[nestorph]

I sail in Raritan Bay (off the NJ coast). For years I've been faithfully sanding the bottom and applying a fresh coat of West Marine CPP paint. However, I've read blogs where people are getting more than year from their application. While I'm willing to apply another coat this year, I was wondering if I could just get away with power washing the bottom and doing the application or do I still need to sand first?

 

[CalebD]

I've been using the same paint as you (WM CPP) for the past 10 years too. I sail a little north of you up the lower Hudson River Tappan Zee area.
I have applied the new paint after only power washing & spot "cleaning" without much sanding at all. Results varied from year to year as far as antifouling effectiveness.
If you want to try going 2 seasons with this paint I'd love to hear how it works out for you. I've been using 1 gal./year for our 27' boat = 1+ coats.

 

[JimsCAL]

There are different types of bottom paints. First is ablative versus hard epoxy. Second is single season ablative versus multi-season ablative. CPP is an ablative, but I think it is single season. The West Marine PCA is multi-season. With a multi-season ablative you can get away without painting if there is sufficient paint left on the bottom. A light scrub with a Scotchbrite pad is enough prior to adding a coat as long as the bottom is in good condition.

 

[smurphny]

I'd like to know more about the actual longevity of expensive paints. Of course, the paint companies want you to use paint every year but is it actually necessary? Build-up of thick, scaling paint is a problem and I wonder whether repeated coating is ACTUALLY necessary. I always thin down my bottom paint to try to avoid build-up but have always painted every year. Just what is the chemistry that makes a perfectly good, well adhered paint of any kind which has been on over the winter suddenly be no good in the spring? Has the chemical composition changed? Has the toxic stuff evaporated? Does cupric oxide leach out? Chemists please chime in with some actual info on this. Last year I put expensive "tropical" quality paint on (Interlux Ultra) and wonder whether I can avoid spending another $200 this year if it's really not necessary.

 

[jzk]

I have VC-17 on the sailboat and Petit white ablative on the powerboat. I must admit, I like the white ablative very much. We are in Lake Michigan, so that is different, but we get great life out of it. And it is way easier to work with than VC-17. It is true that VC 17 is more of a race paint, but I am not sure that the white ablative wouldn't work just as well because it tends to maintain a really nice, smooth finish all year.

I did get a nice system down for doing VC-17 with a roller (my yard won't let you spray). I put only as much in the tray as will fill a roller. Otherwise, it just dries in the pan. Also, when going to the second can of VC17, I put the copper powder in the somewhat empty first can, then I pour the solvent into that first can, close, and shake to mix. It works much better than adding the powder to the can of solvent as it sits on top requiring stirring and half of it just blows everywhere if there is any wind.

 

[SloopJonB]

Try it and see what happens. Worst case you'll have to pay for a diver to scrub it or haul earlier than otherwise.

 

[nestorph]

I did what I should have done first, namely, "read the instructions"! The West Marine site provides information about CPP. It's definitely a one-season paint. To add insult to injury, they recommend two to three coats per season and sanding the previous year's coat.
I ended up lightly sanding and applying a single coat which has worked well for me in the past. There goes my short cut...

 

[Omatako]

It's always difficult (and probably unwise) to comment on products or growth rates in areas you don't know but principally what I'm about to say I believe fits a lot of scenarios.

I use a paint that is also punted as a one-season ablative paint. I started hauling annually and the boat was always quite clean and the pressure wash resulted in rivers of blue water flowing away from the boat. So after the second annual haul-out, I left the paint for two years.

When I hauled and washed, the river was less intense but still a strong blue. And when I wet-sanded the boat I got a lot more blue off the boat. So I left it for three years.

Now that is my routine. And the fundamental rule I follow is I don't touch the paint for any reason. I don't try to clean it, I don't even rub my hand over it (which lifts a considerable amount of paint). And after the first three year session, the bottom still came clean with just a light wash. I had to request a high pressure wash to get as much off as possible to reduce the sanding.

Obviously YMMV but the test is in trying it. As another post said what's the worst that can happen.

We live in an area where the boat is in the water 12 months a year.

Now, if only I could find something better than PropSpeed . . . .