The Rot Doctor


Subject: Feasability of epoxy over wood planks??
Date: Tue, 10 Oct 2000

Having owned a 45ft Matthews (mahogany planked) I'm considering buying a 53ft Matthews (same type of hull), however the bottom was recently epoxied up to the water line. I have serious reservations about this since I've heard pros and cons as to this procedure . I would like your professional opinion if I could beg a few minutes of your time. I ran across your site on the internet while trying to find info on this subject which so far has been very limited. Since wood planked hulls "breath", expand and contract and must be maintained by refastening etc.,seems to me that the epoxy would add stress to the frames and planks and would cause fractures in the coating. I'm not up on the latest in epoxy, resins, and fiberglass techniques so I'm asking your professional opinion If I might. I would appreciate any help you may give me!! Thanks, William B.

Happy to reply.

Your concerns are genuine, but there are some things going in your favor here. Number one, the epoxy is only up to the waterline, so that portion of the hull stays wet and more or less dimensionally stable on Northwest waters. Number two, because you're in the Northwest, it means that the boat is never hauled for prolonged periods of time, where the planks dry and seams open and all hell can break loose in a planked hull that has been epoxy coated. Number three, I will presume the inside of the hull below the waterline is still uncoated wood, so this allows the passage of air and moisture in and out of the wood.

It's not a process I am much in favor of, but it is one that can work here in the Northwest where the boats stay in the water and the water is always makes it hard for wood deterioration to get started below the waterline. I guess if I were you and I was really interested in the boat I would survey the below waterline interior hull carefully and see if you can see the softness or extreme discoloration that indicates wood problems. I would also tap the hull exterior below the waterline, listening for the hollow sound that indicates soft wood. Pay particular attention to the lower areas, where the garboard plank joins the keel timber, back at the engine strut areas, the transom/planks joint areas, and the like. If I didn't find anything serious then I would be inclined to go ahead with the boat -- price and all the rest being satisfactory -- but keeping in mind that you'll have to keep your eye on the bottom for signs of trouble.

Getting epoxy off the wood is a hassle, as I'm sure you know. Not too bad in discreet areas, but to replace a plank it can be a chore.

Come on back if you have additional questions. We're happy to reply.