Number of Bottom Paint Coats

[Juho]

Originally Posted by sailorboy1

237 views, only 5 poll votes :-(

Could not vote because of annual haulouts (the sea freezes) and one thin layer is enough (in the Baltic Sea).

[sailorboy1]

Originally Posted by Juho

Could not vote because of annual haulouts (the sea freezes) and one thin layer is enough (in the Baltic Sea).

yeah, there's lots of votes now but I wonder how many read the part about not hauling out for at least 2 years

[a64pilot]

Originally Posted by thinwater

And the downside is loss of adhesion and more frequent stripping.


A compromise.


What we need to do is get someone to evaluate how much longer 1 vs. 2 vs. 3 coats lasts. I'm on it.

Even then it depends greatly on the paint too, whatever was used on my last bottom job was soft as heck, when I would clean the hull I could see it coming off, a whole lot of it is gone, however the paint underneath seems to be still active and nowhere near as soft. I only had it on for a year and put another bottom job on, so maybe that works too?

My Swag is if it’s a very soft paint, go ahead and layer it on, cause it’s mostly going to come off anyway, if it’s not so soft, then don’t layer it on cause your just going to shorten the intervals between stripping it off and or it coming off in layers on it’s own.

[fstbttms]

Originally Posted by powsmias

just voted.. i put 3 on and got some amusing feedback now and then from marina guys.

Boatyards know that multiple coats means hauling out less frequently.

[gamayun]

Originally Posted by Tayana42

sailorboy1, I responded in the poll that I use 2+ coats. But I use Pettit Trinidad which is a modified hard epoxy paint. It lasts 3 years in Southern California and Northern Mexico. I also have a diver scrub the bottom monthly.

This is what I use in NorCal, but it was 2 coats on hull with 3 at the water line and rudder. It has been 2.5 years during which I cleaned the bottom with a light shop cloth about every 6-8 weeks. There are a few "streaks" around the keel where it is just starting to show through. I will be hauling in January mainly because I don't want to change the shaft seal in the water, but it would have likely been good enough for 3 years. My intent is to put 3 coats around the keel this time.

[thinwater]

Originally Posted by sailorboy1

... And yes how long the number of coats lasts in real life is the question. Practical Sailor tests don't reflect real boating life as the panels just sit, never move, and aren't cleaned. In real life people (at least me) have had to have the bottom cleaned once in a while.

1. Very true. One the other hand, controlled comparison on real boats is tough, since every boat and every location on that boat is different. Some of this has been done, but comparisons are uncertain.


2. Soft paints don't get cleaned, or rather it shortens their life if they are. I also suspect 95% of boats in most areas (including hard paint) are never cleaned. Not smart, but true.


3. PS did a test of cleaning methods for soft paints last year. The short conclusion was don't, not until very near the end, and then very gently.

[sailorboy1]

Originally Posted by thinwater

3. PS did a test of cleaning methods for soft paints last year. The short conclusion was don't, not until very near the end, and then very gently.

I can’t agree with this. You have to clean them when they start having growth on it. That was over 1.5 years ago when the paint was 1 year old for my current bottom.

I’ll look for the article (the online search on PS is crap)

[thinwater]

Originally Posted by sailorboy1

I can’t agree with this. You have to clean them when they start having growth on it. That was over 1.5 years ago when the paint was 1 year old for my current bottom.

I’ll look for the article (the online search on PS is crap)

The wonderful thing about sailors is that they don't agree on anything!


I exaggerated just a bit. Cleaning may be needed, but eventually, it shortens the life of the paint. Toward the end, depending on the paint, some cleaning extends the useful life. But with soft paint, only a little gentle cleaning until the end. If more than that is needed, you are at the end.


https://www.practical-sailor.com/iss...l_12392-1.html
https://www.practical-sailor.com/iss...e_12393-1.html

[sailorboy1]

I found the PS article, it was basically Duh

One of the purposes of applying additional coats of bottom paint is that you can clean it and still have paint. I also don't believe a boat needs to do 7 knots for ablative paint to work as the PS article says.

But this is a side topic. The topic of the thread is:

How many coats of ablative are cruisers (those that don't haul every year) using?

[Don C L]

Yeah the poll didn't match what I do too. I went with 2 coats of the Petit hard stuff and then I had a bunch of ablative from somewhere so that gave me a coat around the waterline and rudder too. I do not have the boat cleaned until I am ready to go somewhere and its been 3 years and it still only has a soft moss that wipes off pretty easily when it is time to go. BUT, where I am my slip is subjected to brackish water often so that probably figures into it.

[RSH]

Originally Posted by sailorboy1

237 views, only 5 poll votes :-(

I didn't vote because I haven't had to redo the ablative paint on my boat yet, so I'm mostly reading to see what other people do.

I do plan on doing the "signal layer" like others have done. In my case, the last time it was done was Nov 2016 with some (to me) ugly blue paint, so I'm going to leave that and do 2 coats of black over it since the blue isn't totally worn out.

When I see that ugly blue again, I'll know it's time to redo it...

[sailorboy1]

I wonder if people don't do more coats if using the expensive (more that is) paint. In the past in the Northeast I used 2 gallons. When I last did the bottom I used 3 gallons and put on at least 3 coats plus the extra at waterline and had a little left over. Using the various "how much paint" calculations I get 3.5 gals to do 2 coats and the extra waterline coat (which is less than I used last time for more coats). I don't want to buy that extra $300 of paint if not needed, but if it gets an extra 6 months it is a bust overall considering the haulout and related costs.

[sailorboy1]

Originally Posted by thinwater

The wonderful thing about sailors is that they don't agree on anything!


I exaggerated just a bit. Cleaning may be needed, but eventually, it shortens the life of the paint. Toward the end, depending on the paint, some cleaning extends the useful life. But with soft paint, only a little gentle cleaning until the end. If more than that is needed, you are at the end.


https://www.practical-sailor.com/iss...l_12392-1.html
https://www.practical-sailor.com/iss...e_12393-1.html

I read those articles again.

I wonder how "soft" the ablative test paint was in the article. As an example Interlux ACT is a LOT softer than CSC. Their info says to not in water clean ACT, but that you can the CSC. I've used both and you definitely can just wipe off the ACT in the water (bottom real clean after thought).

A lot of the higher end ablatives make a point of saying they are a harder copolymer, which will handle some light cleaning. I also notice those (at least for Seahawk) are the better performers in the longer time frame PS tests, even though they don't get cleaned other than a bucket wash.

I know at the 1 year point of my CSC I had small hard growth all over my bottom and it had to be scrapped, but this didn't seem to release a lot of paint into the water. Yet 3 months ago I cleaned the bottom and there was lots of paint in the water, which may just mean I've gone through the CSC and am at some older ACT.

[thinwater]

Originally Posted by sailorboy1

I read those articles again.

I wonder how "soft" the ablative test paint was in the article. As an example Interlux ACT is a LOT softer than CSC. Their info says to not in water clean ACT, but that you can the CSC. I've used both and you definitely can just wipe off the ACT in the water (bottom real clean after thought).

A lot of the higher end ablatives make a point of saying they are a harder copolymer, which will handle some light cleaning. I also notice those (at least for Seahawk) are the better performers in the longer time frame PS tests, even though they don't get cleaned other than a bucket wash.

I know at the 1 year point of my CSC I had small hard growth all over my bottom and it had to be scrapped, but this didn't seem to release a lot of paint into the water. Yet 3 months ago I cleaned the bottom and there was lots of paint in the water, which may just mean I've gone through the CSC and am at some older ACT.

The paint was Petite SR40/WM PCA Gold.


No question, every paint is different and every area is different. For example, I've used CSC and PCA; they both lasted exactly the same time, with CSC better tolerating cleaning, and PCA requiring less cleaning. I've used other paints as well. But did I sail them all the same? Probably not. Different marinas in the same town can be different. The best such articles can do is communicate trends.


Frequent fast sailing is an interesting question. I know that a long day at 8-12 knots will remove light, soft growth almost as well as a scrub. 6 knots doesn't seem to do this, no matter how far. But once the paint starts to fail and the growth is better attached, sailing no longer helps as much.


In cold climates growth stops in the winter. Soft growth from the prior season falls off.



It's complicated. I suspect the best number of coats varies with the area. Some people want to haul every 2 years for inspection or for work that needs done. 3-4 coats are probably better in high fouling areas and for sailors that want to go 3-4 years. No one answer.

[kmacdonald]

I put on one coat every year. I store the boat on land for three months a year.