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I'm removing all the bottom paint to fix a couple of places where the keel has impacted the trailer, or a rock while beaching etc. Basic glasswork, no prob.

But what isn't standard issue is that the space between the outermost lifting strake and the chine was filled w/ bondo (or similar) and faired flush. I guess the proposed benefit would have been less hull slap while poling (skiff). Anyway, about 8 years ago the boat lived in the water, and I noticed blisters in this area. Pulled the boat, let it dry, ground em out, filled with 3M vinylester putty, and put on a coat of epoxy barrier. Worked pretty good.
The boat hasn't lived in the salt now since that time (except for a week here and there) but now that I'm spending alot of time under the boat, I'm noticing quite a few hairlines in the barrier coat, and some new, tiny blisters. So when I open these up by sanding/grinding it exposes bondo, which seems fine until a few hours later. Then the bondo has turned really dark (like it's wet) and it starts weeping a dark semi-viscous fluid. Looks just like the crap that comes out of osmosis blisters.
So, I'm guessing that over the last 30 years these two massive areas of polyester compound has absorbed a lot of moisture, and it'll continue to weep until I die... right?
The question then, is how do I address it. I was planning on ditching the bottom paint for good, and making her bottom nice and white with VC performance epoxy. But I'd sure hate to go through all that and have the osmosis goo breach my epoxy after a year or two.
Guess my choices are:

1) Grind all that shit out of there and start new... Really rather not, there's alot of bondo. And it'll change the boat's ride (probably improve it, which would be hard to do)
2) Sand off all the barrier coat, and allow it to do it's thing for a few weeks, in conjunction with daily denatured alcohol wipedowns.
3) Ignore it, and do three or four coats of barrier on those areas prior to
the performance epoxy...

I could post some pics later if it would help to visualize the issue.

What boat are you working on and yes I would like to see some pics
Chris

Buju

Car Bondo is one of the worst things to use on the under the water. It soaks up water. Back in the mid 80's, when blisters started to show up, a lot of guys used Bondo just to keep the cost down and because it was easy to get. They all later regretted it.

I would remove it. Sounds like an ugly job. Maybe the Capt. has the answer.

Allright Chris, pics. Boat is a '79 Sidewinder, which was a speedboat originally, but 12 of them were brought down to Islamorada new from the factory. All got custom built decks, mine was built by Chris Morejohn for Carl Navaree. Has quite a history.
Anyways the Sidewinder hull was the predecessor for the Dolphin 18, and the Shipoke... all three are a incredible riding flats boat.

Tony, yeah I know that Bondo is not up to snuff. I'm not 100% that it actually is polyester, but if it looks like a pig, smells like a pig, and weeps brown water like a pig....

looking forward to bow, bondo between outer strake and chine.

looking back

at the transom, you can see this is a thick app of this stuff. Apperently they laid a layer of glass cloth halfway through.


Obviously it'll be a bitch to grind it all out clean...already sick of working under her. I think I'll go with option #2 from above, for now. See what happens, how it dries or not, and maybe make a decision from there...
Anyone? Bueller?

Buju

What would happen if you smoothed it out and then coated it with epoxy then barrior coated it? That might be worth a shot. Do you know anyone with a gel coat peeler, you could also give that a try.

Hate to say this, but if they covered that much of the hull with it, there must have been a problem with the hull and they tried bondo to try and fix it. Maybe it was covered in blisters.

Hate to say this, but if they covered that much of the hull with it, there must have been a problem with the hull and they tried bondo to try and fix it. Maybe it was covered in blisters.

Nah... It was done when the hull was brand new. I've only ever seen 2 of the other 12 Sidewinders made into flats boats, one of em had the same thing, I'm guessing that Chris Morejohn was responsible. He was one of the three founders, and the designer of/for Hells Bay Boatworks skiffs. He also designed a class of sailing vessel (sharpie) with remarkable shallow draft capabilities, a 40'er drafts only 27"... and they successfully compete in offshore regattas.

Back to the reason for the bondo... lifting strakes and hard chines are very beneficial in producing a soft ride, as any Bertram owner knows.

BUT, when waves slap against a hull, the slap, noise, and vibration is significantly magnified when the amorphous liquid encounters a sharp angle, like a strake or chine... as anyone whos spent the night in a Bertram V-berth knows.
Normally this is of no concern... But when the boat is being used to stalk the worlds wariest bonefish in 12" of water, every slap is like a bomb going off, and real counterproductive.
So, what Chris attempted to do was minimize the sharp angles on the majority of the skiff's waterline, but in doing so no doubt made the already wet boat design, much wetter. Thus the bigass sprayrails... and oh boy do those sprayrails make some hull slap. So yeah, kinda good, progressive idea but ultimately no cigar.

I thought about a remover, or a power planer. I'll probably go that route if I need to remove it. But after just a few days it's sweating a lot less, so I'm hopefull that I'll be able to encapsulate it.

Very open to a schedule to coat it. Was thinking:

1) thinned coat of epoxy resin
2) light application of fairing compound to even out sander gouges, etc.
3) coat of epoxy resin
4) coat of epoxy barrier
5) coat of epoxy barrier on entire hull

Or should I maybe try to put a layer of cloth over it? Without flipping the hull, that'd be a good dumb and dumber routine...