Wooden boat advice needed

[Sandro]

Good morning,
I address all the forum experienced readers for advice on a matter of important consequence – for us.

My brother Gianni, about 1970 bought Cupido, his first decked boat: a 6 metre mahogany sloop with traditional long keel, built in 1962, a nice boat whose model name was “Vento del Sud”.

A few years later, the family growing, he sold her on Lago Maggiore lake.
After upgrading, upgrading, and then downgrading in boat length in the years – as many do – a few monthes ago he found Cupido for sale always on Lago Maggiore, near where we live.
He sold his Cornish Shrimper and bought back Cupido.

Of course the boat was weathered and aged, the hull had been sheathed outside in GRP, there was some rot, a few cracked ribs, etc.

Gianni is of a courageous kind and started a complete restore.

He had a trailer and a cradle made, suitable for the boat and carried her in a shed we have.
He began by removing the plastic sheath and he did well because it was completely separated form the planking, allowing water in between.
Then he gutted completely the interior for accessing the whole hull.
He hired a free lance carpenter who is now working a good share of his time on this project.
Many timbers were replaced, many ribs were doubled with laminated ones, stainless steel strengthening floors were added, the iron keel was detached and sent to redrill the rusted bolts, the teack deck and beams and the main bulkhead will be renewed. All summed up, a good work, if long, is going on.

Now the question.

The initial plan was to coat again the outside of the hull and keel with thick GRP, acting also as a reinforcement of the whole boat, but making sure that the resin would adhere solidly with the planking.

Now the structure of the hull proved in better condition than expected and strengthening parts have been added.

What is better?
A): Coat the hull outside with GRP
or
B): leave the planking free, just caulked and painted?

Gianni is in a fierce doubt: to coat or not to coat? He asked many professionals who should have experience in the matter: the opinions are mixed and no one took a positive position.
It must also be said that the boat will not be permanently in the water but will spend long spells high and dry in the cradle.

I proposed to hear the advice of many practical persons and here I am writing.

We expect to hear the opinions and the pros and cons of many forumites. This will help to make the right decision ant to avoid a mistake of big consequence.


Gianni and I thank all those who would spend a little time giving their thought.

Sandro

 

[Seajet]

I suspect she'd be better off without any sheathing but people with more wooden boat experience will be along shortly.

 

[Poignard]

B)

 

[DanTribe]

GRP sheathing often causes problems with old boats by allowing rot to develop unseen, especially in fresh water.
There have been many successful restorations using epoxy saturation methods. West systems are well known
http://www.westsystem.com/ss/assets/howto-pub2/Wooden Boat Restoration and Repair.pdf.
Any pictures?

 

[itchenseadog]

A) No, No, No, No........................No. A wooden boat must be allowed to breath and move
B) Yes!
After 45 years building and repairing wooden boats of all types, I have not yet seen a grp sheathed hull that has not either blistered or parted company with its wooden substrate.

 

[Gordonmc]

As a former wooden boat owner (now ferro) I would reinforce the advice already given that sheathing in fibreglass is inherently bad.
Consider that the planks on a carvel hull will move independently of each other, which is why caulking works.
That said, the future for the boat as described, use in fresh water and long periods in a cradle, does not bode well.
If out of the water, even in the wet West of Scotland, my mahogany hulled carvel hulled boat would dry out in a short time. It would take a couple of days for the planks to take up when back in the water.
My advice would be: do not sheath the boat; caulk and paint the hull; after refit leave the boat in the water; put a bucket of rock salt in the bilge-water; regularly treat the inside of the hull with a biocide, such as glycol-based anti-freeze.

 

[Lakesailor]

I would tend to agree. My clinker dinghy had been epoxy saturated below the waterline by a previous owner, but it didn't stop it leaking like a sieve, It was kept out of the water a lot of the time.

It sounds like the boat in question is carvel so maybe there are better caulking materials these days which will accommodate drying-out/taking up.

The West System seems aimed very much at carvel construction.
Interesting document here http://www.gurit.com/files/documents/restoration-guidepdf.pdf

 

[PhillM]

I am NOT an export, but everything I have read about sheathing seems to point towards it as a method of extending the life of a "dead" boat. Sooner or later the water will get in and rot the hull.

I did the research because I was advised by a respected yard to sheath Paean when we first bought her. Instead we had the job done properly by others and I am very glad I took that route.

I know there is a forumite who did this to his boat and its been fine and as with every rule there will be exceptions.

For what its worth, if the boat has been properly restored there should be no need to sheath it and if the job has not been done well - you need to talk to the carpenter!

 

[Tranona]

Definitely do not sheath. You will not get GRP, even using epoxy to stick to a flexible hull. The only possible use of resin is to encapsulate every individual piece of wood in epoxy before assembling to reduce the moisture content and slow the natural expansion and contraction.

The only thing you can do is use a conventional paint system and keep the whole boat covered when not in use. A good paint system and protecting the hull from sun, wind and fresh water (rain) will keep movement to a minimum, but you may just have to accept that seams may not stay watertight without the boat being in the water.

 

[dunmor]

B

 

[oldsaltoz]

My advice:
Don't sheave the hull and don't leave her out of the water.

Good luck and fair winds.

 

[ripvan1]

Is cascover still available, I saw a big old boat that had it and I suppose it stretches with the wood movement and is it not porous so not trapping moisture?

 

[andygc]

I have a wooden boat, a little older than yours, and also carvel planked.

but will spend long spells high and dry in the cradle.

There lies sadness, heartbreak, and a need for a reliable mains-powered pump. The boat will open up, and will sink when relaunched unless continuously pumped for 2 or 3 days. If you are unlucky, and the planking has been laid a mere fraction too tight, the drying out and soaking up will generate enough force to crack frames. My boat had major repairs 10 years before I bought her. She was in the yard for the 3 years immediately before I bought her, having previously been in and out each season, and well used, so no apparent problems. Two seasons later we had to repair 8 frames which had cracked through along the length of the replaced planking. That was despite the boatwright having allowed his usual ha'penny gap between new planks. The planking (oak) actually swelled bigger than it had come from the timber-yard.

The boat now comes out for a few weeks for seasonal maintenance then sits in a mud berth for the winter. There's insignificant drying out, and no leaks at all.

If your boat is going to sit in a cradle you might as well epoxy inside and out and then sheathe her - making her into a WRP (as opposed to GRP) boat. There'll be little movement because the epoxy will slow the rate of soaking up and drying out, but you need to make sure that the epoxy has covered everything.

 

[30boat]

In the old days people used to sheathe old hulls that had reached the end of their lives in ferrocement.I've read several accounts on how the boats became lighter than before as they dried.I wouldn't advise it to the OP though.

 

[Tranona]

Is cascover still available, I saw a big old boat that had it and I suppose it stretches with the wood movement and is it not porous so not trapping moisture?

No longer available - and never an easy process to do. Is not porous. I have a Cascover sheathed boat and have done small repairs with eopxy and glass cloth, but it is ply and therefore stable.

 

[Keith 66]

If he is going to the expense of a major refit or rebuild sheathing in GRP will be the kiss of death & counter productive.
It may extend the life of a worn out boat but conversely will shorten the life of a good one.
Even if using west system the bits of wood are simply too big to seal effectively, the joints will crack & water will get in. Then the rot will start.
I have seen too many good boats ruined by glass sheathing or slathering in epoxy.

 

[Lakesailor]

The problem is that epoxy isn't flexible and will tear the wood before it gives up itself.
Surely there are elastomeric caulking compounds now available which will allow for shrinkage and expansion.

 

[pmagowan]

Under no circumstances should you sheave the outside of a wooden boat in grp. It will simply trap moisture, and worse it will trap fresh water and the wood will rot. If you mix grp and wood then the wood MUST be completely encased without a single screw hole or crack. This way the wood is kept dry and stable. It is almost impossible to do this on an old boat.

 

[andygc]

Under no circumstances should you sheave the outside of a wooden boat in grp. It will simply trap moisture, and worse it will trap fresh water and the wood will rot. If you mix grp and wood then the wood MUST be completely encased without a single screw hole or crack. This way the wood is kept dry and stable. It is almost impossible to do this on an old boat.

Under no circumstances? There was a boat in the Exe which could have been a bonfire, but somebody chose to have it restored. The gaps between the planking would take a finger, so Mike Trout reframed the hull, refastened the planks, splined all the joints, fitted new floors, and then epoxied everywhere, finishing with a thin sheathing (not the heavy sheathing suggested in the first post). Result, a boat that'll go another 25 years and may then be a bonfire, maybe not.

The boat in this thread is going to spend much of its life out of the water. The hull will open and close like a venetian blind, especially where the sun shines on it and when the wind blows. The paint finish will crack along every seam. Wooden boats need to be kept wet, and preferably not with fresh water.

Lakesailor, I don't think there's an elastomeric compound that will work in a gap that goes from a few thou to 3/16 or 1/4 of an inch in 6 months, still adhere, and not exert unacceptable loads on the frames when fully compressed.

 

[PhillM]

Of course its worth considering if the boat HAS to spend a lot of time out of the water.

We were out for 7 months last year and I was getting worried. I hope never to have to be out for that long again. This year she was out for only 7 days.