[C38] taught head stay, then backstay tension

[Don Strong]

Mark:
   The winds are such that we go to weather when embarking on a sail 
from the east SFB. Before leaving the dock, I tighten the jib furler by 
means of the jib sheet led to port winch on the mast. If you don't have 
a furler, then you would perform this tightening when you raise the jib. 
Then I then put 1000lbs of tension on the back stay adjuster. This 
places more tension on the jib furler, which one can see easily in 
reduced sag and sway of the furled jib; 1000 lbs of tension gives a 
taught, furled head sail even in a seaway. The backstay tension greatly 
improves the performance going to weather. I echo the advice of your 
rigger. Too much backstay tension will bend the boat. It causes the head 
door to jam shut on Discreet Charm. 1000 pounds on the gauge of our 
backstay adjuster does not change the shape of the gap between the head 
door and the frame.
   When we head home, I release the backstay tension. This improves 
performance before the wind.  I release tension on the jib furler before 
disembarking.

Others on the list are much more accomplished sailors than me, and will 
give more sophisticated advice.
Regards, Don

On 6/25/13 10:12 AM, Ray Torok wrote:
> Adding to the discussion - If the forward lower shrouds are tight 
> and/or the mast is pinned at the partners, the backstay will impart 
> all kinds of mast bend, so I don't understand your rigger's statement.
>
> Ray Torok
> Thira #37
> San Francisco
>
>
> On Tue, Jun 25, 2013 at 10:06 AM, Mark O'Dell 
> <mixedbusinesscontact at gmail.com 
> <mailto:mixedbusinesscontact at gmail.com>> wrote:
>
>     Sorry that this might be a bit of a tangent, but Ray's question
>     below sparked another semi-related question that I have:
>
>     Last year I had my spreaders re-angled, my rig inspected and
>     tuned. (Ended up replacing the shroud extension cable that comes
>     through the hanging locker, as it was microscopically cracked in a
>     few places on the swauge).
>
>     Anyway, these people told me something interesting, in that they
>     said said we don't have a mast that will have much bend to it.. so
>     be very gentle with the backstay adjuster.  (They went so far as
>     to making me a limit indicator on the adjuster that "I shouldn't"
>     exceed. )
>
>     They're telling me that our masthead rig isn't really bending the
>     mast much at all... it's just pulling the mast down on the keel
>     step harder and harder.
>
>     I will also say that even if I exceed their "limit" my head stay
>     is still sagging more than I think it should. +6"
>
>     Do you guys go above 2k lbs of pressure? 3k? What you're setting?
>
>     Is my mast rake out of whack?
>
>     Mark O'Dell
>     Momentous #230
>     Baltimore, MD
>     http://www.c38momentous.com
>
>
>
>
>     On Jun 25, 2013, at 12:52 PM, Ray Torok <torok13731 at gmail.com
>     <mailto:torok13731 at gmail.com>> wrote:
>
>     > All:
>     >
>     > After repairing my lower spreaders, I have to retune the whole
>     rig.  Are there recommended settings for mast rake, pre-bend and
>     that stuff?  Also, is there a recommended tuning procedure
>     (several are out there on the internet)?  Should I remove the
>     Spartite plug at the partners to start?  I have no idea if the
>     original setup was okay.  In fact, without lots of backstay (and
>     mast bend), the headstay seemed awfully slack to me.  Any
>     thoughts/advice/experience would be appreciated.
>     >
>     > Thanks,
>     >
>     > Ray
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-- 
Donald R. Strong
Professor,
Department of Evolution and Ecology
and
The Bodega Marine Laboratory,
University of California, Davis,
Davis CA
95616
530 752 7886

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