Old wooden boat

[Duco84]

Please advise experiences and opinions for covering of old traditional wooden boat with fiberglass and west epoxy but only from outside! Wood is in good condition.

 

[bajansailor]

Coincidentally I just posted some comments about Curlew (a 100+ year old yacht which was epoxied on the outside) on another thread - have a look here :

Risk of wood rot on a well maintained boat? https://www.boatdesign.net/threads/risk-of-wood-rot-on-a-well-maintained-boat.64541/#post-889008

 

[Rumars]

Wood is in good condition.

If that is true why apply fiberglass?
It can be successfully done, but it's not as simple as it sounds.

 

[fallguy]

Scale is a big issue here. It would be best to discuss the hull in mind.

 

[Duco84]

If that is true why apply fiberglass?
It can be successfully done, but it's not as simple as it sounds.

Problem is time for maintenance. Every year I should paint... I have experience with epoxy and oak but wood is isolate from each side with epoxy. It is very good solution, only problem is sun and varnish, but for hull and white 2k I don’t expect problems. I have experiences with Poliester and glass over traditional wooden boat, but that is not good solution, due the adhesion between wood and Poliester. Epoxy would glue, but I worry about the humidity and dilatation of wood...

 

[Rumars]

If you need to paint every year the structure has problems or your paint is really bad. Only traditional varnish would need yearly renewal. What kind of boat are we talking about? Open boat, decked? What's inside varnish or paint?

 

[Duco84]

I’m using Hempel white paint for hull outside. It is decked, inside no need for painting. All traditional made boats, regardless the paint we paint once per year.

 

[Rumars]

Duco, tradition is not a reason. I suppose you are not waisting money and time every year repainting good paint, so the planking must move enough to crack the paint at the seams.
If you want the sheating to be successful you need to know why things are like they are. For example not painting the inside allows more moisture into the wood and more movement. Storing the boat on the hard in the wind for 6 months let's the hull dry out. Planking made of oak will move more then one from pine. Plain sawn wood moves more then quartersawn wood does. Plank width and thickness is also a variable, as are the fasteners and the art of the framing.
So again, why are you painting every year? How is the boat fastened, what is it made of, how is it operated? A good sheating job adresses all of this variables.
For example some boats are best done by sawing the existing planking in the middle and splining the cut, others don't need this.

 

[Blueknarr]

Unless it is antifouling, the paint should last much longer. Almost a decade longer.


As Rumers asked

Why is it failing that quickly?

 

[Duco84]

Planking are made from pine and frames are from oak. Boat is painted from inside. During the winter time it is high humidity and there is a lot of rain, while during the summer temperatures are more than 38 degrees. This cause cracks of paint between the planks. In this area (Adriatic sea), all wooden boat should be painted once per year.

 

[brendan gardam]

You can spline and epoxy a carvel timber hull, then remove the ribs and epoxy glass the inside; you end up with a fully encapsulated hull but what a huge job.

 

[Rumars]

You need to spline the hull and not only the existing seams but split the planking such that no plank is more then 50mm wide. This will convert the carvel to strip plank and stabilize the hull. My preference is to also glue the ends into the rabets but it is up to you. All mechanical fasteners must be tight. Follow with a 400gr/sqm biaxial cloth in epoxy. Inside I would paint with an epoxy paint. For all this the wood must be dried to 12%, especially the centerline timbers. If the deck is also carvel it must get the same treatment. All edges rounded over so that the fiberglass does not crease.

 

[Duco84]

You need to spline the hull and not only the existing seams but split the planking such that no plank is more then 50mm wide. This will convert the carvel to strip plank and stabilize the hull. My preference is to also glue the ends into the rabets but it is up to you. All mechanical fasteners must be tight. Follow with a 400gr/sqm biaxial cloth in epoxy. Inside I would paint with an epoxy paint. For all this the wood must be dried to 12%, especially the centerline timbers. If the deck is also carvel it must get the same treatment. All edges rounded over so that the fiberglass does not crease.

Thank You, please explain "glue the ends into the rabets".

 

[Rumars]

The rabbet is the angled pocket on the stem and keel where the plank end sits. The garboard (first plank from the keel) also sits in such a pocket. If the planks are screwed you can take the screws out, clean the surface and put thickened epoxy in there, glueing the plank ends to the stem and the garboard to the keel. If the planks are nailed or you don't want to do this, you do the same as with the plank seams, cut a groove and fill it with thickened epoxy and a wood batten (spline). If the corner between plank and stem/keel is concave it must get a fillet of thickened epoxy so that the fiberglass lays smooth, but that depends on how exactly your boat is buildt.

 

[Rumars]

A video showing the splining.