Delamination Issues

[dheaslip]

Hello

I recently purchased a 1982 '68 Gulfstar Sailmaster and I have some issues with the hull. When we hauled it out for survey we noticed a good number of blisters and after purchase we put it on the hard to repair them. After grinding off all the paint and gel coat we noticed some unusual lines in the fiberglass. We ground out the blisters and have been letting the hull dry for the last two months, but we keep noticing that more and more "dry" areas are appearing. It's starting to look like the hull has a complete layer of fiberglass that is not adhering well to the layer beneath. In fact, you call pull the fiberglass away without too much trouble. The previous owner admited (after the sale) that they'd had layers of fiberglass peel off the hull in heavy weather a couple of years ago, but in their opinion it was "no big dea!"

I'm curious to find out about this layer, because it looks like a) it was applied after the hull was taken out of the mold, or b) a few layers were laid down in the mold and them they resumed the rest of the hull later. I've tried to contact Lazzara Yachts (who were the original designers back in the 80's) but no one there will talk with me. My surveyor is running out of ideas.... We're not sure if we can just remove the layer (if it is just cosmetic) of if we need to remove it completely and re-glass the entire hull.

In the photo you can also see a line in the fiberglass that is identical both sides of the hull and looks like a join the the glass. I've also posted a close-up of this. I've never seen anything like it before.

Does anyone have any idea what's going on here? I'm planning to take my family cruising and need to know if we have a significant structural issue here, or if the layer is just cosmetic.

Regards
David

[rasorinc]

My guess would be a layer of mis-mixed epoxy that will not adhere. In any event those pictures show a real problem. You will not be able to just cover this layer with another layer as you will have the same problem so the bad layer has to come off. You might try a patch of glass over a small area and let it cure then try to pull it off and if you can then you have your answer. You might try to find out what epoxy or other resin was used or have an analysis done on a piece of that layer. Insurance companies shold have info on who does that type of testing.

[Itchy&Scratchy]

Just to be sure I would have that boat gritblasted up to the waterline and sheath in epoxy and then apply gelshield before antifouling.

Its probably had its first layers of laminate behind the gelcoat applied on a Friday and not sufficiently sanded down before continuing the lamination on the Monday. A lot of people think its ok just to wash the laminate with acetone befor continuing the lamination but in my opinion this is not sufficent to form a decent bond before the first set of laminating and the following laminate layers.

You might need to leave the boat to dry out properly, see if you can get a moisture test done on the laminate.
good luck
regards

Justin

[glasscrafters]

Yeah it looks like a layer didn't adhere to the other during building. You need to- at the very least- remove the glass that is not bonded and lay it up again. But, if there is any moisture or other contaminates you'll be wasting your time, so be sure you have a good surface to bond to. Good luck!

[TeddyDiver]

Originally Posted by rasorinc

You might try to find out what epoxy or other resin was used or have an analysis done on a piece of that layer..

I don't believe -68 model glassfiber boat even seen a drop of epoxy.. However taking a piece of and torching it will make it sure.. poly will burn well after catching fire, epoxy don't..