Tanzer 16 keelson repair
by Lawrence Miller
Here is a set of photos I took
while I was rebuilding the mast step on my T16.
I've always been too lazy to cover the boat when I put it back in the driveway,
and every little place water can get into wood it does. then can't evaporate enough
to keep the wood dry. My mast had worn through the fiberglass on top of the keelson,
and I'd put more glass cloth on it several times. While the wood was still sturdy
enough, I put a piece of Corian countertop material on there to help the mast slide
easier, but didn't do what I should have to keep water out.
I happen to have a nice air compressor in my garage, with some air tools my son
had when we were restoring cars, so this was easier than it would have been otherwise
at the time. There's a new tool called a "Roto-Zip" by Bosch that I suspect will
do the work that needs to be done. I used a cutoff wheel to cut away most of the
fiberglass that was surrounding wood that was rotted, but made sure to leave a solid
"pocket" to hold the new and fiberglass to. I used whatever scrapers, picks, chisels,
etc. it took to get the old wood out, then let it dry under a heat lamp. The new
piece of wood is treated 3/4" plywood, I think, cut and slipped into the "pocket".
If I had to do it again I'd soak the new plywood with CPES (clear penetrating epoxy
sealer, from Rot Doctor Home Page.
Once it was in, I put about 4-5 layers of fiberglass matte over it, rolling it out
with a fiberglass roller.
I only use West System Epoxy Resin, but I hear MAS brand is just as good and less
expensive. Epoxy is about 30 times as strong a bond as polyester resin, especially
when attaching to cured polyester, which is what Tanzer used (it's much cheaper).
As you can see from the pictures, my boat was built flimsy enough that I've had
to reattach the seat tanks to the floor (and to the hull sides since). I haven't
done the one thing I need to finish the job(s), which is to paint over all the cured
epoxy resin. Epoxy deteriorates and gets brittle with UV exposure.
Everybody reminds me to use adequate respiratory, eye, and skin protection while
I'm working with fiberglass, resin, and acetone, but I often "forget".
Except for the curing of the resin (about 24 hours), you should be able to do this
job in 4-6 hours, even if you've never done any fiberglass work. Gougeon Brothers
(manufacturers of West System) puts out a nice little "how-to" book, as does System
3.