Fiberglass sheathing old carvel planked boat

[Zen Zero]

My brother in law is the owner of this beautiful 80 yr old carvel built racing "gozzo" which lives in fresh water on Lago di Bolsena.

He wants to do some hull maintenance, including sheathing the hull in glassfiber and resin, which I think is a really bad idea.

"The water will get betwen the resin and the planks and will rot your boat quicker" I told him. "You should recaulk it where needed, replace any rotten planks and paint it with traditional oil paint and maybe some anti-foul."

He's not convinced, and of course, I may be wrong. I'd just consider it a minor crime against humanity to damage that boat.

Thanks.

 

[lw395]

Sheathing has a poor reputation, from the days of people doing poor jobs with polyester resin.
If done properly with epoxy resin it can be a valid course of action.
It partly depends on the state of the rest of the boat.
If it is the best way to get another 10 or 20 years use from a boat that is otherwise 'beyond economic repair', that is a different situation from damaging a boat that can be kept original.

Not something that should be done lightly, and be aware that a proper job will cost quite a lot in materials and add significant weight.
Doing a proper job will also imply a long time drying out the wood.

Also as it's a racing boat, it may be against the class rules.

 

[CAPTAIN FANTASTIC]

Nothing is wrong with covering a wooden boat with woven cloth and epoxy (ie West system) but has to be done right or you will end up with a situation where the cloth separates from the timber.

The boat has to come out to dry under controlled temperature, then cleaned degrease, etc. It is very costly to cover the boat with woven cloth (two layers) and epoxy (can not use fibre glass resin as will separate from the wood).

Timber boats has been engineered to allow movement, however, after the boat has been covered with cloth and epoxied, the wood will not flex much, which has its advantages and disadvantages. The deck would have to be done too. Overall, not an easy job, and costly, but this is the only way perhaps, to safe old wooden boats nowadays. Maintaining a wooden boat using traditional methods (oil based paints caulking etc) is a continuous never ending job, fighting a loosing battle.

 

[westernman]

If you go the sheathing route, it will have to be 100% waterproof and will have to be done inside and out. It is not just doing "some" maintenance on the hull. You have to do the whole lot.

In practice, 100% waterproof is almost impossible to achieve on an old boat. It moves too much and will open up somewhere. Once the water gets in, then the boat is finished in no time at all.

So, I would strongly recommend not to go that route at all, but stay with new planks, caulking (splines if you have to) and traditional paints (certainly no two pot stuff) and to put up with the leaks.

 

[Tranona]

Agree with much of what has been said already. It must be epoxy and cloth if he is going to do it. However to do it properly means taking the ballast keel off and stripping and drying all the planking. The internal structure must also be sound, both timbers and fastenings, and possibly epoxy coating the inside. Ideally the deck should be done as well so the timber shell is completely sealed. The enemy of sheathed boats is fresh water. If it gets into the wood, rot starts very easily because the wood cannot breathe and you end up with a rotten boat encased in an impervious shell.

Better to stay with the traditional methods and just recognise that old boats were rarely designed or built for long life, so constant maintenance and repairs to the structure are inevitable.

 

[Spuddy]

The last time I bought Classic Boat comic, several years ago, there was a feature about a yard in California which did do epoxy sheathing on old classics - successfully they claimed.
I noticed in the Greek islands that the small fishing boats of traditional design seem to be sheathed and it looks like it's lasted.
So it looks like it can be done despite me too thinking like zen zero. I still expect that the timber WILL want to move and dunno how the stresses between epoxy and planking will work out.

 

[Zen Zero]

Also as it's a racing boat, it may be against the class rules.

He doesn't race it and I don't think there are enough of them left to make a class.

I think the consensus is that it can be done, but properly, with epoxy and a great deal of care; otherwise it's an extremely bad idea.

I went and joined Classic Boat (didn't that used to be here?) to ask the same question,, but it had already been asked / answered http://www.classicboat.co.uk/forums/showthread.php?t=119997&highlight=carvel+sheath

As usual, thanks for the kind and helpful advice.

 

[panthablue]

I'm against it. As some of the contributors have said, if it's done well, then fine.

the only trouble is, you don't know if its OK until a few few seasons soft spots develop in the skin. Then you are into major drying out and patching.

the other downside is the weight. In the picture the boat is high on her marks, and by the way looks beautiful, but a skin of fibreglass and a ton of epoxy will add quite weight which will lower her down, and slow her down.

 

[Quandary]

I'm against it. As some of the contributors have said, if it's done well, then fine.

the only trouble is, you don't know if its OK until a few few seasons soft spots develop in the skin. Then you are into major drying out and patching.

the other downside is the weight. In the picture the boat is high on her marks, and by the way looks beautiful, but a skin of fibreglass and a ton of epoxy will add quite weight which will lower her down, and slow her down.

I dispute the idea that adding fibreglass and resin to the outside of the hull will add significant weight, below the waterline the displacement will increase pro rata and the weight increase is only the difference between the specific gravity of the materials used and the water they replace. On the OPs boat I would be very surprised if the performance will be affected at all.
However I am with those who would urge caution, but mainly for aesthetic and durability reasons.

 

[CAPTAIN FANTASTIC]

He doesn't race it and I don't think there are enough of them left to make a class.

I think the consensus is that it can be done, but properly, with epoxy and a great deal of care; otherwise it's an extremely bad idea.

I went and joined Classic Boat (didn't that used to be here?) to ask the same question,, but it had already been asked / answered http://www.classicboat.co.uk/forums/showthread.php?t=119997&highlight=carvel+sheath

As usual, thanks for the kind and helpful advice.

Of course it can be done; I have done it; I covered a whole 24ft wooden boat in two/three layers of woven cloth and West epoxy in 1991 and the boat still sails in Cardiff Bay (I sold it long time ago). It was done properly, took a lot of time and cost a lot of money. Did it worth it? all depends how you value a boat.

 

[KenMcCulloch]

I dispute the idea that adding fibreglass and resin to the outside of the hull will add significant weight, below the waterline the displacement will increase pro rata and the weight increase is only the difference between the specific gravity of the materials used and the water they replace. On the OPs boat I would be very surprised if the performance will be affected at all.
However I am with those who would urge caution, but mainly for aesthetic and durability reasons.

I think that is probably ballox. The weight of the boat will increase by the weight of material added. The mass of water dsplaced will increase by the same amount.

Yes it can be done but it is not a good idea for all the reasons already adduced.

 

[Zen Zero]

I think that is probably ballox. The weight of the boat will increase by the weight of material added. The mass of water dsplaced will increase by the same amount.

Yes it can be done but it is not a good idea for all the reasons already adduced.

But the, now dry and not waterlogged, planking will weigh less.

Anyway, I'm against it and I hope when I show him your comments he will be too. He has not got the time or the patience to do the job properly.

 

[Quandary]

I think that is probably ballox. The weight of the boat will increase by the weight of material added. The mass of water dsplaced will increase by the same amount.

Yes it can be done but it is not a good idea for all the reasons already adduced.

Ballox? if it was, then why did you repeat it, if you make a boat bigger does it sink?

 

[OldBawley]

I sail one off those sheathed wooden boats. Sheeting is a method to keep a good lined boat sailing.
All depends on the quality of the original wood yacht. Ours was inland white oak planking. Build 1946, the yacht had a rough time. Beached and sank two times, then given away to who could lift the boat. A four family ownership was made, one of the owners the man who salvaged and rebuild the yacht at his yard near Gent Belgium. Three moneylenders and a fine craftsman. Unfortunately he knew nothing about sailing yachts. They casted a 3 ton new keel, running all the length of the yacht, double the weight of the old keel, made a new “modern “ rig, half the size of the old rig, build a Griffiths dog house on top of the cabin and finally sheeted the restored hull in fibreglass.
Fibreglass was new then, so they gave the job to a paperhanger. He knew nothing about sheeting fibreglass either, but was used to work with wet sticky sheets of **** above his head. I once spoke to the guy, he told me it had been a three months job. All of that for an 8 meter long hull.
They had a lot of money, so no expenses ware spared. In fact a new hull was build around the old wooden hull. Result, a 27 feet waterline yacht weighing 7 tons. They never bothered to take the old boat out. After all, the quality of the woodwork was fine. Not the fastest sailor any more, so they added a big diesel. More weight.
After all of the owners died away, I bought the boat. The hull was still looking good and I had never seen a sailing yacht before, so had no idea I was buying a relic.
It took me 13 years and a lot of changes to get the boat sailing well again, but after 26 years of ownership and living aboard I think saving the soul of of a good boat even with something unholy as glass fibre ( dried snot ) is a good thing.
When I bought the yacht, expertise ( By me ) showed the two hulls had separated due to frost on the hard and rainwater in the bilges. Wood was ok, best quality oak. I glued the two together again by drilling holes in the glass fibre and pumping polyurethane ( Sikaflex ) into the voids.
No doubt some people will write about burial cloth. I am pretty sure I will be in mine before the boat. Après nous le Déluge.

 

[CAPTAIN FANTASTIC]

I sail one off those sheathed wooden boats. Sheeting is a method to keep a good lined boat sailing.
All depends on the quality of the original wood yacht. Ours was inland white oak planking. Build 1946, the yacht had a rough time. Beached and sank two times, then given away to who could lift the boat. A four family ownership was made, one of the owners the man who salvaged and rebuild the yacht at his yard near Gent Belgium. Three moneylenders and a fine craftsman. Unfortunately he knew nothing about sailing yachts. They casted a 3 ton new keel, running all the length of the yacht, double the weight of the old keel, made a new “modern “ rig, half the size of the old rig, build a Griffiths dog house on top of the cabin and finally sheeted the restored hull in fibreglass.
Fibreglass was new then, so they gave the job to a paperhanger. He knew nothing about sheeting fibreglass either, but was used to work with wet sticky sheets of **** above his head. I once spoke to the guy, he told me it had been a three months job. All of that for an 8 meter long hull.
They had a lot of money, so no expenses ware spared. In fact a new hull was build around the old wooden hull. Result, a 27 feet waterline yacht weighing 7 tons. They never bothered to take the old boat out. After all, the quality of the woodwork was fine. Not the fastest sailor any more, so they added a big diesel. More weight.
After all of the owners died away, I bought the boat. The hull was still looking good and I had never seen a sailing yacht before, so had no idea I was buying a relic.
It took me 13 years and a lot of changes to get the boat sailing well again, but after 26 years of ownership and living aboard I think saving the soul of of a good boat even with something unholy as glass fibre ( dried snot ) is a good thing.
When I bought the yacht, expertise ( By me ) showed the two hulls had separated due to frost on the hard and rainwater in the bilges. Wood was ok, best quality oak. I glued the two together again by drilling holes in the glass fibre and pumping polyurethane ( Sikaflex ) into the voids.
No doubt some people will write about burial cloth. I am pretty sure I will be in mine before the boat. Après nous le Déluge.

Great boat story and a robust solution which is an anathema to the traditionalists but the boat floats and sails; and this is the aim.

 

[Seagreen]

Opinion seems to be, if its done right, its very expensive, and lasts, but if done wrong, it kills the boat. I think I've summed it up correctly. If it were me, I'd go traditional, and recaulk/spline etc. That way, its in keeping. I fancy that a half-hearted sheathing job will just kill the boat quicker.

 

[William_H]

Fibreglass sheathing of a wooden boat.

I agree with the OP that to sheath the boat might reduce its resale value as a classic and just detract from what it is. Fibreglass sheathing of course has been done successfully. They used to promote a material called dynel for sheathing. This is a man made fibre which is much more flexible than fibreglass and so follows the wood contours more closely. Of course it must be used with epoxy.

Ultimately you either end up with a fibreglass boat built on a wooden male mold if the glass is very thick.
Or a wooden boat with what can only be called reinforced paint if sheathing is very thin.
The former will last for ever regardless of condition of the wood but is very expensive. The latter may prove to be bad for the wood and a waste of money.
Most efforts end up more like the latter. So no if I had a wooden or plywood boat I would not sheath it.
However there is a type of construction called cold molded ply where ply is quite thin and sheathing is robust that seems to work very well for a one off design. But no where near as long lasting as solid polyester fibreglass. But no never for a wooden planked boat.
You either threat the boat as a museum piece keep it as original with all the work. Or sell it and buy a f/g boat if you just want a boat with easy maintenance.
good luck olewill

 

[Shoalcove]

The latest issue of Woodenboat Magazine has an article on this very subject. They review a method developed by a builder named Alan Vaitses. His methods involve sheathing with a rather thick buildup of GRP and mechanically fastening the layers of fiberglass to the hull. It was a very interesting article IMHO.

 

[KenMcCulloch]

But the, now dry and not waterlogged, planking will weigh less.

Yes I only thought about that after posting, you are quite right. Maybe that was the point Quandary was making, albeit in a fairly impenetrable fashion ;-)
Cheers

 

[Quandary]

Yes I only thought about that after posting, you are quite right. Maybe that was the point Quandary was making, albeit in a fairly impenetrable fashion ;-)
Cheers

No, it was not what I mean't. I was arguing against a suggestion that adding layers of resin and glass to a hull below the waterline made the boat so much heavier that it would seriously affect performance.
To put it as simply as I can using a crude example-
Lets say you apply 25 kilos of resin on a similar weight of cloth. In air that weighs 50kilos, but because you are applying it to the outside of the immersed part of the hull the weight is only the difference between the specific gravity of the layers and the similar volume of water which it has displaced, perhaps 5 to 10 kilos but this is only a guess because I can not be bothered to work it out. The volume of the hull in the water will be bigger because it has been applied outside it, geddit? As the OP says' it will probably reduce the sp.g. of. the existing hull even more by keeping it drier, to the extent that the boat might even float higher. The weight difference will probably be less than the crews lunch so not worth worrying over.
So the influence on performance is not a significant factor in the debate.

It is the same reason that concrete mooring sinkers which seem massively heavy ashore are so easy to move about when kept immersed.