Subject: Sealing wooden hull
Date: Tue, 28 Apr 1998
Dear Doc Rot,
Thank you for the quick response regarding my problem. The entire inside of the hull below the waterline is moist however there are a few spots that are more wet than moist. It doesn't appear to be an isolated seam or leak. I would estimate that we get between 10 and 15 gallons of salt water in the bilge per week. It's interesting to note that we seem to get a lot more water in the bilge immediately after having the hull cleaned every other month. After a week or so it seems to go back to being moist. There is no fresh water coming in from topside.
The boat stayed out of the water two and one have weeks during So. Calif hot weather. When we launched, it severely leaked for several weeks. Upon re-launching , the boat yard applied Z-spar splash four places on the hull. This was done because the water was actually gushing in from between the planks.
The splash did its job and stopped the leaks. I also checked the stuffing box for excessive water leakage with negative results. When we hauled out the bottom was taken down to bare wood, I would estimate that between 25 and 30 coats of old paint were removed. We anticipate painting with a modified epoxy base bottom paint.
The hull construction is strip planked (edge nailed and glued) hardwood (Jarrah) approx 1.2x2". The fasteners are bronze anchorfast boat nails.
Thanks again for your time and expertise.
Right. I suspected and you have confirmed that the problem is probably
that your glue joints are failing. This is not the disaster it might
seem, since one assumes that the planks are well-anchored. It stops
leaking before hull cleaning because the slime that accumulates plugs
the seams somewhat. All wood boats do this.
You have 3 ways to go from here. The first is the easiest, and is what I
would try first and see how well it works. It is simply wooding the
bottomsides, letting it dry out for 5-7 days, and then applying 2-3
coats of our Clear Penetrating Epoxy Sealer (CPES) to the bare wood.
Finish off with a good, hard epoxy-base bottom paint. The 1st coated of
CPES should be applied carefully enough to allow as much of the CPES as
possible to enter the seams, the 2nd coats a little less carefully but
again concentrating on the seams. I'd probably follow up with a 3rd coat
just to the seams. CPES is not really a *filler*, except in tight,
narrow spaces, which of course is exactly your situation. And the hard
bottom paint will help.
The 2nd choice would be again to taking the bottom down to the wood,
going through the CPES sequence, and then over that applying a layer of
epoxy resin, such as our Laminating & Layup Resin. Much more expensive,
but will basically sheathe the hull in epoxy.
And your third choice is to go through the CPES routine again and cover
the exterior of the hull with a thin epoxy/glass cloth layer. This will
work absolutely (if done correctly) but again more money and lots more
Leave the inside of the hull alone. Do not coat it with anything. It
will allow the wood to *breathe*.
My guess would be about 4 gallons of the CPES for your 36' hull. Kind of
hard to tell because one never knows how much of the CPES the wood is
going to absorb, and you want to give it all it will take (keeping an
eye out inside to make sure it isn't just going into the bilge!). If you
need more California is not that far from Seattle and we can get it