Finding rot advice needed

[film842]

I need to take a close look at a 30 year old wooden boat this weekend and the only thing I know about finding dry rot is the ice pick method.
This boat is constructed of mahogany marine ply longitudinal planking over clear fir stringers. It's a simple but somewhat unusual design and it has not been covered in epoxy.
Besides banging away at different sections and using the ice pick for soft spots, can anyone give me any other guidance on how to find rot?
Thanks,

[hansp77]

just general advice, but,
Use your nose- literally.
Unless it is all out of the water and completely dried out, the 'dry rot' will most likely be damp, and should have a notable smell.
Other than that just look absolutely everywhere- take your time.
Good luck.

[Jay Greer]

Tapping with a hammer and poking with a pick are accepted methods of finding soft spots in boat hulls. However it is an art rather than a science. If there are any areas of endgrain showing that are not sealed, this is a common spot for rot to get started. Look of expansion of the grain in these areas. Any break down of fibers should be suspect. Pressing on these areas with the fingers and finger nails can yeald a feeling of softness under the first ply that could be a problem. Also, look for checking along the grain and bubbles in the surfaces.
Jay

[Andrew Craig-Bennett]

Thirty year old mahogany marine ply may be better stuff than you would get today!

Hans and Jay have given excellent advice.

Look very carefully at the paint - any signs of crazing are very bad.

Remember to stand back and sight carefully along to see if everything is lying fair - chances are, with a ply boat, it will be - if it isn't, things are badly amiss.

Tapping methodically with a light hammer is as good as any other method.

[film842]

Thanks for the advice and tips. I'll use them all and will especially try and take my time about the whole process.

I'm also counting on the fact that 30 year old mahogany plywood is superior to what is available today. Although the original shop that built these boats is now closed due to the owner's passing, I do know that they were reputed to have used the best materials available.

[Bob Smalser]

Do you have a moisture meter? Rotten wood is always considerably wetter than the sound wood surrounding it. Knowing where to look is the biggie, but a moisture meter can confirm what the ice pick and hammer tell you.

And double check any "epoxy" fillets....there are quick-fix goos that set up too hard to get an ice pick through that may be hiding major rot beneath them.


Brown Rot, White Rot and other Wood Pestilence (http://www.woodenboatvb.com/vbulletin/upload/showthread.php?t=71429)

[seo]

Good advice above. If the wood is absorbing moisture, the paint is unlikely to be adhering well. So, lifted paint+moisture=good spot for rot.
Look for places where water pools on the inside of the hull, undrained frame bays, clogged limber holes, etc. Boats generally rot from the inside out.
Look for end-grain that's been soaking up water.
Use a plastic hammer, not metal.
I use a thin-bladed "exacto" kind of knife, not an ice pick. The knife can go in with the grain and leave barely a mark, while round ice picks leave a telltale mark.