Waterproofing an old wooden sailboat with epoxy or fibreglass

[Terra Nova]

Originally Posted by Steady Hand

...All I recall about the hull was that it had been professionally sheathed in fiberglass by a yard in the mid 1970s...

Originally Posted by Steady Hand

...There were no reported problems...

Yeah, right.

[topmast]

I've seen 45 footers sheathed with Battle ship linoleum (last a while dockside) and more ambitious projects with ferro cement hull up to water line. And cold molding with 3 layer plywood. Make a boat outside the boat and hope the interior doesn't rot too quick. Look to house foundation membrane technology for some new tech ideas but old fashioned roofing gum and putty knife can fill seams until she swells each year for smaller hulls.

[NevisDog]

Originally Posted by Steady Hand

All I recall about the hull was that it had been professionally sheathed in fiberglass by a yard in the mid 1970s... Very classy looking boat (full keel).

Thanks Steady,
In the early days of fibreglass (1970s I guess) I can recall folks thought it a great idea to sheath a wooden hull. That was long before the newfangled stuff was fully understood and every sheathed timber-planked hull I can recall from those early days went to an early grave - internal rot induced by sheathing just killed them. Not saying it couldn't be done in those early days but I'd be very, very suspicious.

[Steadman Uhlich]

Originally Posted by NevisDog

Thanks Steady,
In the early days of fibreglass (1970s I guess) I can recall folks thought it a great idea to sheath a wooden hull. That was long before the newfangled stuff was fully understood and every sheathed timber-planked hull I can recall from those early days went to an early grave - internal rot induced by sheathing just killed them. Not saying it couldn't be done in those early days but I'd be very, very suspicious.

I understand.

The boat I saw (online) looked well loved and well maintained. From what I saw, I would have been proud to own her.

[Scout 30]

Originally Posted by buzzstar

Originally Posted by Scout 30 View Post
I think that we should have a rule that when you talk about your boat you have to include a picture. Mainly because I like looking at pictures of boats.


More bureaucracy, even if the original poster of the thought had a good reason and was tongue in cheek. At least one responder liked the idea.

I think you should change your handle from Buzzstar to Buzzkill.

[Scout 30]

You might want to post your questions on the WoodenBoat Forum.

[Wotname]

Originally Posted by Lepke

A lot of old wood boats have fiberglass over the original planking. Professionally done, it can last as long as the wood stays dry. Wet bilges, deck leaks, hose leaks will kill it. Also the hull is much heavier than it's original design.

Yes, agree but I'm not sure if much heavier is correct and maybe slightly heavier would be an understatement. So that leaves just "heavier" .

To be even partly successful, the hull must be dry and remain dry; this means the wood part of the hull is now lighter than it's design weight as it's design weight includes the moisture taken up by the timber below the waterline. I understand this to be about 20% of the hull weight (below the waterline).

[Wotname]

FWIW, I once saw a rather shippy little 25' carvel hull on the hard that had been riddled with worm. It was just a mass of tunnels below the waterline. It had been on the hard for 5 years or more with all the paint stripped off (inside and out).

It was then painstakingly fitted (injected) with epoxy and then sheathed over externally and coated with epoxy internally.

Can't say how well it lasted but I suspect it would have lasted decades not years. Clearly it was a right off otherwise.

It must have a labour of love rather than one of economics.

[IdoraKeeper]

Do all the work you need until the condition of the boat meets your specs. When you put her in the water let her leak a bit and then hire a diver to go over the leaks with saw dust..presto the leaks will decrease and then stop. Much cheaper than alternatives.

[Araq44]

Originally Posted by earthmover

I would like to re-furbish an old wooden boat. I don't want the hassle of pre-soaking in water each season so the planks expand to seal it. I want to coat it in resin of some type. Is this possible? Tried to add picture of boat but didn't succeed.

I restored wooden boats for a living for 5 years and have been doing it as a hobby for 20+ years (power and sail). What I have seen is don't do it unless you live somewhere with little to no humidity. Wood and epoxy expand and contract at different rates, no matter what. This causes rot.

Polyester is a filler, not a bonding agent. Do not use Polyester as a bonding agent.

If you look at wooden ski boats that were fiberglass over wood they all rot inside of 10 years unless they are in Nevada, Cali, Canada, etc. look for one in Florida and you won't find one because it has dry rotted out.

[double u]

...the krauts used to call this epoxi/glass-cover of a traditionally-built wooden boat a "shroud" as in "the-cloth-used-to-cover-a-corpse" ("Leichentuch")

[valhalla360]

I believe the main issue is:
- A true wooden boat: the wood can breath, so the planks can swell when moist and shrink when dry. They can move relative to adjacent planks and because they have access to oxygen, they have less tendency to rot.
- A true cold molded boat: The wood is completely sealed inside and out, so it doesn't swell and the wood stays dry. As long as the sheathing isn't breached, the wood won't rot and the boat can last for decades.

Slapping a coat of epoxy on the exterior of a wood boat doesn't work so well. The interior still has access to moisture laden air and water in the bilge. As the wood expands and contracts due to moisture variation, it eventually breaks the bond with the exterior epoxy. Now you have an area that moisture can get into without access to oxygen, so rot can accelerate. Worse, the rot can be hidden under the layer of apparently solid fiberglass, so it can proceed without repair for longer.

If you want to disassemble the boat and seal it inside and out, that can work but it's a major project (not really worth it in most cases) and miss a spot and it can still fail.

[Wotname]

^^ V360 has nailed it - IMO.

[Cadence]

Originally Posted by Wotname

^^ V360 has nailed it - IMO.

One more in agreement!

[knockabout]

180 marine epoxy /