what I don't know is how they would react to one- or two-week dunkings, or if there is another paint that would be suitable that I just don't know about.

Given that the original gelcoat is suitable for what you have in mind, and given that you would have to remove it anyway to prep for paint, I think if it were me I would remove the bottom paint in the least-destructive-to-the-original-gelcoat way possible (perhaps a gentle paint stripper), and see if you can salvage it (with a compounding/wetsanding/etc.). Sprayed on gelcoat is not quite the same (as the original that was put on in the mold), so again, I would try/hope to salvage what you have.

In your favor, many times the prep work for bottom paint is a bit lacking in precision, so you may find that it comes off relatively easily and that the gelcoat underneath is in decent shape (for example, if the original mold-release wax is not adequately removed, paint adhesion is compromised).

I guess I would start by working on a test patch and then go from there.

Sunbeam :hot
 
Sunbeam always gives good advice. It is very difficult to remove bottom paint which is properly applied. The bottom should have been sanded, it may have had epoxy barrier coat put on (good), and it may have had an etching primer. Yes you can strip bottom paint off, but the gel coat will have to be carefully prepped--and faired. This can be expensive.

The two part LP paints will not do well in water. Applied gel coat may be subject to blistering because of poor secondary bond. Even a week can give growth--moving every day does not prevent that.

I would go to a multi season bottom paint--specifically Pettit "Vivid". This is a multi season bottom paint, which will look good, and hold up well. I am on 3 years with a boat which spends about 50% of the time in the water (mostly fresh water bayou, on a salt water bay) and the paint still looks great.

As for speed, I doubt that you will notice the difference. When I was racing sailboats, we would bottom paint--some would burnish, after spaying, others would do as we did; use the Scotch green pads or 6oo to 1200 sandpaper, and I didn't see any advantage to the burnished paint....
 
I would just like to offer that the reason your bottom stays clean when you are cruising is precisely because you are using an ablative bottom paint - that is how they work. Gelcoat will build up growth if you stay in the water, moving or not.

Non-ablative, or "hard" bottom paints are available (Pettit Trinidad, Interlux Ultra, etc.). They work by leaching their biocides to the surface slowly and will not blister when applied properly. Maybe you could look into those...

Cheers!

John
 
Tad, since you're boating in Florida, I assume you're referring to the hard bottom paints such as Trinidad that John mentioned above, versus the softer ablative bottom paints. In the water for a week without bottom paint there would give you a nice layer of "stuff."

On the sailboat, we used Trinidad, which is a good paint but it has a few aspects you may want to consider. First, it doesn't like to be out of the water. We found out the hard way when we shipped Our Journey from San Diego to Mobile. The Trinidad was peeling when it reached Mobile, a period of a week or so. Next, it needs repainting every few years, but unlike ablative paint, it just keeps on building up and those layers eventually need to be removed. That's not easy, sanding or chemical strip.

That's why I used ablative bottom paint on Journey On. The boat spends most of the time on a trailer and the Micron CSC isn't affected. Also it's like a bar of soap, it wears off so I just re-coat it on the trailer. I just used the last of the Micron, so I'll try a cheaper paint, but it'll still be ablative.

Boris
 
I had the worst luck finding a bottom paint that worked for more than 3 months in the water. I tried both hard and ablative paints with no success. I finally discovered Pettit Ultima Eco. I'm on the second season and the bottom still looks great (my boat is in the water 6 months a year).

Good luck with your research.
 
just got done helping a buddy strip off bottom paint on his 19' arima. and restore back to the original gel coat. it was a lot of work don't even want to add up the hours. with a lot of chemical strippers and wet sanding. looks great now. my new to me dory has bottom pain on it and I would like to get it back to gel coat as we do not moore boat. but after helping him with his I will not start that project on mine... and will probably never offer to help any of my other buddies do theres.
 
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