From: alanr@techbook.com (Alan Rosenfeld)
Subject: Summary: refairing J/24 keel
Summary: Summary of responses to posting
Keywords: keel J/24 fairing
Organization: TECHbooks of Beaverton Oregon - Public Access Unix
Date: Wed, 16 Dec 1992 18:09:10 GMT


The following is a summary of responses received from my posting asking
for comments relative to re-fairing a J/24 keel.  I am always grateful 
for the kind and knowledgeable folks who read and respond in rec.boats.

I've taken some liberties in summarization and paraphrasing for the sake
of terseness.  I apologize in advance if I offended anyone.

Alan Rosenfeld


From msolomon@mitre.org :

..." don't do it yourself unless your time is worth less than $2.50/hour."

"Some of the common errors I see people make include: fairing above station 
1 (a definite no-no since the structual
integrity of the sump can be comprimised), keel too thin in section 4,
and
more than +/- 5mm in trailing edge straightness.  Make sure you know
where
the keel is and don't put the trailing edge too far forward.  I would
get a
class measurer to show you how he measures your keel so you can make
sure
it comes out legal when you fair it.  After the keel is faired, you will
have to have the boat weighed to make sure you're not below minimum
weight"

---------------------

From zpope@osf.org

"Contact the J24 class association or J boats for the legal class
limits.
The keel can only be faired to the template chords and there are
restrictions on adding material to change the shape of the keel."

---------------------

From murphy@cytosine.phri.nyu.edu


  ..." We've been collecting advice from the people in our fleet who
  have done it, and the one major piece of advice seems to be to get a
  big
  grinder and just go to it, and don't worry about getting the keel a
  little too thin, because you can always build it back up.  Personally,
  I'd rather not take off lead from the keel and have to add weight
  higher
  up, so I'm inclined to be pretty careful with the grinding."

     "One thing we decided, based on the article in the Fall 92 class
     magazine, is not to bother moving the keel forward.  According to
     this
     guy (the owner of Computer Keels, don't remember his name), the
     only
     advantage to the far-forward keel is a little bit of weather helm;
     compared to shape and smoothness, it's almost irrelevant, and it's
     infinitely more work. "

     ---------------------

     From roy@mchip00.med.nyu.edu

     " ...don't automatically assume that just because somebody is a
     measurer, they will know anything about fairing keels.  Case in
     point: I'm
     a certified class measurer.  I've never faired a keel in my life.
     I've
     measured a few, but that doesn't mean I know anything about fairing
     them.

     Also, don't automatically assume that just because somebody is a
     measurer
     he knows the rules."

     ---------------------

     From bowers@rigel.dfrf.nasa.gov

     "There are two things I would say.  First, geta copy of "Sailing
     World"
     magazine, Jan 92.  There's a large article on setting up a J/24
     (includes fairing the keel.  Second, many studies have provenb that
     surface finish does little to nothing to reduce drag.  It is far
     more
     important, to get a fair surface, no bumps or hollows.  I have NASA
     tech reports on such if you need..."

     ---------------------

     From LIMS01.LERC.NASA.GOV!SEARO
     "Have it done by a pro!
		     Owner J/24 #3608"
		     ---------------------

-- 
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