The Rot Doctor


Subject: Patching the floor in my fishing boat.
Date: Fri, 10 Mar 2000


I need your help...Big Time!

My 12 year old and I decided to buy a 78' Crestliner tri-hull and make it into a nice fishing boat. The floor was spongy in the rear and I decided that I 'd do a simple repair and be done with it. No such luck...the 1/2 ply floor was not only rotted but soaked with gas, oil or both. I could put my hand through the rotten floor and pull out handfuls of material. Next I got out the old worm drive circular saw and carefully set the blade depth to the thickness of the plywood and begin to cut out the bad section. My hole ended up being about 15"X30" and I now have good wood all around to bond to.

Problem is I know how to fabricate a new piece to fit the hole but I have no access to the underside to hold it in place while the epoxied seams are setting. It has only about 1/4' clearance from the glass hull and I'm fairly sure you don't want to bond the floor directly to the hull or I'd just glue a 1/4" strip of treated ply to the patch and the hull.

My question is....after properly treating and preparing the old floor and the new patch will epoxy applied to the seams be enough to hold the patch firmly enough to walk on? If so can you supply me with the right epoxies to complete this job?

I have scoured the internet looking for help on how to complete this repair. You are a true mechanic and a rare breed.

Thanks for any help you can offer,

Rick W.


The epoxy glue would be strong enough, but the question would be the ply edges.

Remember that even though you've cut away the rotted section the rot fungi and their reproductive spores are still likely to be in the remaining wood edges. To stop them from further activity all the edges of the old wood and all of the new wood going in should be treated with a coating of CPES (Clear Penetrating Epoxy Sealer). It won't take much -- a 2 pint unit should do just fine.

I suggest making the repair this way. Cut yourself some strips of at least 1/2" ply or other wood about 3-4" wide and using our All Wood Glue to bond them to the underside of the existing deck to act as *shelves* for the new wood piece to sit on. Apply the AWG to both surfaces and then clamp the strips in place for 24 hours. Now, put your new floor piece in place resting on the shelf edges, again coating all surfaces with the AWG for a secure bond. Allow about 48 hours now for the AWG to fully cure and you're ready to go.

For the wood on the hull edge side if there is not enough room for the shelf, then go ahead and shelf 3 sides and use just the AWG on the edges for the narrow side. Should be plenty strong.

To complete this I'd estimate you'll need a 2-pint unit of the CPES and a 2-pint unit of the All Wood Glue.

If you are going to lay down carpet over the decking, I would suggest that you coat all the decking ply, old and new, with CPES first. This will give you significant protection against future wood deterioration problems. To do this you would need the 2-quart unit of CPES instead of the 2-pint.

Got further questions? Come on back and we'll do our best to answer them.