The Rot Doctor


Subject: epoxy bottom
Date: Mon, 30 Oct 2000

Dear Doc,
I purchased a 1965 60' custom built boat in 1998. It is 1 1/8 mahogany plank on mahogany frames. The bottom (from waterline down), is covered with multiple layers of epoxy and cloth about 3/8 inch thick. I have pictures of the job being done in Florida in 1988.
I had it out of the water in Port Townsend last year and replace several planks. One plank was half way covered with the epoxy cap. The only rot was above the cap. The wood underneath the epoxy cap looked brand new. Also, when trying to remove the portion of the epoxy on the plank I had to cut a border with a grinder and then apply heat with a torch to remove the piece. Prior to the grinder/torch method, I tried using chisels and large grinders, they all failed to remove the cap. It seems that most shipwrights that I talk to claim the epoxy cap will delaminate over time. I am concerned for safety reasons but also for resale problems.
I would appreciate your opinion and any experience you may have had with this type of situation.
I am located in Raymond, Wash. When I finish the restoration, possible plans for the boat are to take it to mexico. Do you think the warmer climate would be a problem for the boat?

tom s.

P.S. Great web site.

When the shipwrights say "delaminate over time" I would guess they really mean "separate from the wood hull over time". The epoxy sheathing itself should not delaminate in your lifetime.

Since this work was done in 1988 and, as you indicate, the wood looks fine under the laminate, then I wouldn't worry about it at all. ANYTHING can happen over enough time, but if there were any built-in problems they would have showed up on your hull by now. The secret to successful epoxy sheathing is having absolutely dry wood. Sounds like whoever did it in Florida did a good job. Be very careful when replacing removed epoxy sheathing to have dry wood and a premium epoxy to re-make the enclosure.

Since this boat has been in southern waters and is showing no signs of significant deterioration, then I wouldn't worry about it too much in Mexico. Mexico is generally fairly dry. Believe me, if a boat can survive in Florida it can survive anywhere. I've had boats in Florida and it's a brutal climate for wood boats.

Because Mexico is warmer, you can expect an increased vulnerability to above water-line dry rot. Just keep your eye out for it, and get on any soft wood as soon as possible. I highly recommend that you keep CPES (Clear Penetrating Epoxy Sealer) on board, and whenever you notice suspect wood you get after it with the CPES. If CPES had been available when I had boats in Florida and the Carib and the South Pacific I would have saved myself a lot of grief. I would also suggest that if you ever wood the topsides, before applying a new final coat you seal things off with a coat of CPES. Pay special attention to the sheathing/wood boundary, because that's where the deterioration will get started -- as you have already discovered.

Stay in touch with us, and if you have access to a digital camera you can send us pictures using the jpg format. We're always happy to look at these and offer any suggestions that come to mind.