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Backstay

Posted: Wed Jul 06, 2011 6:17 am
by mmason_az99
Ok, time to pick the brains of much wiser Mac people than yours truly ....

Here's my challenge; the backstay cable on my X is approximately 4 feet too short to reach the tiedown on the transom. There are no kinks in the cable, including at the top of the mast. In looking at BWY it appears they have a backstay adjuster that seems like it would work in that 4 foot space, any recommendations? The biggest mystery to me is how the PO had it set up in the first place. But therein lies the wonder and awe of owning a Mac .... tinkering :)

Re: Backstay

Posted: Wed Jul 06, 2011 7:07 am
by Bleakco
When I bought my :macx: I ran into the same problem.. The PO had never stepped the mast in 5 years and did not understand the short backstay either...Digging thru the gear box I came accross what looked like 2 boom vangs :? and the light bulb finally lit.....duh, one must be the backstay adjuster and lo and behold it fit and worked great!!! :D :D :D

Re: Backstay

Posted: Thu Jul 07, 2011 8:47 pm
by DaveC426913
My backstay is loose. I suppose if I hucked on it enough I could get one more notch in.

Does it need to be tight? At the moment, it will do little more than prevent the mast from pitching forward under high load.

Re: Backstay

Posted: Fri Jul 08, 2011 3:41 am
by Catigale
It really only serves function when running downwind. It can be a lot looser than the side and fore stays.

Re: Backstay

Posted: Fri Jul 08, 2011 6:13 am
by bscott
An adjustable backstay allows you to let the mast move forward for better sail shape going downwind and provide a more secure mast (harden up) when on a close reach and motoring at high speeds. A 4:1 vang is sufficient.

Bob

Re: Backstay

Posted: Fri Jul 08, 2011 2:47 pm
by restless
adjustable also means it alot easier to set the forestay!
We run a split inverted Y type... one of our best mods.

Re: Backstay

Posted: Sat Jul 09, 2011 1:05 pm
by ronacarme
See prior posts re purpose of backstay on an X.
1. Forestay and shrouds hold the mast up. Backstay is not needed for that.
2. Tensioning backstay induces mast bend to flatten main e.g. to reduce heel going to windward and close reaching in high winds. In light winds I leave backstay slack, to make main baggier for more drive, and to maybe induce a bit of heel to help maintain sail shape in light and fluky wind.
Ron

Re: Backstay

Posted: Sat Jul 09, 2011 8:03 pm
by mika
So, then, why is there no backstay on the "M"?

Re: Backstay

Posted: Sun Jul 10, 2011 7:04 am
by bscott
The :macm: rotating mast makes rigging a backstay very difficult. I have a :macm: mast on my :macx: and found a way to incorporate 2 backstays to facilitate mast rotation. In order to allow the mast to rotate freely I must ease the backstays full off prior to a tack, then harden up the new leeward stay once the rotation takes place.

If I'm solo, I rarely use the rotating feature. I am considering eliminating the rotation feature and pin the mast straight--it is a PIA to rig on the trailer without help.

Bob

Re: Backstay

Posted: Sun Jul 10, 2011 2:33 pm
by Catigale
The geometry of the spreaders and stays on the :macm: are quite different than the :macx:

The :macm: stays are much farther back and take more load of the mast from rear forces.

Re: Backstay

Posted: Sun Jul 10, 2011 3:14 pm
by mk1
DaveC426913 wrote:My backstay is loose. I suppose if I hucked on it enough I could get one more notch in.

Does it need to be tight? At the moment, it will do little more than prevent the mast from pitching forward under high load.
Yes, absolutely. But not always.

I have just installed backstay tension adjuster on my :macx: and I was surprised to see how much difference this makes even with modetare winds when sailing close to the wind. Some tension in the backstay really takes a lot of force out of the main and reduces heeling angle by 5 degrees or so.

I used a pair of harken micro blocks, 244 and 245, the whole thing is short enough so my original backstay did not need to be shortened. I saw this mode on this board, with these two blocks mentioned.