The Rot Doctor


Subject: Idea on how to fix hole in boat?
Date: Tue, 29 Aug 2000

I have a 32 ft fiberglass sport cruiser boat that hit a rock and punched a 1 inch by 3 inch hole in the keel. Unfortunately this was only discovered after it sat in the water for the summer - long enough to soak up into the wood core of the fiberglass!

From looking over your web pages, I am thinking of drilling holes in the hull above the saturated area and injecting CPES to displace the water and saturate the wet wood down to where the hole is. It hasn't rotted yet - it is just wet.

You shouldn't use CPES to displace water. CPES has some chemistry that will displace light moisture, but not water. Drilling the holes is a good idea, and flushing through with acetone is a good idea. You can also pump air (or vacuum) air through to speed the drying.

If you go through this process, I would also suggest that a few days after the application of the CPES, you also go back and using a turkey baster flow in some of our Layup & Laminating Resin. This is a VERY slow-setting resin that will settle into the wood and add considerable strength and protection against deterioration.

Then fill the hole with Fill-it epoxy filler, then patch the surface with Layup and Laminating epoxy resin & glass (I'll have to work upside down for that)

Right, that's what you do.

Is this the correct way to use your products?


Can you estimate how many cubic inches of wood core can be saturated with one gallon of your CPES?

Can't really say. Everything depends on the absorbency of the wood. On non-deteriorated wood, a 2-quart unit will go quite a long way. For what you describe, I'd say it would be sufficient. For the L&L Resin, maybe a 12 oz unit would do. Again, hard to say.

Have you ever heard of using acetone first to displace the water and dry the wood?

Sure. See above.


Bob D.


You've got the right ideas here. Just be specific, as I've noted above. And come on back if you have further questions.