[C320-list] Masthead Sheaves on Older Models

[David J Gleason]

Two years ago I replaced the sheaves at the mast head on Proud Mary,
#150, 1994 vintage.  Scott is correct in that the sheaves are Acetal
(plastic).  However he did not go into the details of what needed to be
done beyond removing the instrumentation at the top of the mast.  The
masthead is the OCI shown on their listings.  There are six sheaves, 4
are 50 x 14. two are 60 x 14 plus there are two 10 x 16 x 15 rollers. 
The sheaves and rollers are set on straight pins that slide into groves
on both sides of the masthead.  In order to remove the straight pins,
they have to be lifted out of the mast head with both the sheaves
attached.  This prevents anyone from going up the mast on anything
attached to the mast head.  I believe it is necessary to un step the mast
to accomplice the replacement.   I was able to print out a detail diagram
from Charleston Spar titled "Catalina 320 Standard Mast Handbook" some
years ago.  I am able to find it again, at:
http://www.charleston-spar.com/us/technical_support/technical_brochures/m
astheads/fichiers/masthead_ocean.pdf   I hope this helps explain the
details of what is involved in the replacement.  I had ordered the parts
from Philip Polland at 704-597-1502, ex 767, ppollard at crowleys.com  in
September, 2007.  I note their phone number has changed.  Their current
web site: Crowleys.com gives 773-221-9990.  It might be wise to try to
old number first to see if still active.  Now, if anyone can tell me how
the two middle sheaves and rollers are used, I would certainly appreciate
it.  I only run a main halyard and messenger from the aft sheaves, a jib
halyard and spinnaker halyard from the forward sheaves.  I do not have a
spinnaker crane.

Dave Gleason
Proud Mary, #150


On Wed, 10 Jun 2009 23:58:02 -0400 Scott Thompson
<surprise at thompson87.com> writes:
> Looking at the mast manual from Charleston Spars on the Association 
> web 
> site it looks like the sheaves are "Acetal."  They are not all the 
> same 
> size.  Of course I don't know whether that applies to early boats, 
> but 
> the pictures in the manual look just like my 1999 boat's masthead.  
> The 
> design appears to require you to remove the mast head cover in order 
> to 
> remove the sheaves.  The masthead cover is the black insert in the 
> top 
> of the masthead in this picture:
> 
>
http://www.catalina320.com/mediagallery/media.php?f=1&s=20081116101601205
> 
> Of course if you have the usual array of windex, wind speed 
> instruments, 
>   anchor light, antenna, etc. as in the picture then you will have 
> to 
> remove some of that first because it will be in the way and maybe 
> even 
> blocking access to the masthead cover.  So once you are up there 
> (and I 
> mean WAY up there to get access to the top of the mast) you get to 
> remove all of that hardware.  Don't drop any of course.  Nor any of 
> the 
> mounting screws.  Then you get to remove the masthead cover (and 
> more 
> screws), and finally figure out how to get the sheaves out with the 
> 
> weight of the halyards on them.  (Don't forget to not disconnect the 
> 
> halyards holding you up.  This is going to require switching 
> halyards at 
> some point if you want to replace all of the sheaves.)  Then put it 
> all 
> back together.  No problem.
> 
> Personally, I find changing a lightbulb up there to be a challenge.
> 
> Scott Thompson
> Surprise, 653
> 
> 
> warren updike wrote:
> > I'm sure someone with a 1994-5 model knows what kind of sheaves 
> there are at
> > the mast head.  I think the choices are plastic like those at the 
> boom end
> > or some other more durable material.  
> > 
> > I was planning on un-stepping the mast last fall; but, the market 
> changed my
> > plans as it did for many others.  I'm also wondering if replacing 
> the
> > sheaves is doable from a boson's chair?
> > 
> > Warren & Pattie Updike
> > Catalina 320, #62, "Warr De Mar"
> > Middle River, Chesapeake Bay
> > 
> > 
> > 
> > 
> 
> -- 
> Scott Thompson
> Surprise, #653
> 
> 
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