My paint has come off !

[Dave-Fethiye]

I recently put my wooden (planked) boat in the water after painting her.

I had sanded the wood and then applied a coat of marine primer before applying two coats of antifouling.

After putting the boat in the water two weeks ago, in about four places there are now patches where the paint has come off!

The areas are about 6" x 4" and the bare wood can be seen.
I have no idea why the paint came off in those areas. What can I do about it ?
Will my planks start rotting ?

Someone wrote that you can apply anti-fouling under water - is that correct ?
Should I do that or should I just leave till the next haul out - maybe four months away ?

The boat is in the mediteranean sea ( South West Turkey).
Thanks for any advice.

[Dave-Fethiye]

I was told by the paint suppiers to use the primer and it did say on the can - antifouling primer.

Do you just put on antifouling with no primer then ?

[PAR]

Some bottom paints require primer and others don't. If the primer lifted (taking the anti-fouling with it) then you likely had some sort of surface contamination. Most often I've found (when this occurs) that an oil soaked area of planking was the real culprit. These are commonly found around the engine, usually at the garboards where it drains down and pools, at thru hulls, stuffing boxes, rudder ports and the LWL where floating oil and other contaminates can soak into the planking.

These oil soaked areas can be a real pain in the butt, to sanitize well enough to accept paint again. Bleach, heavy sanding, several coats of epoxy to seal down the area sometimes isn't enough.

Another issue that could be a possibility is a not quite well mixed primer. A separated area of primer that didn't get well mixed, could get brushed/rolled on and though it looked like the rest of the primer, it could have been just vehicle (solvent) or solids (pigments). I always have the paint shaken twice the amount of time it usually takes on normal paints, when working with bottom paints (which are quite thick) and then I still mechanical stir the paint (paddle on a drill) when ready to apply.

Lastly, the only other thing I can think of, is an incompatibility with the two paints (primer and bottom paint). If the bottom paint had solvents that could attack the primer, I can see problems like this, but they'd likely be wholesale over the bottom, not just isolated spots. This problem usually shows up right away, in the form of fish eyes, orange peel, etc., not later after cure. The bottom paint manufacture will have recommendations for primers to use.

If you're hauling in a few months, then wait until she's on the hard again and look over the areas. Scrape the surrounding areas to see if it too is ready to lift. If some areas seem very well attached and others, ready to fall off then I'd suspect the surface prep or substrate (planking) contamination. If the whole of the bottom seems like it could easy be removed then you have other issues, maybe paint related.

Most paint issues are usually prep related.

[Dave-Fethiye]

If it is due to oil in the wood - then I guess it is safe to assume that there is not much chance of any wood damage ( rot etc )due to lack of paint as the oil would protect it pretty well ?

[PAR]

As the senior chief mentioned, wood, living in salt water will not rot, though marine beasties can eat it. Rot wouldn't be my concern as much as moisture gain from the exposed planking. If she's a carvel hull, (my guess) then she'll be fine until haul out in a few months, when you can get another look see at the old girl and address this issue.

[USCGRET/E8]

Originally Posted by Dave-Fethiye

I was told by the paint suppiers to use the primer and it did say on the can - antifouling primer.

Do you just put on antifouling with no primer then ?

If it said to use primer, did you use the same brand as the paint? How did you prep the surface before primering?
What I have seen done that seems to work well esp on the older boats, , on bare wood apply a thinned coat of antifoul. This will soak into the wood. Next coat, thinned just a little. Top coat unthinned. The antifoul was of the soft type.
But if you did everything to the letter as posted on the can, then the wood or whatever you put the primer to was contaminated as mentioned above.
It's usually not advisable to paint on real humid days as well.

[Dave-Fethiye]

Thanks for the warnings about worms etc.



How about if I dive down and rub grease on the wood - will that stop the little blighters ? Someone said that grease sticks to wood under water.

[Bergalia]

Take Par's advice. Drag her out on the hard - let her 'dry out' for a day or two, and then have a really good look at the 'peeling patches'. Scrub well with metholated spirit to remove last of the moisture and any oily contamination. Then apply a couple of layers of the 'traditional' jallop - 1 (one) third boiled linseed oil; 1 third white spirit; and 1 third timber preservative. Apply until timber can suck in no more. You'll get a semi-gloss surface which will accept most paints - even without an undercoat. Finally below the water line you'll find 'pitch' is hard to beat as an anti-foul. Worms - even the Torredo find it indigestible.
Sure, you can aply a layer of grease 'underwater' - BUT it will quickly wear off.

[hansp77]

Bergalia,
where do you get pitch from these days?

In brief fit of madness, while looking into making a Currach, I tried to source some pitch (or bitumen). It was proving near impossible as I couldn't find any form of retail sale that would provide it. A couple of leads hinted that I might be able to buy it by the ton somewhere... but there seemed to be a heap of OH&S issues with it too (not that it concerned me, but made procuremnt of it more difficult).
My best hope seemed to be to approach some council workers doing some road work and offer them a case of beer for a few bucketfulls.

[Frosty]

Im not a wooden man but I see enough out on the hard here. They dont use primer ever. Grind off,--a quick caulking,-- and antifoul usually Jotun.

While I am on the hard there will probably be 4 or 5 wooden trawlers come next to me and get done this way. Boy do they stink---fish and deisel --lovely.

I thought worms were more of a problem if she is allowed to sit in mud, and there has to be a hole for them to get in. If you catch them early enough and can see them in the hole a blow lamp finishes them off.

Copper bottom it?? I mean copper sheet nailed on not copper paint. No hole though.

Bitumen,-- surely from the builders supplies. Thats what you slap on your kitchen extension roofs

[hansp77]

Frosty, most of the bitumen I was able to find at building supplies and whatnot was not pure bitumen. Hell, they even have water based stuff now.
Real bitumen, because you have to heat it to make it liquid, is a whole nother thing for OH&S, or so the people I tried to deal with where offering as an excuse.
I am sure there is some old store somewhere where you can buy it in a great sack for about five bucks- I just couldn't find it, nor could anyone point me there.

[Frosty]

Oh --I dont know ,-- whats tar then? Or is it the same thing, isnt that the stuff they pour between the deck planks.

[Bergalia]

Originally Posted by hansp77

...My best hope seemed to be to approach some council workers doing some road work and offer them a case of beer for a few bucketfulls.

Right on target Hansp. In NSW a 'slab' of beer will get you more than enough to coat your 'bottom' - probably enough to do your driveway as well.
As to 'health and safety' - just use common sense. Work in the open air, wear mask, gloves and goggles. Keep pitch 'ladle' hot enough to melt contents - but not bubbling. Apply quickly, before pitch becomes too viscous (tacky).

Frosty, as far as I know pitch is a more refined version of tar. Tar will do just as well for antifouling.