Bottom paint after 5 years out

[earthbm]

Originally Posted by Boatyarddog

Here in PNW, I have friends that just "reactivate the coating" by scratching up the coating with a scotch brite pad, works for them.

Bottom paint, ablative types, when exposed to air get a "patina" that seals the surface, sometimes seen as green, or brown.
This is my Opinion, and have heard it more than once.
Not going to respond to posts as its not an arguement, as its just a possibility, it works.
Boatyarddog

Thank you!

[MicHughV]

A selling point of anti-fouling paint manufacturers is typically the percentage of copper contained therein.
I've always been a fan of Pettit Trinidad...for no other reason...than it typically has a very high copper content.
I usually apply two coats at haul out. My experience has been that it will last at least two years....sometimes three, depending where I go.
Over the years I've tried various other products, all claiming this, that or the other, but at the end of the day, the Pettit Trinidad won the day for me, primarily, as far as I'm concerned, it's high copper content.
I am by no means an expert on the subject, just adding my 2c to the pot.

[Boatyarddog]

Originally Posted by earthbm

Thank you!

Your welcome, I'm sure some quick whip will disagree.

It's painted, use it!
Unless you won't haul for years.

Me I don't bottom paint, but I've got enough strength to scrape a couple times a year.
Saves some cash, and has no effect other than not being a racer, ha, I don't care for the extra 1/2 knot.
As well who can prove MY fuel use is more, you can only go hull speed through the water.
And I do!

What I've heard is from a well experienced sailing couple, who did this many times.
Worked for them.

[fstbttms]

Originally Posted by earthbm

Any professional wisdom to share?

Yes. Hard paints are rendered inactive by prolonged exposure to air. It is not (of course) because the copper biocide had evaporated (or some other ridiculous notion) but because the delivery mechanism within the paint is made inert.

[ParL]

Originally Posted by fstbttms

This study essentially says that the amount of copper in an anti fouling paint is irrelevant and that in freshwater, no anti fouling paint is needed at all. Maybe all that is is true in Sweden (where the study was conducted) but it isn't the case in California, I promise.

Sweden has three possible regions to keep a boat


1. One of the lakes.

2. The Baltic, with brackish water (variable depending on location)
3. The west coast: pretty much the north Atlantic


The article was open source (nice of them!): apparently one of the main questions was copper based paint and various salinity. And they made the point that



1. many paints released excessive amounts of copper
2. release increased with salinity


Number two might actually be intentional, since fouling increases with increased salinity (among other things)



In all cases Sweden has fairly chilly waters, so even a lake would not have a long warm period, and in most cases months of ice cover annually. I think California has a slightly warmer climate?

[HopCar]

I think fstbtms is on the right track. The surface layer degrades in air and skins over.

Do you know what paint is on the bottom now? Some paints can be left out of the water longer than others.

I’m not sure it matters but the most common biocide in bottom paints is not copper (Cu) but Cuprous oxide (Cu2O).

If you aren’t going to repaint, at least sand the surface some.

[earthbm]

Thanks guys. I will not repaint, but will touch up. Would be good to know what paint I have, but I probably won’t find out!

[sailorboy1]

Since the boat is hauled out I definitely would have painted

[bil56]

after 5 years on land, the antifouling has lost its effectiveness, I would take the opportunity to redo the paint ...

[earthbm]

Originally Posted by bil56

after 5 years on land, the antifouling has lost its effectiveness, I would take the opportunity to redo the paint ...

Thank you!
How?

Is there any chemical explanation? Or a lot of empirical evidence of boats with new bottom paint spending 5 years out on the hard, and then experiencing ineffective bottom paint?

[fstbttms]

Originally Posted by earthbm

Thank you!
How?

Is there any chemical explanation? Or a lot of empirical evidence of boats with new bottom paint spending 5 years out on the hard, and then experiencing ineffective bottom paint?

From Interlux Paints:

"Hard antifoulings do not retain their antifouling ability if kept out of the water, and cannot be hauled and relaunched without repainting."

Splash your boat now and find out if it's true. Then you can give us a first hand report on the results. Who knows? Maybe the manufacturers are lying. But you be the guinea pig, mmm-kay?

https://www.fawcettboat.com/images/I...ouling-101.pdf

[boatman61]

Originally Posted by earthbm

Thank you!
How?

Is there any chemical explanation? Or a lot of empirical evidence of boats with new bottom paint spending 5 years out on the hard, and then experiencing ineffective bottom paint?

Go over the hull with an orbital sander to remove the surface discolouration then launch her..
As said above you will know for sure soon enough.. depends a lot on usage and location how quickly but you should get at least one season out of it.

[Jim Cate]

depends a lot on usage and location how quickly but you should get at least one season out of it.

Dunno about that, Boatie! The paint could well have been kaput when she was hauled and a five year rest won't have helped that situation.

The cost of slipping is always a decent part of the cost of bottom painting, so I'd take advantage of her bein' on the hard now and just do it.


Jim

[Flying Monkey]

This is a great thread. Thanks to all who have contributed to making it so.

[boatman61]

Originally Posted by Jim Cate

Dunno about that, Boatie! The paint could well have been kaput when she was hauled and a five year rest won't have helped that situation.

The cost of slipping is always a decent part of the cost of bottom painting, so I'd take advantage of her bein' on the hard now and just do it.


Jim

Ahh... but ever the optimist I was working on the fact its a multi going on the info below the avatar..
Paint one side of the hull and one outrigger on one tide then cant her and do the other side next low tide..
That way just the price of the paint.. tide appears to drop 1.5metres that a way so it's down to finding a hard sand spot or slip to dry on.. plus a little help from a friend or 3 to speed things along.