[C320-list] Boom Vang Fitting

[Kenny Geist]

While putting the main sail back on today, I noticed that the triangular
fitting at the bottom of the boom vang where it attaches to the bottom of
the mast has bent about 30 degrees to starboard. Guess there was an
accidental jibe somewhere in her past.

My question is, should I take it off and have it straightened at a machine
shop or replace it as it might have been weakened. Also, will the solid
vang spring out when I loosen it from the fitting?

Thanks,

Kenny Geist
Ken...@Prodigy.net

WINDRIFTER # 317

[thar...@innovations-plus.com]

I think you should buy new. When you find it let me know. They will likely have the toggle and threaded pin I am looking for as well.

Ted hull 424

Sent from my iPhone

[Scott Thompson]

The vang will "spring out" a bit if it is under compression, as it will
be if it is supporting the weight of the boom. Lift the boom with a
halyard or topping lift first to avoid that. The vang will not come
entirely apart without some disassembly, so you don't have to worry
about it falling apart once you disconnect things.

I don't know whether it is advisable to straighten the piece out. I'd
consult Garhauer about that. However I would not bother to fix it
without a better understanding of why it bent in the first place. I
would be surprised if an accidental jibe was the cause. Regarding the
possible cause, years ago there was a thread on this forum (but I can't
find it in the archives) about a problem that Annie Bennett had on
Topcat, where that piece had been carving a little groove into the
aluminum casting on the mast that it is attached to. There is supposed
to be a protective stainless washer separating the two pieces so that
this could not happen, but on some boats the vang had not been assembled
properly and so the stainless "triangle" was allowed to rest directly on
the softer casting. Then rocking of the boat in the slip had caused
enough regular movement of the boom to gradually cause the triangle to
carve a little groove in the center of the casting. Eventually the
triangle caught in this groove during a jibe, preventing the triangle
from rotating properly on its pivot. In that case the resulting bending
moment caused a catastrophic failure of the vang. A picture of the
resulting damages is on the web site here:

http://www.catalina320.com/mediagallery/media.php?s=2008111610222652

If you look at the picture you can see the wear in the casting
underneath the stainless "triangle" piece. That's where the washer needs
to be. And there should be another one protecting the top part of the
casting also. That is, a washer should be immediately above and below
the "triangle" so that it will not wear on either the top or bottom part
of the casting. the lower piece is most vulnerable when the vang is in
compression, while the upper piece is most vulnerable when the vang is
under tension. Unless you

After I read about Topcat's problem and saw those pictures I checked out
the situation on my boat and found that indeed my vang was not properly
assembled either, and that the wear in the casting had started. I took
apart the vang fitting and move the washers to the proper location and
all has been fine since then.

Scott Thompson
Surprise, #653

[Kenny Geist]

Thanks so much Scott. Excellent commentary. I have Kevin at Catalina
checking for the part and now I have a thorough undersanding.

Best Regards

Kenny Geist
Ken...@Prodigy.net

WINDRIFTER 320

-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.5941 / Virus Database: 4342/9752 - Release Date: 05/11/15

[Scott Thompson]

Kenny, I remembered that there is also some useful reference information
in the Charleston Spar manual for our boats. (Charleston Spar made the
mast fittings including the pieces you asked about. The vang itself is
from Garhauer.)

See page 9 of the pdf at this link...

http://www.catalina320.com/filemgmt/index.php?id=49

Note especially the washer placement!

Scott

[thar...@innovations-plus.com]

I see the toggle part I need on page 8. Do you know where you can purchase this part?

Sent from my iPhone

[Larry Frank]

You can order them directly from Charleston Spar. I have done this twice
on my 1995 vintage 320. As for Scott's comments, I would like to know why
this has happened too. I credited an accidental Gybe too. I would
replace rather than fix because I have to believe the part is weakened and
will be further weakened during the fix.

Larry
WindSwept C320 #246

On 5/14/15, 6:55 PM, "thar...@innovations-plus.com"