Keel fairing, templates etc

This is a copy of an email I rec'd from Frank Fletcher. Some interesting info. Thanks for sharing this Frank.

"I have now got Voila on a trailer at home and have begun working on
her trying to maximize her hull speed potential. I just completed
removing 25 years of bottom paints, sanding primer/sealer, etc. What
a job! I hope this is the last time I ever do this
kind of work. Of interest was the keel.

I purchased the offsets and drawings from Farr and made up the
templates in a style I have used before and began the process. I was
suspicious of the keel's shape as I knew it had received substantial
work about 10 years ago in Vancouver where the yard did not use
fairing templates, and using some large make-shift dividers found
that measuring points were not in sync with the offsets. In my
method of doing this I start with a "full" template at the top
station, which in this case I used the top of the lead. Naturally
the template would not make it up to that point, leading me to start
grinding. I finally got it to fit just about perfectly where it
belonged. In doing this, I discovered that the keel is a wonderfully
cast piece of lead, with very minimal deformation. There was
possibly a small expanded area at about the 50% rear of leading edge
area in the top third of the keel, but once that lead was trimmed,
the template fit snugly into it's measuring point with no more that
about .5mm gap, and that is about as accurate as I was able to make
the template from 3/8 ply. The template/plate I made to fit up
against the bottom of the keel was also a nice match once all the
fairing putty, bondo, etc, that had likely been added by several
different people, owners, and yards, had been removed. I then worked
with a stiff straight edge working between the 15 per side measuring
stations and there was almost no daylight against the straight edge
once "all" filler was removed. This means that the lead is very
accurately cast to it's design and so for the most part, fairing this
keel to specification has meant filler removal.

I have had to fair out the toe of the keel which no doubt has hit
numerous rocks in 25 years, resulting in yard's grinding away the
smashed bits and smoothing them out with bits of filler, etc, and the
same with the very bottom tail on the trailing edge which I suspect
had been damaged and trimmed because it had about a 2" radius on it
instead of being square. But mostly, anything others did to this
keel during the boat's life has only detracted from the original keel
design.

For any members talking about truing their keel, I thought my own
experience might be interesting and was going to post it but could
not log on.

As the boat it going to be dry sailed for a while, I have decided not
to put anything on the bottom and am going through the long root of
sanding and bringing up the original bottom gel coat after using #80
grit. We used stripper to remove 95% of the VC17 and others, and
then used 80 grit alternating between flat sanding with a 6" random
orbital and a 16" straight in-line sander. After the 80, which got
me down to the gel coat, I have manually long boarding starting with
120, 220, 320, 400, and then machine polishing.   Hoping to be able
to skip the 320, but will see when I get there. Obviously I will
have to prime and re coat the keel and rudder. No doubt spraying after the 80 grit with some performance
bottom paint would have required much less effort, but I'm into it
now. My shoulders, back and neck are screaming and I won't need to
go to the gym for a while"





Edited by Bill Layton - 07 September 2009 at 3:32pm