Fiberglass Sheathing a 1962 Carvel Hull

[gypsie]

My boat broke its mooring and was damaged.
Insurance company wrote it off, (repair costs were higher than agreed value - because of labour), i bought it back and am now in the process of repairing it.
Thread here; http://forum.woodenboat.com/showthre...ew-Deck/page17 From about page 17 I'm dealing with the current (involuntary) issue. (Page 1 gives you some insight into the boat, age/history).

Repair includes bringing the boat back to bare wood.
First she was sand blasted, gently but with predictable (minor) consequences, and now I am in the process of sanding off the remaining paint and making her fair again.

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I want to consider sheathing her in epoxy and fiberglass.

I have been reluctant to sheath for a number of reasons, examples;
A) - the hull is sound, the planking and framing are sound, the caulking is sound. She is in general good health. (but she is aging).
B) - water ingress under the sheathing. How do i deal with areas for example around the ballast - how do i prevent water ingress and the glass working away....?
C) - Scale - am i just introducing a bloody huge job, with attendant costs, without a good reason.
D) - Won't the movement of the hull crack the glass and then - water ingress under the sheathing....? Note the hull is sound and there is no discernible movement of the planks (when she's not getting buffeted onto a beach). Caulking is good as of before sand blasting, now some of the compound is flaking out.

The Pros are fewer BUT persuasive;
i) simply protecting the boat. I must admit i lay awake nights, from about 9 months plus after haul out, worrying about worms. I've had debris catch my mooring line and knock bottom paint off - so emergency haul out for repairs below the waterline = expensive and time consuming.
ii) Longevity - I know there is a sentiment expressed in post #5 here; https://forums.ybw.com/index.php?thr...eathing.79345/, but - with a sound boat, given what we know about modern materials - this could be a reliable way of protecting this boat indefinitely. Given the positive condition of the boat - encapsulating it now could be a genuinely good thing.


Questions to start off with;
-Process for reliably sheathing the hull.
-Thickness of cloth, type, number of layers.
-Do i need to drop the ballast off? Do i glass over it too?
-Do i need to glass the inside as well ? (Who was that french dude?)

[wizbang 13]

Sheathing a carvel boat is like varnishing a cabin side... in that 90 percent of the work is in the prep.
To sheath sucessfully, the boat must be dried out..that is a year under a roof.
The hull must be stabilized and locked up....that means ripping out the existing seam compound and cotton and either gluing in splines or solid epoxy.The wide planks may want to be "kerfed" with a skilsaw blade...this is an easy enough job, but one must realize there is no going back.
A boat gets to a certain age.. there are hard questions to ask...easy to answer.

[pcford]

Just don't do it. If the boat is on its last legs and you do not have the resources to do it, you could get a few more years out of it. After that, mulch.

[gypsie]

Just don't do it. If the boat is on its last legs and you do not have the resources to do it, you could get a few more years out of it. After that, mulch.

She is a long way from mulch. Definitely not on her last legs - far from it.

[gypsie]

Sheathing a carvel boat is like varnishing a cabin side... in that 90 percent of the work is in the prep.
To sheath sucessfully, the boat must be dried out..that is a year under a roof.
The hull must be stabilized and locked up....that means ripping out the existing seam compound and cotton and either gluing in splines or solid epoxy.The wide planks may want to be "kerfed" with a skilsaw blade...this is an easy enough job, but one must realize there is no going back.
A boat gets to a certain age.. there are hard questions to ask...easy to answer.

So far, so 'not going there'.
Stabilised is not just about wood shrinking/expanding - its about movement at the seams..? Prevent cracking of the glass at the plank joins. Splines I presume, to be glued in - effectively turning the hull into a strip built hull with edge glued planks.
What you're describing to me is a radical change in the nature of the boat.

Ripping out seam compound and caulking cotton, could be; run the circular saw (kerf) along seam - set to a depth that doesn't cut the frame in two. With a 3mm thick blade, insert a 3mm spline....... That is not as much work as it feels at first blush. A baton screwed on to guide the saw.......
Would the spline have to go all the way through - or - with a 28mm plank, insert a 20mm deep spline? Or maybe just a 10mm spline all round.

[pcford]

She is a long way from mulch. Definitely not on her last legs - far from it.

Then don't do something that will likely be very bad for the boat.

[gypsie]

West system have a publication on Wooden boat restoration and repair. Section 5.1.1 page 28 concurs with Whizbang.
https://www.westsystem.com.au/produc.../publications/

Indeed - no going back.

[RFNK]

Wizbang is right, except it won't need a year to dry out. The hull must be stabilised prior to sheathing. The best way to do that is by splining. This involves having a splining blade made up for a small circular saw then running it along each seam on a batten. A spline is then glued into each seam. This is not a big job and I can help with locating a shop to make the blade.

Then you have two choices. Cold moulding or structural sheathing. Double diagonal strips of timber, sheathed, or two layers of glass. My first thought would be a moderate grade of double bias but another form of glass might be better - that's easily checked. All epoxy, of course. Seabirds are true classics. Do this properly and you'll have a great boat. I I were you, I'd use multiple layers of glass (probably 2) over a spline hull. I think this is the simplest method that will actually work. Of course the hull must be free of any rot and dry enough. Once the westerlies kick in, in another month or two, it'll be dry enough.

[RFNK]

The splining blade cuts through the seam but not into frames. To be most effective it should be a tapered blade. I tried years ago to buy one but couldn't find one. But any good saw shop can make one up. A good investment and should be easy to sell. The spline can be glued in with either epoxy or polyurethane. Poly likes moisture, epoxy doesn't.

[Peerie Maa]

If the hull is stabilised so that there is no movement in the wood at all anywhere, what does sheathing it add? You have a strong sound boat before you apply any e/glass, so why do you need to do it?

[RFNK]

If you decide to go this way, get a basic moisture meter. They are cheap and you'll be able to check the dryness of your planking over the next few weeks etc.

[RFNK]

If the hull is stabilised so that there is no movement in the wood at all anywhere, what does sheathing it add? You have a strong sound boat before you apply any e/glass, so why do you need to do it?

The fasteners are old and would be allowing moisture through. The old planking is softer and weaker. With structural sheathing, the hull will be stronger, more waterproof, antifoul will last much longer and the interior of the boat will be drier.

[RFNK]

For the record, my boat, Masina, is strip planked, edge nailed and glued, and sheathed. Built in 1975, sailed all around the world, and the hull remains virtually as new. Hull maintenance is negligible.

[Phil Y]

Mine likewise, but built in 1974 and only sailed Australian waters. My leaky deck, now replaced, has over the last few years let water into the hull and I suspect that to be the cause of some topside seams cracking as she dries out in the summers. Time will tell.

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[RFNK]

Well, happily Masina's plywood deck was also sheathed properly in 1975 and remains perfect.

[johngsandusky]

My first keelboat was a 20' sloop, built in 1961, fiberglassed in the mid seventies. I bought her in '91, sailed her year round for eight seasons and passed her on. I believe she would be sailing still if she had better fit the needs of the next owner. She was hard chined Phillipine mahogany on sawn oak frames with an iron keel. The bottom was fir plywood, only the sides were planked. The keel was not glassed, but the decks were. The guys who did it were not at all experts I think. They did slather some resin in the bilge, it flaked off. Overall the glassing was a success, the boat did not leak.

[Peerie Maa]

If the hull is stabilised so that there is no movement in the wood at all anywhere, what does sheathing it add? You have a strong sound boat before you apply any e/glass, so why do you need to do it?

The fasteners are old and would be allowing moisture through. The old planking is softer and weaker. With structural sheathing, the hull will be stronger, more waterproof, antifoul will last much longer and the interior of the boat will be drier.

If she is nail sick and the planking soft then structural sheathing with the same thickness lay up as a glass hull might be necessary. I'll give you that, but is the hull that old and decrepit?

[skaraborgcraft]

If the hull is stabilised so that there is no movement in the wood at all anywhere, what does sheathing it add? You have a strong sound boat before you apply any e/glass, so why do you need to do it?

From the OP: The Pros are fewer BUT persuasive;
i) simply protecting the boat. I must admit i lay awake nights, from about 9 months plus after haul out, worrying about worms. I've had debris catch my mooring line and knock bottom paint off - so emergency haul out for repairs below the waterline = expensive and time consuming.

[Jay Greer]

Having been around long enough to see how various miracle products work for extending the life of a vessel I have had the opportunity to see several famous and some not so famous boats and yachts undergo glass encapsulation in order to avoid having to face an epensive rebuild. Some of them were glassed by experts in glass work and some were done by amateurs. But, in all cases I have yet to see a successful outcome from this form of preservation of an entire boat! Two things usually result; either the wooden structure, of the boat moves within the sheathing and begins to crack the glass thereby creating all manner of problems. Or, the boat rots out from within the glass sheathing making it necessary to build a replica boat. Which is what is proported to have been necessary for the Nick Potter 1930 Eight Meter Yacht "Angelita". It coast a heck of a lot to save that boat after the glass job failed! I belive it was William Cannel who did the work.
Jay
http://classicyachtinfo.com/yachts/angelita/

[Wesley]

I believe fiberglass sheathing can be effective, based on the example of Speedwell of Hong Kong (http://speedwelladventures.com/speedwell.html). Glass sheathed a Vertue, with 17+ years of live-aboard trade wind world cruising since. Always listen to wizbang w.r.t. using epoxy in unconventional ways.

[Peerie Maa]

From the OP: The Pros are fewer BUT persuasive;
i) simply protecting the boat. I must admit i lay awake nights, from about 9 months plus after haul out, worrying about worms. I've had debris catch my mooring line and knock bottom paint off - so emergency haul out for repairs below the waterline = expensive and time consuming.

For that, coat the hull in nylon cloth set in resorcinol resin, which used to be called Cascover in the UK.

[Dody]

All this depends on many factors. There were times when people used Polyester for the sheathing. Polyester doesn't bond properly to any wood, the worse so if it was in contact with saltwater before and the salt crystals have found their home inside the wood, something destined to fail from the beginning - and many, if not most attempts, were done like this. The next problem is the natural movement of the wood in connection with humidity, it contracts and expands. Whatever is bonded to it needs to be capable to adapt to this behavior or be forced not to behave like this, otherwise failure is pre-programmed. All this is getting even worse if the boat has some kind of structural issue. Be it for example the floors beeing cracked somewhere, the hull needing a re-fastening-job or whatever. Should this be the case, the planks will always be on the move and there is no way sheathing could be doing any good. To the contrary, the sheathing will crack, water gets in and will definitely start it's destructive work.

Contrary to that, Tonga, my ketch, was built and launched with a similar kind of built: she is planked (never built to go in the water like this, so there is gaps between the planks), then a diagonal layer of ply on top of the planks and fibreglass on top of this, something that is very strong, watertight and never gave any trouble. Tonga having her 60th birthday on the 3rd of July this year means I have to re-fasten her. As I said before, Polyester doesn't bond well to wood and Tonga's outside was done in Polyester, so the job of taking it all off is pretty easy. Once I've re-fastened her I'll do the same system again: plywood-strips diagonal on the planks and bi-diagonal fibreglass - with Epoxy this time!! - on top.

But, honestly, why would you like to be sheathing a healthy boat? It doesn't make sense to me!

[Rumars]

I see two things to watch out for, moisture content and wood species. The planking may dry out pretty fast, but the keel, deadwood and stem are much thicker and will take much longer to stabilize at 12%. You must also ensure that the turpentine wood works well with your chosen epoxy. Sheating on wet or difficult to glue wood is pointless.

[Phil Y]

Shipworms are voracious on parts of the east coast aren't they? I'd be lying awake too. But I'd certainly be in 2 minds about sheathing an older carvel hull. Both Rick's and my boat are strip planked, edge nailed and sheathed from new. Big job anyway you do it. A layer of cold molding as Rick suggests is probably ideal. I think Rick has an interest in an old fishing boat turned dayboat which has been sheathed. I assume that's going well?

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[wizbang 13]

Picture repairing a carvel boat that has been cold molded, a repair of an original plank that went rotton,despite ones best efforts.
The cold molding is in the way, it must be chopped and ground off, beyond the plank that needs repair or replaced whatever, but now the freakin cold molding must be replaced. Now think about the same job on a boat that has 2 layers of 10 oz fg.
The boat with the fg will be far easier to repair, and that is assuming one can even GET the wood veneers for the cold molding without a lot of fancy dance moves.
The cold molding without some glass or dynel on it is still sussep...suxpect... supcept... it is easy prey for worms still.
I don't get the cold molding thing... it is SOOOOOOO 1980's.

[gypsie]

There seems to be a good argument against sheathing an unsound hull, and the other end seems to be don't sheath a sound hull.
Arguments for because it worked so well, arguments against because it was disasterous.... (Disasterous = bad workmanship usually).

Right now the ROI of the amount of work/expense involved (high), plus to the risk of effing it up (exists), on a hull that doesn't really need it - is not compelling.
Having said that - it seems, if yer gonna do it, then do it when the boat is sound. Stitch in time and all that.

This will also be a one handed job - me on my lonesome, with maybe a borrowed pair of hands every now and then. My 14yo son would help (for pocket money), but its not a skilled help.

Planking is Oregon (Douglas Fir), fastners are sound, copper rivet/rove. Some plugs are thin, but only over some monel screws so far. Movement in the hull is minimal - glued splines would stiffen that right up.


According to West - kerfs should be parallel (not tapered) about 4.5mm thick but the spline should be tapered 10°. I imagine to allow space for glue to live on the inside edge of the spline. Kerf should end just shy of the inside seam - to contain the glue.
Spline blade = thick rip saw blade?

[RFNK]

I'm not suggesting cold moulding. I said it's an option. It's not what I would do.

[RFNK]

If she is nail sick and the planking soft then structural sheathing with the same thickness lay up as a glass hull might be necessary. I'll give you that, but is the hull that old and decrepit?

The point is that hulls get to the stage where such problems are beginning to emerge. If they can be properly protected and reinforced at this point then they don't deteriorate to such an extent. If the deterioration is already so advanced then an approach like Vaitses' method can be the only alternative - a fibreglass hull is virtually created around the old wooden hull. Gypsie's boat doesn't need that now and, if it's sheathed properly now, it never will.

[RFNK]

Anyway, those of us who've put a lot of work into restoring old boats and are enjoying all the advantages of properly protected hulls and decks, don't really care about should we or shouldn't we debates that never end and I'm not going to engage in yet another pointless argument. So, Gypsie, let us know if you decide to go ahead with it, and I'll be happy to share ideas gleaned from contacts who actually know what they're talking about.

[Hallam]

I like the idea of stripping back to bare timber and giving it a few coats of clear penetrating epoxy as a primer then doing a two pack epoxy filler undercoat and finish with 2 pack polyurethane. I use Norglass when i did this to Warana and have been happy with the results. Thull built in 56 from Iroko is still in great condition. Regarding splining maybe spline above the waterline and caulk below.
I dont feel good about fiberglassing the hull. I did see one successful job using dynal sheathing on a Harrison Butler calerytop hull in Hastinngs Vic.

[Small boats rock]

The biggest issue with a job like this must be the question of whether or not hull movement can be minimised enough (hopefully the question of adequate bonding is taken care of by the use of epoxy not polyester). Obviously if the moisture content of the planking is stabilised, and all locked together with splines, this will go a long way to dealing with movement... but still remaining is a traditional internal structure. Do you have anything in mind for the internal structure or is the consideration strictly limited to dealing with the planking?

[gypsie]

Anyway, those of us who've put a lot of work into restoring old boats and are enjoying all the advantages of properly protected hulls and decks, don't really care about should we or shouldn't we debates that never end and I'm not going to engage in yet another pointless argument. So, Gypsie, let us know if you decide to go ahead with it, and I'll be happy to share ideas gleaned from contacts who actually know what they're talking about.

I've got a whole bunch of sanding to do no matter what - probably weeks of it. Plenty of time to get to know the hull intimately.
I'll continue to mull it over.

Sincere gratitude to all who've contributed to this thread so far.

[gypsie]

This looks like the tool for the kerf.

https://www.makita.com.au/building-c...rcular-saw-kit

Light, battery powered. Wonder what the kerf is, would need a bigger one anyway. 15mm bore......

[Andrew Donald]

I’ve got its 18v brother and kerf is only about 2mm. I wonder if you bolt two blades on? Battery might not be up to it though.

[gypsie]

i checked out the 18v version, the Makita guy reckons even the 18v battery may not be up to what i need to do.
He's arguing that a light router is the way to go, and thinks the 18v machine could take 2 blades side by side.