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Bending the mast

Posted: Tue Jun 25, 2019 9:20 am
by Interim
My mainsail is a bit saggy from the luff to the chord. It is not luffing, just a bit untaught on a close reach.

It is a new sail, so this should be a matter of tuning the rig. I think I need to put a little bend in the mast to pull the belly forward and flatten it.

Is the best approach to tighten the backstay?

--john

Re: Bending the mast

Posted: Wed Jun 26, 2019 11:43 am
by THE CUSCUS
Is your backstay adjustable? most Macs aren't. Do you have a boom vang or Cunningham? Also, is your luff tensioned enough?

Re: Bending the mast

Posted: Wed Jun 26, 2019 1:45 pm
by Interim
The luff is tensioned enough.

I have a boom vang, used mostly for down wind, but have not employed the cunningham. (sail and mast are rigged; captain has been too lazy to go forward).

The backstay is not adjustable while underway, but the connection at the chainplate has multiple holes so I can change the length of the stay.

I'll try the cunningham this weekend and report back.

--john

Re: Bending the mast

Posted: Wed Aug 14, 2019 10:50 am
by Sisu
Easy enough to make your backstay adjustable, too - just cut it a few feet shorter, re-swage the eye, and add a 4:1 or 5:1 purchase in the space you just created. BWY also sells a kit.

Re: Bending the mast

Posted: Wed Aug 14, 2019 11:26 am
by Tomfoolery
Sisu wrote:
Wed Aug 14, 2019 10:50 am
Easy enough to make your backstay adjustable, too - just cut it a few feet shorter, re-swage the eye, and add a 4:1 or 5:1 purchase in the space you just created. BWY also sells a kit.
Or upgrade your main sheet fiddle block setup to ball bearing fiddle blocks (which BWY also sells, and which I own :) ), and use the old set for the backstay.

If that's not enough, use a single sheave block on the backstay, anchor one end of that line to the tang on the coaming, and use the 4:1 block and fall to the other end of the line. Voila! 8:1 backstay tensioner. 8)