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Permalink Reply by Randy Dersham on October 26, 2008 at 8:22pm

This is the most common repair that Sandy does in our shop.. Most people can do the job themselves if they want to give it a try.

First test all of the blackened wood to see how firm it is. It's easy, poke it with a small screwdriver or awl to see if the wood is soft or solid. If the wood is discolored but still hard then you should allow the wood to dry, pour a thin epoxy like System Three Rot Fix into the holes. This epoxy is thin enough that it will be drawn into the surrounding wood and firm everything up when it drys.

Next use a thickened epoxy to fill the holes flush. We sometimes use West Systems epoxy with wood four added or at times we use a ready made product from System Three called ezFillet. Don't skip step one with the thin epoxy. Using the thickened epoxy only will not soak into the surrounding punky wood and will look good for a short time but not have the long term strength.

If the holes are larger than a 1/4 inch and have a lot of local rot then you should drill them out with a drill. Purchase a wooden dowel to use as filler, then drill a hole to match your dowel into good wood cutting away the rot. Cut short pieces off of the dowel and epoxy them into your new holes. This makes a great patch that will allow a screw for your bottom if you are going to replace the UHWM plastic. A 1/2 dowel will usually do it. This sounds like a big job but is actually takes about the same amount of time as the rot fix and fillet. Sand the tops of the dowels even with the rest of the bottom.

It is not likely that the rot will go all the way through the bottom. I recommend that you use a mortising bit and drill only until you hit solid wood. Then plug. If the drill has to go all the way through then simply glue the dowel into the hole and sand flush on both sides.

To finish your project remember to rough the entire bottom before you apply more epoxy. You will get the best bond if it is properly prepped. Clean it well and rough it up with 80 grit sandpaper.

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Permalink Reply by sanderson on October 26, 2008 at 8:49pm

I think that your first thought is right. I have done many 10 to 15 year old boat bottoms this year. the only problem that I have had is not removing the chine cap, some times you can get leaking through the side of the boat. so i recommend that you remove and replace the chine cap if you are going to fix the bottom of the boat.
After you have the plastic off of the bottom, let it dry for at least a week. this lets you know the deference between rotten wood and wet wood and keeps you from removing more than you have to. then if you have rotten wood you should pick it out and fill it with a thick wood flower mix, or a thickened risen. I have been sanding and rounding the hard chine edge and raping it with 10oz 4 inch fiberglass tape to help the boat keep from leaking. then I put the chine cap with 3m 5200. if you do this with the glass tape you will notice a gap between the chine cap and the bottom of the boat because of the rounded chine. i fill the gap with a wood flour mix to add strength to the hard edge on the bottom of the boat, and to fill the gap. when you put your uhmw back on make sure to use stainless screws, I like to bed them with 3m 5200 to reduce water penetration.

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Permalink Reply by Ken Helfrich on November 4, 2008 at 11:46pm

Remember to put the plastic shoe back on at a temp of 75 UHMW will grow and shrink with hot and cold. 75 is a good mid range temp. Puts less stress on the screws.

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