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Is fiberglassing a wooden hull a good, bad or indifferent thing? I'd think it would keep the water out, but then I would also promote a lot of rot, and make rot harder to repair. Drying out the boat, it seems, would help fight rot, but wouldn't that shrink and loosen the boards, and generally weaken the boat?
 

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Bombay Explorer 44
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If you are talking about an old wooden carvel boat. Glassing the hull is a last ditch effort to get a few more years sailing. Accelerates the rot though.

On a new wooden boat where the strips are saturated with epoxy as they are edge nailed then glassed that is a different story.
 

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Corsair 24
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dont do it!
 

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My first boat was a wood Sabot that had been FG'ed , didn't slow the leaking a bit and made it incredibly heavy. It was done quite a bit in the sixties on various boats with the same results.
 

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Thanks, Folks. That's what I thought. I've been seeing these rather nice old boats that had been glassed, and wondered what good that did in the long run.
 

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Yeah, Especially around the base of the centerboard trunk, which was frequently a source of persistent hard to stop leaks in wood dinghys, 'course that's the low spot too so it's almost always wet in an open boat.
 

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There's fiberglassing, and there's fiberglassing. You might research the c-flex method (sea -flex?), and the Allan Vaitses method.
Simply applying fiberglass over an old wood hull is not likely to be successful in the long run.
 

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cruising all I can
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though not a fan of the idea.
I see many deadrise wooden boats in the Chesapeake that get glasses. it seems a common practice to do so.
I wouldn't.
 

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I had a glassed wood boat. If the boat starts dry it can work well - mine was tight and very solid at 60+ years. That boat was bulletproof - I really abused it.
 

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I had a glassed wood boat. If the boat starts dry it can work well - mine was tight and very solid at 60+ years. That boat was bulletproof - I really abused it.
I've always thought that if you were going to try that, or even something like the West System, the only way to make it work, is to have the patience, to completely dry the boat out, and the patience to make sure you completely encapsulate it after it is dry, inside and out. And, that you accept and understand and plan for, the likely weight increase.

It seems like that hasn't been the way it went with most of the wooden boats I have seen people try and fiberglass or coat with resin in some other way.
 

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I know a few people who have done it, some commercial boats and some recreational. It works very well only when the basic premise is to create a new fg hull using the old hull as a form. The glass has to be laid up very thick and attached with bronze ring nails to the existing hull after the first couple of layers. As long as the original structure is sound, the result is essentially a new, dry hull that will last as long as a new fiberglass hull. Rot is not a major issue because the hull is dry afterward. The best way to accomplish a job like this is to sink the boat and turn it over, lift it out upside down so that gravity is working with you doing the glass layup. Otherwise it is much more difficult. Weight actually stays about the same because the wood is now dry.
 

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I've always thought that if you were going to try that, or even something like the West System, the only way to make it work, is to have the patience, to completely dry the boat out, and the patience to make sure you completely encapsulate it after it is dry, inside and out. And, that you accept and understand and plan for, the likely weight increase.
I unfortunately never met the previous owner/builder - his widow gave me the boat. The boat was converted from a lifeboat, which was apparently a common way to build a pocket cruiser in the 40s and 50s. But as far as I know, his original plan was for the whole boat to be glassed, and he started with the lifeboat hull bone dry.

He was a German and one heck of an engineer. And he wasn't worried about the boat being heavy. It was also a heck of a lot stronger than any all-GRP boat will ever be.

I'm not suggesting it's always a good idea, or even often a good idea. But it certainly can be done and done well.
 

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Old as Dirt!
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Is fiberglassing a wooden hull a good, bad or indifferent thing? I'd think it would keep the water out, but then I would also promote a lot of rot, and make rot harder to repair. Drying out the boat, it seems, would help fight rot, but wouldn't that shrink and loosen the boards, and generally weaken the boat?
Our first "real" sailboat was a 1957 era home built plywood Thunderbird 26, designed by Ben Seaborn. The exterior of the hull was glassed as part of the build method and many of these boats are still sailing and perform very well (and some are still building them!). With glass on only one side of the timber, there usually isn't much difficulty. Fully encapsulating the wood, however, is another matter as evidenced by the numerous discussions of "wet/rotted" deck cores.

FWIW...
 

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aaaah those thunderbirds...they were built that way though!

for most wooden boats out there its not worth it...fix it the right way, the planking or caulking or whatever and replace wood where needed...glassing over especially under the water is a recipe for disaster

on our old h28 we fixed a garboard leak and also replaced the wooden stuffing box and completely eliminated the big leaks...the decks were surprisingly dry for a wood boat...again teack over ply.

planking and cotton caulking I did all the time anytime we hauled out...

usually its the caulking that gives first(depending on planking method, carvel for mine but double diagonal) and what I did was use old method with new

I used cotton string but drenched it in caulking forget if what it was either 5200 or some other stuff...then traditionally smashed it into the gaps between the planks like in old days...finally syringed a bead on top of that and that did it...

anywhoo

I have no idea these days but getting wooden boats fixed especially while crusiing is hard but can be done...

its for the love of boat that you go cruising or sailing on a wooden boat...I miss it sometimes for sure

anywhoo
 
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Once known as Hartley18
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Is fiberglassing a wooden hull a good, bad or indifferent thing? I'd think it would keep the water out, but then I would also promote a lot of rot, and make rot harder to repair. Drying out the boat, it seems, would help fight rot, but wouldn't that shrink and loosen the boards, and generally weaken the boat?
If it's conventionally carvel-planked it's generally a bad thing.. and done to add a few more years to the life of the boat. IMHO, it's only really worthwhile for vessels of historic significance (where repair cost isn't as important as keeping the boat afloat).

Of course to work at all the hull needs to be completely dried out otherwise the 'glass won't adhere properly and could simply fall right off (yes, I've seen that happen!)... but the biggest problems come later on if any water at all is allowed inside through deck leaks, over-active stern glands, hitting anything or worse - rain. This is because it's the natural swelling of the timber that keeps a wooden boat 'leak-tight', but if one side is held immovable by a fibreglass sheath, the force of the expanding (damp) timber and general movement in heavy weather can shear the planking along inside of the sheathing allowing moisture to penetrate between the sheath and the hull, rotting the boat from the outside in. Eventually all that is left is a roughly boat-shaped fibreglass 'bag' containing a pile of rotten timber - a sorry sight indeed!

With a sheathed hull, it is also very difficult to detect rot occurring since the planking appears quite sound on the inside right to the end and once 'sponginess' in the sheath is detected on the outside (eg. during an annual haul-out) the damage is usually too extensive to be worth fixing.


Sheathing usually isn't a problem with plywood yachts though, because (a) plywood is made of layered veneers, equally strong in different directions, which doesn't shrink/expand in the way timber planks do and (b) for simplicity of build there is usually only one or two hull joins (seams) which are held rigid by design.
 

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The way I remember it the difference is primarily in the thickness. One guy that had pretty good success dried out the boat then put on enough fiberglass that the wood was no longer necessary even though it was left in.

Just a thin skin of glass would not hold up.
 

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The way I remember it the difference is primarily in the thickness. One guy that had pretty good success dried out the boat then put on enough fiberglass that the wood was no longer necessary even though it was left in.

Just a thin skin of glass would not hold up.
If you were going to do that, you might as well take all the timber out and then bolt the deck back on.. :D
 

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I think a lot of the failures you hear about from the sixties and seventies were because they were done with polyester resin. I think you have a pretty good chance of it working if you use epoxy resin and make it thick enough.
 

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It would sure be nice to find a feasible way to save a lot of these beautiful older wooden boats before they are gone. I used to see a lot of them in yards when I lived in Maryland and there were a lot more of them around, than people willing to completely redo them in the traditional way.
 
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