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Permalink Reply by Rick Newman on September 27, 2011 at 7:47am

Chuck, the question that comes to my mind is why is this the only section with rot? What inspection steps did you undertake? The ever popular poking with a sharp screwdriver in potential areas or the more rare ice pick method are two that I would suggest. In the picture you have included the upright frame member looks suspicious.

Here is an excerpt from Wikipedia that shines some light on the characters that cause the problem:The term dry rot is somewhat misleading, as both species of fungi Serpula lacrymans and Meruliporia incrassata do require an elevated moisture content to initiate an attack on timber (28–30%). Once established, the fungi can remain active in timber with a moisture content of more than 20%. At relative humidities below 86 percent, growth of serpula lacrymans is inhibited, but it can stay dormant at relative humidities down to 76 percent.^[1] These relative humidities correspond to equilibrium moisture contents of wood of 19 and 15 percent, respectively.

Yes I know its long but it suggests that a moist environment can start and continue the problem. My concern for your boat is that the rot is more widely spread than is obvious from the surface. I am willing to bet a six pack of adult beverage that there is more rot. In my limited experience and in recounting the previous examples of other boats exhibiting similar problems the oft suggested remove the outside chine and perhaps the bottom reveals the hidden damage and leads to a successful, long term repair. AJ and his crew from Wyoming have resurrected numerous boats with similar conditions.

 

Was there ever a UHMW (plastic) sheet fastened to the bottom? Have you ever turned the boat upside down to check its' condition?

 

The bottom line (pun intended) is that the time and money spent now might be less than if you do a patch/bandaid repair now rather than a more complete repair that will allow the boat to be handed down when you are eighty!

 

Good luck, yes some more pictures would be handy. Take a look at my page and pictures of the boat I disassembled and the conditions I found.

 

Rick Newman

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Permalink Reply by Chuck Strum on September 29, 2011 at 6:39pm

Rick,

Thanks for the detailed reply.  To respond to your questions...

I suspect that is the only section of rot because for the two years I have had the boat (only one stored outside) that side was the low "downhill" side...where water would puddle if it got under the cover.  Here in Montana, snow sits on the cover for long periods, if it leaks slowly, the water would run to the side where the "rot" is apparent.

 

Yes, there has been a UHMW skin on the bottom since day one...over 20-years.  When I got the boat from my dad two years ago, my first winter project was to refinish the outside and bottom, including removing and re-installing the UHMW skin.  I sanded the bottom completely, filled screw holes (from UHMW attachments) with epoxy, and finished with 4-5 coats of a marine finish I got from WestMarine (don't remember the exact name).  I did not notice any bottom rot at that time.  I know I've got to turn it over again, pull the UHMW, and have a look.  I just haven't done that yet.

 

I knew when I did the outside/bottom that the inside needed attention, but did not know it was as bad as I found this year.  My dad admitted injecting some epoxy into the ribs (upright frame members) and the inner chine some years ago...indicating a problem that pre-dates the two years I've had the boat.  As he said...."the old girl needs some attention".

 

I will turn it over, remove the UHMW skin (need to anyway to remove the ribs), and the outside chine, to see what's underneath, and will post pics.  I'm just dreading complete removal of the bottom, but if its necessary, then I'll just have to do it.

 

As a post-script, have you had problems with the UHMW bottoms working loose from the wooden bottom?  I find that the screws continually work loose.  I'm thinking its due to differing coefficients of expansion of the two materials.  Any insights?

Thanks again for your input...I'll keep the thread going as I explore more.

Chuck Strum

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Permalink Reply by Rick Newman on September 29, 2011 at 7:06pm

Chuck, I haven't had any issues with UHMW bottoms cause I sold mine before ever installing it.

However others that live in similar climates to you and me, I live in Spokane, have had similar issues with the UHMW pulling screws and introducing water and such into the bottom. In Southwestern Oregon where the use of the UHMW bottoms started the range of temperatures is not as great hence the success they had with them. A wonderful alternative to the UHMW is a 1/4" plywood shoe. Do a search on Dave Z and you will find a wealth of information on their preperation, installation as well as andecotal experiences that he and others have had.

 

Good old physics, once again explains the mysteries of our wonderful craft, wooden drift boats! Moderate temps, moderate stretch, extremes of temp, extremes of stretch.

 

Please keep us informed. We love pictures too.

 

Rick Newman

 

 

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Permalink Reply by Chuck Strum on September 29, 2011 at 7:57pm

Rick,

yes, I lost the bow section of UHMW this last summer...decided to replace it with a section of 3/16 plywood.....as a sacrificial surface.  Holding good so far.  I finished it top and bottom with good marine finish, then screwed it in place.  Planning on replacing when it gets scared up!  Will probably be easier to replace than the UHMW, but won't slide over the rocks as easily!

 

 

 

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