Rot Doctor


Subject: Leaks
Date: Mon, 19 Jun 2000

Hello Dr. Rot,
I used your CPES to make some repairs to a 1959 Dickerson 32 I have been restoring for the last two years. As far as I can tell, your product made a world of difference. I launched her this May and have received a lot of compliments on her appearance. However, good looks can hide a variety of sins and my boat’s problem is leaks.

She was out of the water for nearly 7 years before she was relaunched and obviously the planks were really dried out. They seem to have swelled up fairly nicely, but some persistent and busy leaks continue. I was hoping, with your experience with wooden boats, that you may know of a method of stopping these leaks. I am reluctant to pull her out of the water - it’s expensive and stresses the hull - and I can’t do it for every leak when one appears.

Any suggestions?

Dale P.


Ah, yes. I’ve been just where you are and it can drive you crazy.

What happens here is that the prolonged drying breaks the seal between the plank and the caulking, so even when the planks eventually swell good sealing does not always occur. All it takes is an edge of paint or a fleck of debris to hold that little portion of the plank/caulked area open and the water will flow in. One tries to get the sealing right before to boat goes back in the water, but it’s nearly impossible without completely re-caulking the hull — a major project as you well know.

Using whatever method you think is appropriate, search-down and mark those areas where the water seems to be coming in. This means head-down in the bilges with a bucket and sponge, but it’ll pay off later. The next time you haul the boat for bottom maintenance, go to that area and remove the caulking and shave the planks clean to the bare wood. Then re-caulk those particular areas. A tip: For a really superior bond, dry the wood surface with a hair-dryer, apply a CPES prime coat to the edges, and after about 20 minutes (in warm weather) go back with one of the caulking compounds (3-M 4200, 5200, 101, or one of the polysulfides) and caulk the seam. If you use 5200 the bond will be almost unbreakable, so if you ever think you will want to remove the caulking we’d suggest the 4200 or the 101.

Meanwhile, do this: Get some sawdust, a pole and a plastic or metal container. Fasten the container to the end of the pole, fill it with sawdust, quickly invert to keep most of the water out, push down to the keel area, invert the can and allow the sawdust to float up along the hull. Do this both sides wherever there is leaking. You can easily deduce what happens: sawdust gets pulled into the leaking seam, it swells, fills the seam, leaking stops. You may have to do this several times. You may also have to mentally gird yourself for the laughs, jeers and questions from the dock.

And thanks for your good word about the CPES. It is a useful product.