The Rot Doctor


Subject: Product Recommendations? (wooden fishing boat)
Date: Sun, 25 Apr 1999

Dear Doctor,

I have a 13'-6" Thomson? cedar strip with oak ribs, mahogany transom, open type fishing boat. It has fiberglas on the entire outside surface and heavy varnish over most of the interior. I rescued this boat from a guy who had been keeping it in his backyard for many years. Forturnately, he kept it off the ground with the bottom side exposed to the elements.

Over the winter I have begun restoring this boat. Most of it is in surprisingly good condition, considering the poor storage it has received. I've replaced the top edge rails and a small deck and a small part of the keel. I'm now removing the varnish from the interior, and find the cedar and oak in good condition. The transom and interface of cedar strips is also good, so there is no rot. And I want to keep it that way.

When all the old finish has been removed from the interior, I want to seal all the little cracks, pores, etc. so that water has no place to become trapped. So, I'm looking for your recommendation for a sealing product and also some finish material that is durable.

Right. You are doing exactly the right thing here. After the interior finish is removed, coat with CPES, paying particular attention to the seams, joints and cracks, allowing them to absorb all the CPES they will. This will give you good protection far down the road. CPES alone may be sufficient protection, unless the interior will be subject the extended UV light or you want the final gloss look of a clear coating. In this case, we suggest any marine-grade polyurethane finish. We say polyurethane because we believe it gets a superior grip on the CPES-treated wood. Any varnish with UV protectants will do just fine, however. Paint works just fine as well.

I have also removed the fiberglas from the keel because some of it was loose. There are also a few spots with some fiberglas damage that need repair. Most of the fiberglas is in good shape, so I plan to leave it in place. What product is recommended for the keel and method of blending that area to the existing fiberglas, and what can I use to repair the damaged areas on the hull?

If by damaged areas to the hull you mean the wood, then again saturation with the CPES is the first and best step. If there are voids or cracks to be filled, then our Epoxy Filler will bond with the CPES-treated wood just fine and produce a repair that will last as long as the rest of the boat. Be aware though that the Epoxy Filler dries off-white. If you want a more natural look, then you can mix some appropriately colored sawdust with our Layup & Laminating Resin and make your own paste. This works well, but is hard to sand after it cures -- very hard!

For the fiberglass repair, you will need to use epoxy resin and a light (10 oz or less) glass cloth. Polyester resin just doesn't adhere well to epoxy, and the CPES treated wood will of course be epoxy coated. Beyond this, just proceed as you normall would on a glass repair. We will be prejudiced and recommend our own Layup & Lamiating Resin, because of its simplicity, lack of blushing and better cured flexibility compared to a standard petro-derived resin.

Please note that I'm a fairly good craftsman and have a full set of tools to use.

Thanks very much, Dan M.


Sounds like you rescued this boat just in time. Good for you! If I haven't answered your questions completely or you have additional questions, come on back. We want to be as helpful as we can.