Delamination?

[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

[dheaslip]

One more thing.... I was just reading some other posts and someone mentioned lightning (with regards to blistering). This boat was struck by lightning a few years ago. I'm not sure if that' relevant or not.

Regards
David

[delmarrey]

Lighting will affect metal thruhull's but not fiberglass except maybe around the thruhull's. The late 60's up thru the mid 70's were bad years for bad resin, which allowed blistering.

Your pictures don't look like blistering but more like delamination. Personally. I would strip off everything that's loose, fill in the voids with glass/epoxy, fair in and lay over a couple sheets of glass/epoxy, then put on a barrier coat of epoxy.

[Hampus]

I agree. Regarding lightning though. The lightning always takes the path of less resistans, as do we all If there eas lots of blisters and lots of moist in the hull, this could be affected by the lightning, dependeing on which route it took. Even very little water in the hull that is suddenly heated to expand should be able to cause delamination. I guess the shrouds are bolted in the hull along the sides?

Good luck to you!

/Hampus

[Robertcateran]

Originally Posted by delmarrey

Lighting will affect metal thruhull's but not fiberglass except maybe around the thruhull's. The late 60's up thru the mid 70's were bad years for bad resin, which allowed blistering.

Your pictures don't look like blistering but more like delamination. Personally. I would strip off everything that's loose, fill in the voids with glass/epoxy, fair in and lay over a couple sheets of glass/epoxy, then put on a barrier coat of epoxy.

Definitely before cruising with family. I would also check how well the keel is stuck on and the rudder is stuck together. I wouldn't discount the lightning entirely but morelikely a bad batch of resin

[amarinesurveyor]

Looks to me like not enough resin used in the lay-up, something I've seen on other Gulfstars also. It is from poor lay-up. The peeling layers should be removed and you should definately replace whatever layers are removed. Having the proper hull thickness is imperative for the structure, it is NOT cosmetic.
Lightning will not cause this kind of damage, but it can blow holes in a hull, sometimes large and sometimes small. Your hull condition is definately from dry lay-up and came from the factory like that. Good luck with the project.
Brian

[clockwork orange]

When a typical fiberglass boat is built it is laid up in a female mold from the outside in,it is indeed laid up in a number of different steps and the timing of each step is critical.
Step 1, apply the gelcoat to the correct mil thickness and allow to cure.
Step 2, apply a skin coat of chopped strand mat,this is a fairly resin rich layer and much care is taken to ensure there are as few bubbles as possible.
It is imperative that this layer is applied at the correct stage of gelcoat cure,ie,tacky to the touch so that you get a good chemical bond.
Step 3, proceed with the rest of the layup.
Step 3 is possibly where your problem lies, if too long of a time is allowed between steps 2 and 3 it becomes a secondary bonding situation rather than a chemical one and a delam is not unlikley.There are other stops and starts throughout the layup to allow exotherm to dissipate and/or core to be installed and the timing is very important but not always followed.
You could probably remove the skin coat and not necessarily replace it if the rest of the laminate is substantial enough,as it is only there because the boat is built in female molds with polyester resin and gelcoat, it really isnt there for strength although it does of course add some stiffness due to bulk.
Steve.

[camaraderie]

This could be due to the blisters, osmosis causing delam, or poor initial layup technique or wetout ...most likely some combination of the above.
Hard to tell from the pix but the solution is to peel down to solid laminate, dry out the boat, replace missing laminate layers to original thickness using epoxy, fair and epoxy barrier coat the new bottom and finally add bottom paint.

A huge job. Hope you got a very good deal on the boat...good luck!

[peterroach]

If you run your hand over the hull do you feel small glass shards? They would make you itch just like fiberglass cloth or insulation. If you do post it here and send me a private message.

[Bash]

Now is the time to hire the surveyor you should have hired before you bought the boat. A good surveyor can not only tell you what caused the problem, but what's going to be required to fix it. One of the things you need to find out is whether there's any other delamination that you're not presently seeing.

[maxingout]

This could be a "dry layup" in which the fiberglass cloth was not fully saturated with resin during the build. I would remove everything that is delaminated. Then I would tap out the hull with a phenolic hammer to detect any additional hidden delamination. I would not sail offshore in a boat like this without a major hull repair. The cracks in the bottom and the fiberglass strands in the ground out blisters look like a dry layup. I would take it all down until I get to good glass. Then fix it with glass and epoxy.

[Celestialsailor]

I'm wondering is a standard peel for blisters might do the trick and re-lay up with epoxy and X-mat. It would certainly be stronger than polyester.

[avazquez]

Just Fix The blisters with fiberglass cloth and epoxy resin and go sailing. If you think about them to much it will drive you crazy. Nobody seems to have the right answer or a permanent fix. JUST SAIL UNTIL NEXT HAULOUT.

[amarinesurveyor]

Originally Posted by avazquez

Just Fix The blisters with fiberglass cloth and epoxy resin and go sailing. If you think about them to much it will drive you crazy. Nobody seems to have the right answer or a permanent fix. JUST SAIL UNTIL NEXT HAULOUT.

That is NOT just blisters! It is a much more serious problem that needs to be addressed. See my previous post.

[dheaslip]

Thank you all for your answers - you've certainly given me plently to think about.

Of course we used a registered and experienced surveyor prior to buying the boat, but there was so much paint on the hull that it was impossible for the surveyor to detect it. In fact we couldn't even spot the delamination until we'd removed the paint & gelcoat and the hull had been out of the water for over a month and started to really dry out. We have to wonder if the previous owner intentionally left he hull paint sick to stop us discovering the problem......

I've asked the yard to go ahead and remove the loose layer, then we'll let it dry out more before building it back up again.

If anyone has any specific suggestions on things we must do in this process, please fell free to share your opinion. I don't want to spend all this money and then find out we did it all wrong!!

Thanks
David