Restoration - epoxying the bilges...

[Andrew S/Y Rocquette]

OK. Search facility still Pete Tong (1), so apologies for any replications of this topic.

Situation is thus: Rocquette is a 42 foot double-carvel glued hull (effectively cold-moulded), who additionally is having 2 veneers added to the outside of her hull during restoration. Interior/bilges has seen new ribs, and replacement bottom half-dozen planks from the garboards.

Question is: Do we attempt to coat the interior with low-viscosity epoxy to seal the bilges?

Or is this doomed to failure as there's practically no way of getting a universal coverage in this situation, and we're only going to trap ingressing water under an epoxy coat that is not perfect in its coverage? Are we better utilising a breathable paint finish so any moisture which gets into her can escape? Does it in fact matter...?

One thing to say is I do not have access to CPES at a reasonable price, so please do not suggest that as a solution!

Thoughts please...to epoxy or not. That is the question...

Cheers
Andrew Thomas
S/Y ROCQUETTE

(1) UK rhyming slang for "gone wrong"...sort of equivalent to SNAFU... smile.gif

[Dan McCosh]

This is bound to be a controversial subject. Still, I would say no, as the epoxy in the bilge water would simply trap moisture, and it would be unlikely to do more than slow the penetration. I'm of the opinion that cold-molded layers on the outside should have wood that can "breathe" on the inside.

[Bob Smalser]

I don't think you'll get a good answer because there I don't think there is a good answer....only what somebody has practiced and likes over the short term relative to the life of your particularly old hull.

Epoxy "breathes"....but very slowly. Does it breathe enough? In old wood, are you trapping undesirable life forms in there? In old wood that's used to being athletic, yet has become a bit more brittle, are you inhibiting natural seasonal movement to the point of negative effects over the long haul?

Paint is spose to "breathe" more than epoxy. But not all of them....ie, polyester certainly doesn't and there's no doubt in my mind that too much of it contributes to rot.

My Uncle Paul, who built traditional boats from 1920 to 1970, primed the insides with thin red lead followed by a very thin wash coat of white lead paint, because he wanted the moisture in the wood "to have a place to go".

[JimConlin]

I don't think there's a good answer either, but would add to the list of concerns the question of whether the surfaces could be gotten clean enough to hope for a good bond.

[Puka]

Oooooh boy! have I laboured over this one, and are still sitting on the fence. Gonna have to make a decision soon.

[Peter Malcolm Jardine]

My Uncle Paul, who built traditional boats from 1920 to 1970, primed the insides with thin red lead followed by a very thin wash coat of white lead paint, because he wanted the moisture in the wood "to have a place to go". There is no down side to this treatment in my opinion.

[Puka]

I dont have a traditional built boat.(Edge glued,
strip plank.)
And, I am going to sheath the outside in epoxy/ glass.
So that leaves me somewhere in between.

Andrew's, is glued as well,with no glass over?
Probably more suited to free breathing bilges.

[RonW]

This is a hard core and interesting subject. I was hoping to see more posts on it. The problem with wooden boats they rot, and generally from the inside out, where there is trapped moisture and poor air circulation. Even trailer boats with limber holes, impeede the flow of water and hold moisture behind the frames, and worse yet dirt, which sucks moisture from the air and holds damp moist dirt next to the frame which causes rot.

It is a fact that epoxy will allow water to penetrate through it, but even though it slows the penetration, it also slows the evaporation.
What paint once it becomes thick enough to be a film, is actually breathable. Or does it become more of a hinderance in the evaporation process,and the bottom of your boat is a big difference from the vertical side of your house that beside being vertical also receives plenty of air circulation as well as direct sunlight.And the shady damp side of your house is where the paint always peels and blisters, sure signs of moisture entrapment.

Red lead in a thin primer coat, thin enough you can still see the wood grain, would be breathable, and deter mold and fungus that leads to rot.Cuprinol or copper napthanate applied before a primer coat of red lead, should give the maximum protection possible in todays world.

And then what about the little pockets that traps and holds water. I thought there was some excellent posts about filling these with concrete.
Many good testimonials from those familar with it and actually had experience with the process. Those that opposed it, as I remember, was only opposing it on theory. But I (do not) remember reading one post where someone said they filled pockets with concerete over clean good wood, and 20 years later dug it out, and all the wood around the concrete was good, but the wood under it was rotten.

In my humble opinion, a clean, solid and dry bilge, sprayed with cuprinol, allowed to dry for 4 or 5 days, followed by one thin primer coat of red lead, and then pockets filled in with concrete. Couple of bilge fans installed that can be turned on periodically to circulate fresh air.
Or at least that is what I think.

[Spissgatter W-9]

In reading this and other threads, the reoccuring theme suggests that positive experience over a significant period of time is valuable guidance. Accordingly, soaking a wooden bilge periodically with in the ages old mixture of pine tar, lindseed oil and turpine has demonstrable efficacy. Are there compelling reasons to adopt something else?

[Stiletto]

You may not have access to CPES but you may be able to get Everdure which is an Epiglass product with similar properties to CPES and the added bonus of a fungicide/preservative in it.

I wonder how much water ingress there will be after the new skin is added to the exterior, and presumably glassed. My GOP trimaran often has dust in the bilges, any water that does get in tends to be from rain coming in through a leaky hatch which is undergoing repair at the moment. Fresh water is, of course a bigger problem than saltwater so needs to be dealt with.

If, as I am assuming, the new skin is glassed then the basic nature of your hull has changed, (although not much, as the carvel was glued).
It is not strictly speaking a traditionally built hull, so should be considered from that point of view.

If there wasnt much rot up until the repairs were made, why bother.

[ 06-07-2005, 05:38 PM: Message edited by: Stiletto ]

[Andrew S/Y Rocquette]

In answer to some of the above - she was effectively cold-moulded originally although 2x carvel planked. The new layers are not fundamentally altering this structure, and is why we've gone for it - it's in sympathy with her original construction.

She was tight before, and will definitely be afterwards - only water ingress will be stuffing gland, down the mast (fresh water - yeurch!) and anything over the deck that finds its way down anchor downleads and open hatches.

I'm thinking the non-epoxy route is the way at the moment. Camper and Nicholson have put me onto International Paints who are advising on the restoration of Gypsy Moth IV. Will let you know what they say....

EDITED TO ADD: And International suggested either epoxying, or if there were concerns over adhesion over previously painted surfaces, then to use their yacht primer. In either case they then said to use "Danbolin" which is their bilge paint system. It's important to note that both solutions are (largely) impermeable to moisture, so I think conccerns about a full sealing process still stands.

Re the traditional tar/linseed mixture - as ribs are epoxy laminated, there are some concerns about soaking in an oil-based solution...

So that's where we are. Not a lot further on, methinks!

[ 06-08-2005, 06:11 AM: Message edited by: Andrew S/Y Rocquette ]

[wyndham]

How dry is the exposed wood now? Is it all sound and in good shape? If so what prompts you to anything new? Attempting to "Seal" the bilges seems a bad idea in any case, you're never eally going to seal anyhting but will trap moisture that will surely lead to problems down the road. Some thinned red lead primer as suggested earlier, liberally splashed about to keep the mold and fungus at bay, let the wood breathe and offer some minimal protection would be my preference.

[Andrew S/Y Rocquette]

Dry and sound at the moment...

[wyndham]

The wood in the bilges is exposed? No coating at this time? Can you get to all of it? See all of it or are there engine beds, pumps, bulkheads etc. in the way?
Assuming you could actually lay your hands on every single square inch of exposed wood then in theory you could googe the whole shooting match.
Again though I would wonder why? If there is no rot there now and you keep the bilges halfway ventilated and pumped out as necesary what is your concern?
What kind of wood is the inner layer? You say she is essentially cold moulded. Of what? Ply?

[Andrew S/Y Rocquette]

Originally posted by wyndham:
The wood in the bilges is exposed? No coating at this time? Can you get to all of it? Exposed, was painted, new laminated floors replacing the original galvanised,

Originally posted by wyndham:
What kind of wood is the inner layer? You say she is essentially cold moulded. Of what? Ply?The bottom 3-4 planks replaced (with strip-planked replacement), but inner planking was originally spruce (not too durable...). Outer was (is) mahogany.

A

[Cullen T.M. McGough]

Epoxy is for sissies.

Go get the bucket of hot tar.