Shroud tension

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Michael Weeks

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May 12, 2022, 12:26:27 PM5/12/22
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I've got a 1976 P30. I want to tune my shrouds with a Loos gauge, I can't find a chart or the manufactures suggestion. Does anyone have that information, Dan?

Jeff Griglack

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May 12, 2022, 1:07:02 PM5/12/22
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As far as I know, Pearson never released a guide for use with a Loos gauge.  However, standard rigging books will tell you that, once you adjust the mast true and straight, you should adjust the uppers to about 15% of breaking strength, and the lowers should be adjusted to about 12% of breaking strength (though I would look that up).  The Loose gauge has a chart on the side telling you what those values are for your size of wire.

A friend recently gave me a Loos gauge, and I used it to tension the rig on my P365 this year.  Until now, I had never used one.  What I would do is tension things til I thought they were good, then go for a sail.  On each tack, I would take the slack out of the leeward shrouds.  It worked well for me for years.

Jeff
------------------------------------------------------------------
| Jeff Griglack             "Jabberwocky" P-365 #269
------------------------------------------------------------------
| "Don't take life so serious, son, it ain't nohow permanent"
|                   - Walt Kelly
| 'Years ago my mother used to say to me, she'd say, "In this
| world, Elwood, you must be" – she always called me Elwood –
| "In this world, Elwood, you must be oh so smart or oh so pleasant."
| Well, for years I was smart. I recommend pleasant. You may quote me.'
|               —James Stewart as Elwood P. Dowd
------------------------------------------------------------------


On Thu, May 12, 2022 at 12:26 PM Michael Weeks <mhilto...@gmail.com> wrote:
I've got a 1976 P30. I want to tune my shrouds with a Loos gauge, I can't find a chart or the manufactures suggestion.  Does anyone have that information, Dan?

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Michael Cyr

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May 12, 2022, 1:57:39 PM5/12/22
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I have a Loos for my 1970 P33-1 but I now pretty much do what Jeff does.  There are a few factors to keep in mind

1. Backstay tension affects mast shape and therefore sailing
2. Higher resting tension on the shrouds reduces cycling differences (as you tack) and therefore metal fatigue of shrouds
3. What effects do higher tensions have on hull and deck?

Mike in Maine
1970 P33-1 Brizo

George DuBose

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May 13, 2022, 2:14:05 AM5/13/22
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-------- Forwarded Message --------
Subject: Re: [pearson ] Shroud tension
Date: Fri, 13 May 2022 08:13:23 +0200
From: George DuBose <bo...@george-dubose.com>
To: Jeff Griglack <grig...@gmail.com>


This is a good topic.

I have a Loos gauge, but never tighten my stays and shrouds to the recommended tension.

I try to keep the furler/forestay from bending out of line too much and the leeward stays and cap shroud from moving in 20kts, but this season, I am going to put more tension on the fore and back stays to see if that keeps the door to the v-berth openable.

Nan Hall of Hall Spars gave me a tuning guide. Bill Shaw also created a tuning guide. But neither discuss the difference in tension between the forward lower stay and the aft lower stay. One should be tighter than the other, but my memory fails me.

Anyone know? I have attached some guides I have collected.

George/Skylark

On 5/12/22 7:06 PM, Jeff Griglack wrote:
As far as I know, Pearson never released a guide for use with a Loos gauge.  However, standard rigging books will tell you that, once you adjust the mast true and straight, you should adjust the uppers to about 15% of breaking strength, and the lowers should be adjusted to about 12% of breaking strength (though I would look that up).  The Loose gauge has a chart on the side telling you what those values are for your size of wire.

A friend recently gave me a Loos gauge, and I used it to tension the rig on my P365 this year.  Until now, I had never used one.  What I would do is tension things til I thought they were good, then go for a sail.  On each tack, I would take the slack out of the leeward shrouds.  It worked well for me for years.

Jeff
------------------------------------------------------------------
| Jeff Griglack             "Jabberwocky" P-365 #269
------------------------------------------------------------------
| "Don't take life so serious, son, it ain't nohow permanent"
|                   - Walt Kelly
| 'Years ago my mother used to say to me, she'd say, "In this
| world, Elwood, you must be" – she always called me Elwood –
| "In this world, Elwood, you must be oh so smart or oh so pleasant."
| Well, for years I was smart. I recommend pleasant. You may quote me.'
|               —James Stewart as Elwood P. Dowd
------------------------------------------------------------------


On Thu, May 12, 2022 at 12:26 PM Michael Weeks <mhilto...@gmail.com> wrote:
I've got a 1976 P30. I want to tune my shrouds with a Loos gauge, I can't find a chart or the manufactures suggestion.  Does anyone have that information, Dan?

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George DuBose
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Mobile: +49.160.481.1234
Skype: georgedubose or call +1.347.284.6443

Video interview on YouTube: https://www.youtube.com/watch?v=wcOxW65Xe10&feature=youtu.be

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HallRigTuneManual.pdf
Rig Tuning by Bill Shaw.pdf
UKHalsey rig tuning.rtfd.zip

Michael Weeks

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May 13, 2022, 8:07:40 AM5/13/22
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Those guides are fantastic, thank you!

On May 13, 2022, at 1:14 AM, George DuBose <bo...@george-dubose.com> wrote:


HallRigTuneManual.pdf
Rig Tuning by Bill Shaw.pdf
UKHalsey rig tuning.rtfd.zip

Michael Weeks

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May 13, 2022, 2:03:39 PM5/13/22
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Thank you folks. When I was out the other day I noticed my Leeward shrouds were very slack. I'm a newbie sailor so my tacks are rather harsh. I need to make sure I don't rip my mast out.

On May 12, 2022, at 12:57 PM, Michael Cyr <micha...@gmail.com> wrote:

I have a Loos for my 1970 P33-1 but I now pretty much do what Jeff does.  There are a few factors to keep in mind

Bill Robart

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May 15, 2022, 12:06:25 AM5/15/22
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I read thru the “Hall” article. Pretty good advice. I do have a small quibble. With the advice to tighten the shrouds as tight as possible using a 10” wrench. I don’t know how much tension that will generate but it sounds like a lot to me. I used a screwdriver that I’d guess was perhaps 7”” long.  I’d take that advice cautiously. I’d hate to see a boat damaged using a system where the users range from 90# weaklings to Olympic weight lifters.

I always used the “eliminate the slack” method and never had any damaged rigging and the boat sailed just fine.  

I recall reading about a couple of racers in an offshore race from Florida poking their masts thru their hulls from excessive headstay tension and choppy conditions in the Gulf Stream.  

Bill


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