[C320-list] Masthead Sheaves on Older Models

[Scott Thompson]

David:  The Catalina 320 Standard Mast Handbook that you mention does 
not appear to be on the Charleston Spar (now Sparcraft) web site.  But 
it is still available on the C320 Association web site.  You can find it 
here:

http://www.catalina320.com/filemgmt_data/files/Catalina320_Standard_Mast.pdf

I suspect that the two middle sheaves (not even visible unless you take 
the masthead cover off, apparently) were intended for spinnakers with 
the halyards exiting above the two rollers that you mention, and run to 
blocks on a spinnaker crane from there.  But I'm speculating about this 
and don't really know if that would work.  The OC 1 description on the 
Sparcraft website does say that this masthead supports a main halyard, a 
main "lift," 2 genoa halyards AND 2 spinnaker halyards.

David J Gleason wrote:
> 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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-- 
Scott Thompson
Surprise, #653