On Fri, 10 Jun 2005 04:23:57 +0000, Bill McKee wrote:

One piece is much better. Those joints in the wood have little strength.


I don't think the joints in the core NEED much strength. I mean, you can
use Styrofoam as a core, and that can be broken easily by hand. Also,
balsa core is not very strong laterally, but it is an excellent core
material (unless it gets wet).

With cores, the important thing is that it adhere well to the skin, and
that it have good compression strength. Butted plywood with, say, epoxy
filler at the joint, should make a good core.

But then I am not a mechanical or structural engineer or naval architect,
so take my opinion for what it is worth.

--Mac


"Chris" wrote in message
...
So replacing wood with new plywood means I can cut out a shape of any size
and replace it with a close to equal piece of plywood correct? Just glass
the old plywood to the new plywood, right? No concern over how big a
piece of plywood is, etc? I could use two pieces of plywood for one hole?
etc


It appears I've got more rot than I had expected (although the transom
feels strong otherwise).

I've pulled out about a 1 foot x 1 foot section around the drain plug and
am evaluating whether there will be anymore to go too.. Have drilled a
bunch of holes in the lower inner part of the transom to see how far it
spreads and allow all the wood to dry up before my final decision



wrote in message
ups.com...
It's too late to do any more than slightly slow the problem by sealing
the exposed wooden surfaces of the drain hole.

If you like this boat and plan to keep it, you will want to cut the rot
out of the transom. Be sure to go a few inches beyond the point where
you "think" the rot ends when scarfing in the new piece. You should be
able to cut away part of the fiberglass on the outside of the transom
and spoon out the punky wood, cut a new piece of the best marine ply
you can find, and then glass up the exterior again.

This is a great chance to learn from the bad practice of the original
builder. Any hole drilled through a wooden member- transom, stringer,
etc for the purpose of draining water should have the edges sealed up
to prevent water from wicking into the surrounding area and promoting
rot. If it were my project, I would cut the drain hole large enough to
accept a drain plug with a bronze collar fitting. Seal the edges of the
hole with a layer of glass and resin, and then bond the bronze collar
into the sealed hole- perhaps using epoxy.

One rot gets a foothold, it is relentless. Transom rot on small boats
is fairly common, and as most are outboard powered it is double
trouble.