Antifoul overload or delamination?

[Johnmcj]

Hi

I came across this and was wondering if this is a sign of an issue with the glass, or, as someone else has said to me, simply the result of slapping on new anti foul year after year without proper maintenance. Is there any issues with this?

[marcjsmith]

john,


my moody had 30 years worth of AF on it when I bought last year. I had lots of the spots like that and in some areas, large swatches of bare hull that the Af had peeled off. thinking either overload of AF or bad surface prep before the first coat. no matter I took it down to bare glass everywhere and started fresh.


This looks a lot like AF peeling rather than delam. a sander with 60 grit and you'll find out easily enough...

[tkeithlu]

Plus one on Marc's diagnosis. Wow! that's a bunch of not very adherent paint. Methinks you are going to see a lower waterline and higher hull speeds when you get all that off!
You could just pry it loose and make another boat out of it.

Yeah on the 60 grit. Be careful - you don't want to sand away the hull.

If it were delamination, you would expect to see bulges and loose fabric edges.

[Johnmcj]

Thanks, these are reassuring answers.

[GordMay]

Greetings and welcome aboard the CF, John.
IMO: What the previous contributors have said.

[sailorboy1]

bottom paint, bet a power washer would take most of it off

[rslifkin]

Some paints tend to do that if they build up too thick. They start to absorb some water, lose adhesion, etc.



Definitely give it a good blast with a power washer and see what comes off. Some light work with a scraper will probably take a bunch more off, then you can sand what's left to get it smooth. You may end up taking it all the way down, or you may end up leaving a thin layer of well adhered paint, depending on what you find as you scrape and sand.

[ferrailleur]

Soda blasting!

[Sailmonkey]

Huh.... looks like our boat. It’s just years of bottom paint.

[marcjsmith]

Originally Posted by ferrailleur

Soda blasting!

I tried to sand, got 20%, complete, then tried a chemical peel. It worked ok, but in the end I stroked a check for the soda blast. Money well spent.

[sailcrazy]

Following. Due to Covid, our boat has been up on the hard now for just over a year...it's in Puerto Rico and we're in MN. And we just now got a report that we have significant "scaling" on our hull, whatever that may be. The contractor(who says he does not do stripping or heavy sanding) will gladly recoat the bottom, again, but now will not "guarantee" the work, and we're looking for ideas. We have used the same anti-foul (Micron 66) and have recoated the hull every year since 2009.....Micron 66 is ablative, and some has sloughed off during our sailing each 6-8 months season, but still we have maybe 11 years of 1-2 coats/year on the hull. Just prior to this we had the hull
stripped and peeled, and put a new barrier coat put on. The peeling and redoing the gelcoat and barrier DID stop our osmosis/blister issue, but now this???Looking for ideas and solutions!

[skipgundlach]

Originally Posted by tkeithlu

Plus one on Marc's diagnosis. Wow! that's a bunch of not very adherent paint. Methinks you are going to see a lower waterline and higher hull speeds when you get all that off!
You could just pry it loose and make another boat out of it.

Yeah on the 60 grit. Be careful - you don't want to sand away the hull.

If it were delamination, you would expect to see bulges and loose fabric edges.

Amen to that!

Our boat had a massive bottom refit in 2011-12, and we'd hired a guy who was an ASE fiberglass certified auto guy (Corvettes, particularly) to take off the paint - but he not only took off all the bottom paint but the barrier coat a PO had applied after peeling due to blisters.

Get a glass blaster outfit in there and take it off down to the gelcoat or barrier coat, and do any cosmetics or structural repairs you need before redoing the barrier and bottom paints.

Our adventure can be seen here - and we DID have legitimate delam due to uncatalyzed water-soluble materials (WSMs) - story elsewhere on CF about resolution for that, and full story on the paints we used - here's the photo link:

Pictures: Flying Pig 2011-2012 Refit/Bottom Job

In it you can see what delam (blisters) looks like vs your paint...