Adjustable Leach

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Interim
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Adjustable Leach

Post by Interim » Thu Sep 08, 2016 1:17 pm

I just discovered that I have a line on the leach of my main that is adjustable.

I have a 94s, with what I think are original Doyle sails. This line goes through something like a tiny jam cleat about a foot from the clew. The question, of course, is what is it for?

Does shortening it make a fuller sail, and easing it make a flatter sail? It appears so, but I don't really understand when and why I would adjust it.

--john

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RobertB
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Re: Adjustable Leach

Post by RobertB » Thu Sep 08, 2016 1:19 pm

Don't worry about it, that is for the 1% of the Mac owners that actually know how to sail :P

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sailboatmike
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Re: Adjustable Leach

Post by sailboatmike » Thu Sep 08, 2016 3:53 pm

Here you go, read to your hearts content about the leach control line and how it adjusts sail shape

https://stingysailor.com/2014/11/27/lee ... olution-2/

Interim
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Re: Adjustable Leach

Post by Interim » Thu Sep 08, 2016 4:28 pm

Thanks, Mike.

Just what I needed.

--john

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grady
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Re: Adjustable Leach

Post by grady » Thu Sep 08, 2016 5:55 pm

Did not read the link but the cliff notes version..... loosen it all the way. When the leach flaps tighten it until it stops. End of story.

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Judy B
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Re: Adjustable Leach

Post by Judy B » Thu Sep 08, 2016 7:37 pm

grady wrote:Did not read the link but the cliff notes version..... loosen it all the way. When the leach flaps tighten it until it stops. End of story.
Ditto what Grady said. It's only there to prevent leech edge flutter, which causes the sail to rip just forward of the leech tape. It's best to leave the line loose unless the leech tape starts to flutter rapidly, making a "motoring sound". If the leech tape starts to flutter, tighen it only just barely enough to prevent edge fluttering. The motoring sound is from bending the cloth hundreds of times time per minute, and it inevitably causes the threads in the cloth to break.

It is not, contrary to what Stingysailor wrote in his blog, used to shape the sail. Do not use it to "cup" the edge of the leech. You want the leech of the sail to be as flat as possible, with smooth flow off the leech.
Last edited by Judy B on Sat Sep 10, 2016 11:17 am, edited 1 time in total.

Interim
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Re: Adjustable Leach

Post by Interim » Fri Sep 09, 2016 10:15 am

Thanks Grady and Judy B. I gather this is not an adjustment one uses depending on the conditions, like an outhaul or cunningham. I should set it to eliminate leach flapping, and leave it alone.

--john

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Tomfoolery
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Re: Adjustable Leach

Post by Tomfoolery » Fri Sep 09, 2016 10:36 am

Interim wrote:Thanks Grady and Judy B. I gather this is not an adjustment one uses depending on the conditions, like an outhaul or cunningham. I should set it to eliminate leach flapping, and leave it alone.
On the rare occasion I've bothered to loose mine, on several boats over time, and readjust when the flapping starts, it always ends up back in the same place, based on the dirt mark. :|

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seahouse
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Re: Adjustable Leach

Post by seahouse » Fri Sep 09, 2016 2:04 pm

A bit more info on the leech adjustment here, half way down the page…

http://www.macgregorsailors.com/forum/v ... lit=+leech

- B. :wink:

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grady
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Re: Adjustable Leach

Post by grady » Fri Sep 09, 2016 2:08 pm

Interim wrote:Thanks Grady and Judy B. I gather this is not an adjustment one uses depending on the conditions, like an outhaul or cunningham. I should set it to eliminate leach flapping, and leave it alone.

--john
Yes the more the wind blows the tighter you need to make everything.

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