"Ed Edelenbos" wrote
Hmmm.... I guess it must be different for working people. I've known
several boat yard operators and pile drivers who use this method (for
their own boats). Actually, the most common way is to use regular epoxy
resin and thin it with acetone to the right consistency. I know of a
couple rib repairs that are about 25 years old and still in place.


It depends very much on what the original structure was like (ie massive
workboat construction or slender scantling yacht type); and what stress
it's put under.

From an engineering standpoint, Glenn's comments are 100% accurate.
Epoxy saturation restores much of the strength in compression of the
original wood, some of the shear strangth, and very littl of the
strength in tension (which is wood's strongest point).



Glenn Ashmore wrote:
Epoxy stabilizes the wood and prevents further rotting

Note- in the original part... it does little or nothing to stop leaks
and prevent further rot around the margins of the saturated area!

.... but it has much lower
tensile strength than the wood and is considerably less resiliant. Unless
the part is reinforced with carefully aligned glass fiber it will not be up
to the task.


This correspnds exactly with my experience. I've seen mooring cleats
pull up out of rot-doctored decks which were hard as a rock from the epoxy.

When fresh out of the military and needing something to do, a friend and
I "restored" (or butchered, depending on who you talk to) an old classic
racing yacht. The planking was sound but the structure and deck was
spongy. We built a 6 point cradle with shaped frames, epoxy saturated
much of the interior structure, and laid up an internal truss mimicking
the original ribs & floors with some diagonals added. The boat had no
stiffness or strength in the hull until we added fiberglass cloth along
the truss members. After that, it was very strong & we raced the heck
out of it.

A few classic boat purists were upset at what we'd done, two or three
even threatened us. But the boat would have become a mulch pile and we
did this work in about 3 months instead of seven years to rebuild it the
"right" way.

YMMV

Fresh Breezes- Doug King