Loss of Gel Coat on Hull

[Hooksetter]

During the survey for the purchase of a 48' 2005 fiberglass trawler, discovered that the paint system had failed, and there were blisters throughout. Current owner has hired a reputible yard to repair. Soda blast has revealed that the gel coat is essentially gone. Yard is applying the West System to repair, and will apply two barrier coats and repaint.

Does this cause anyone serious concerns with moving ahead with the purchase after repairs?

Thanks

 

[Comodave]

Our last boat had been peeled and rebuilt due to blisters. They take essentially a planer and take off a thickness of the hull fiberglass until they get to stable glass. Then they reapply fiberglass to build it back up. Epoxy is the preferred resin as it is more waterproof. Then they did a barrier coat with epoxy paint. Then new bottom paint. I had no more blisters while I owned the boat. The work was done in Virginia and the owner of the marina where the boat was at said the yard that did the work was the best in the area. I guess that it depends on the quality of the work on how long it will last. My concern would be that since the seller is paying for the work he may not really care how well it will be done because he won’t be the owner for long. Is he paying for a top notch job or just a get by until it is sold job? Not sure how to find out. This work is extremely expensive if done correctly.

 

[Hooksetter]

Our last boat had been peeled and rebuilt due to blisters. They take essentially a planer and take off a thickness of the hull fiberglass until they get to stable glass. Then they reapply fiberglass to build it back up. Epoxy is the preferred resin as it is more waterproof. Then they did a barrier coat with epoxy paint. Then new bottom paint. I had no more blisters while I owned the boat. The work was done in Virginia and the owner of the marina where the boat was at said the yard that did the work was the best in the area. I guess that it depends on the quality of the work on how long it will last. My concern would be that since the seller is paying for the work he may not really care how well it will be done because he won’t be the owner for long. Is he paying for a top notch job or just a get by until it is sold job? Not sure how to find out. This work is extremely expensive if done correctly.

Thanks, this is helpful. They didn't have to use a planer and feel the blast got to adequate substrate. Yard Manager seems genuine and says the owner has authorized a proper repair.

 

[sean9c]

If it's the whole boat, on a boat that size, a repaint like that costs north of $100k. Quite the seller.

 

[Endeavor GB 32]

Run, don't walk.

 

[O C Diver]

During the survey for the purchase of a 48' 2005 fiberglass trawler, discovered that the paint system had failed, and there were blisters throughout. Current owner has hired a reputible yard to repair. Soda blast has revealed that the gel coat is essentially gone. Yard is applying the West System to repair, and will apply two barrier coats and repaint.

Does this cause anyone serious concerns with moving ahead with the purchase after repairs?

Thanks

As mentioned by another, is this the whole boat or below the waterline?

If it's below the waterline only, what faith do you have that the entire boat won't have this problem?

Typically the hull of a traditional boat is molded in two pieces. After the molding process, the two pieces are joined. Typically the mold process starts by spraying gel coat in the mold and then building it up with fiberglass. After the two pieces come out of the mold, the hull is joined. Once the boat is mostly complete, the boat gets a final gel coat. What is important to understand is that the original gel coat first sprayed in the hull is what is against the fiberglass. Whether it's the first layer that failed or the top coat, that process could occur over your entire boat.

This occurred on my boat. The 1st layer was good; the final layer was poorly prepared. The entire second layer had to be removed. I new this going in, and had priced in an entire paint job.

One last point. Barrier coat is based on thickness. Instead of doing one or two thick coats, my boat received 4 average coats with alternating colors between white and gray. When you alternate colors, you can clearly see any areas you missed.

If only the bottom is involved what insurance do you have that the entire boat won't eventually need to be redone? I would walk away.

Below is the link to the thread on my refit. It covers most of the gel coat failure in addition to other things. There are some good pictures of barrier coating the bottom:

My Short Haul Refit

For those who aren't familiar with the term "Short Haul", it basically means your boat is being lifted out of the water (usually by a travel lift) for a short period of time to do a repair, and then put back in. The boat isn't removed from the travel lift slings. As my boat enters the 9th month...

www.trawlerforum.com

Ted

 

[Hooksetter]

I appreciate all the comments. We are only talking below the waterline. I've attached a photo. I don't believe they arena instances where they have to reapply glass.

 

[Comodave]

Back in the day Uniflite built boats with a flame retardant resin like they did for the river boats for use in Viet Nam. They would blister everywhere, absolutely everywhere. I haven’t seen other boats have blisters above the waterline, but I suppose it could happen.

 

[BDalt]

During the survey for the purchase of a 48' 2005 fiberglass trawler, discovered that the paint system had failed, and there were blisters throughout. Current owner has hired a reputible yard to repair. Soda blast has revealed that the gel coat is essentially gone. Yard is applying the West System to repair, and will apply two barrier coats and repaint.

Does this cause anyone serious concerns with moving ahead with the purchase after repairs?

Thanks

Blistering is a process that works on the fiberglass under the gelcoat and does not usually lift a majority of the gelcoat. The blasting opens up the blisters, leaving the glass exposed and the gelcoat not lifted by blistering on the boat. If your gelcoat was "essentially gone", it suggests aggressive blasting which would also have eroded glass in the blistered sites. Some erosion might not be a bad thing as it assures a clean 'wound', free of the acid causing the erosion. In any case the real trick to restoring the bottom is a careful examination of blister pits and a decision on which should get fiberglass patching, versus thickened resin filler. Patching is best done by grinder prepping a nice shallow scallop, and filling that with increasing patch sizes of glass. Before that though, use a lager orbital sander to remove any gelcoat that would hinder filling or patching. When surface prep and patching is satisfactory, apply fairing compound to bring the surface back to a prefect surface. You should not need to apply a new layer of glass to the whole bottom, but the possibly over aggressive blasting needs to be considered. Consider using the "Copper Coat" system to finish the bottom with an epoxy instead of an ablative paint, which pollutes. The barrier coat epoxy recommended with the Copper Coat is a bit tricky and must be fair before applying the Copper Coat(s).

 

[psneeld]

The main problem may be hydrolysis of laminates further into the hull when major blistering is an issue.

Really no way to tell if you have serious hydrolysis delamination/resin loss of laminates without major grinding below the biggest blisters or random hull coring. Tapping didn't really discover the problems with my hull, a 1988 40" Albin.

I wound up grinding all the gel and first layer of matt off my boat, and let it dry for the winter months. In some spots I had to remove over 6 layers of roving and matt (approx 1/2 inch deep) were the laminate was saturated with water. In the spring I covered the entire bottom with 6oz glass, then the Interlux Interprotect system and bottom paint.

This is all very expensive unless DIY. I only spent a few thousand on materials but a pro job may cost $40,000-$60000. And that is just an inflation adjusted cost over what it usually cost 15 years ago when I was researching.

When I sold the boat a few years back, it had zero blisters on its bottom (at least I remember it being reported so).

So running away is a "maybe" recommendation for me. If the bottom is done well, it is better than new. Not many do it right as they only think blisters and the hull is still possibly full of water. If the bottom is peeled/ground down to a completely dry foundation, properly faired, at least a thin layer of epoxy laid down, then barrier coated before painting....I may consider the purchase.

Again I warn about it not being thoroughly peeled/ground, dried and sealed. NOT many yards I have ever worked at or had used would know what to do.... "well".

 

[mvweebles]

@Comodave describes a process where the hull is stripped then built up with new layers of fiberglass. A second, less expensive process (but still expensive) is what it sounds like the OP described - remove gelcoat and fix each individual blister, then barrier coat. It's a pretty common procedure.

Topside blisters are very uncommon. Uniflite was mentioned above. Valiant sailboats had similar issues. Some Willard's did too. Up in the California Delta I bumped into a guy with a 32-foot Uniflite fishing boat that looked like an inverted golf ball. He was delighted because he couldn't have afforded the boat otherwise and he was pretty sure the fish didn't notice.

There is some risk that a few blisters will reappear over time. Repair them as they come up. Below waterline blisters are common. If you can't live with blisters, suggest a different material. Wooden boats don't blister.....

Peter

 

[lwarden]

It would be helpful to get some more closeup pictures of the issue.

 

[Gdavid]

During the survey for the purchase of a 48' 2005 fiberglass trawler, discovered that the paint system had failed, and there were blisters throughout. Current owner has hired a reputible yard to repair. Soda blast has revealed that the gel coat is essentially gone. Yard is applying the West System to repair, and will apply two barrier coats and repaint.

Does this cause anyone serious concerns with moving ahead with the purchase after repairs?

Thanks

Gelcoat is surprisingly porous and does not provide the best protection to the fiberglass laminate. Gelcoat uses polyester resin for the base which is inferior to both vinylester and epoxy for osmotic protection. This is why many higher end fiberglass builders lay up the hull in vinylester or at least the first layers before using polyester resin for the laminate construction. Epoxy is the best, but also very expensive and rare for a complete layup. When applied properly, a barrier coat will provide much better protection, there is a minimum thickness that every manufacturer will specify. 2 heavy coats may get you to that thickness, but it is more important to specify the thickness than the number of coats. There aren't too many manufacturers of these products, so the research is pretty easy. There are also pretty specific timelines that must be followed to ensure adequate adhesion and curing between coats, the barrier is an epoxy product, and each coat needs enough time at the right temperature to start curing, but the next coat needs to be applied within a certain time to adhere to the previous coat.

I would calculate wetted surface area of the hull and use the manufacturers guidance for the coverage to figure out how many gallons are required and make sure that amount goes onto the boat. I would try to be around when it is being done to ensure the coverage is properly done. It would be in your interest to buy the additional product to ensure the job is done right. Barrier coat for that boat is probably $800-$1000 (excluding labor and shop materials), which is cheap compared to the $5-10K cost to soda blast the old-failed gelcoat/laminate away. I would much rather spend a little more to avoid doing the job again.

 

[JackConnick]

Generally after stripping off the gel coat, the boat needs to sit in warm environment and dry out for quite a while. That could be hard in winter. They need to be doing moisture tests along the way. Otherwise you're just sealing in water in the glass and the blisters will reappear. Be sure to ask about moisture tests.

 

[Gdavid]

Generally after stripping off the gel coat, the boat needs to sit in warm environment and dry out for quite a while. That could be hard in winter. They need to be doing moisture tests along the way. Otherwise you're just sealing in water in the glass and the blisters will reappear. Be sure to ask about moisture tests.

I had always heard the same recommendation, and I shared it years ago when someone made a post about having barrier coating done, then Steve D'Antonio commented on the same thread that drying out a fiberglass boat was an old wive's tale (or something to that effect). I don't see how it could hurt, at the very least I would wipe down heavily with a lot of acetone to help ensure a clean and dry surface.

edit: I had to go back and find that thread, I welcome Steve's knowledge on this stuff.

To soda blast or not?

I’m literally in the same boat! Although a sailboat. I also work in the Marine Industry…here’s what I know: Nothing beats a Soda/Walnut blast to remove old paint. If it’s built up to the point of peeling off, sanding will take forever, the cost of pads will be very high, the chances of hull...

www.trawlerforum.com

 

[psneeld]

I had always heard the same recommendation, and I shared it years ago when someone made a post about having barrier coating done, then Steve D'Antonio commented on the same thread that drying out a fiberglass boat was an old wive's tale (or something to that effect). I don't see how it could hurt, at the very least I would wipe down heavily with a lot of acetone to help ensure a clean and dry surface.

edit: I had to go back and find that thread, I welcome Steve's knowledge on this stuff.

To soda blast or not?

I’m literally in the same boat! Although a sailboat. I also work in the Marine Industry…here’s what I know: Nothing beats a Soda/Walnut blast to remove old paint. If it’s built up to the point of peeling off, sanding will take forever, the cost of pads will be very high, the chances of hull...

www.trawlerforum.com

I can attest that once you stril/grind to dry laminate, you can almost be positive it is dry by look and feel... but niw having used a moisture meter to verify.

Dry with a gel coat on is the bjg mistake as it really won't. Strip/grind through the wet stuff and drying coukd be considered uneccesary.

 

[Hooksetter]

I truly appreciate all the comments. Attached are some additional photos as requested.

 

[lwarden]

Really hard to see from these pictures. They would need to be very up-close of several areas to get a better feel for what's going on.

 

[Hooksetter]

Really hard to see from these pictures. They would need to be very up-close of several areas to get a better feel for what's going on.

Unfortunately the boat is 800 miles away. I've been promised some photos of repairs tomorrow. I'll ask for some close-ups and share when I have them. Thanks

 

[BruceK]

Pics are best taken right after the boat comes out of the water, and looking along the surface. Though straight can show detail. The boat has been up long enough for extensive cleaning and sanding. If deep, heat application can get the nasty fluid flowing.Pics of repairs underway might be as good as it gets now. Hope they don`t need fiberglass mat to reconstruct the depressions.