26S standing rigging tension

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BayouBoatin
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26S standing rigging tension

Post by BayouBoatin » Tue Mar 14, 2017 5:45 am

I have an X my buddy has an S. I noticed yesterday his standing rigging was quite loose. I searched for tension on the S uppers and lowers and could only find info for X's and M's (300 uppers 270 lowers...at least that's the consensus).

Does anyone know what the tension for the S is suppose to be? I tightened his but did it mostly by feel. I have a gauge and would like to get closer to where it is suppose to be. I would have thought similar but it seems his mast is a tad smaller than mine so I am not sure.

Thanks!

paul I
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Re: 26S standing rigging tension

Post by paul I » Tue Mar 14, 2017 6:22 am

The recommended tension is given in terms of % of wire break strength IIRC. If the wire is the same diameter, the tension should be the same too.

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Curwen
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Re: 26S standing rigging tension

Post by Curwen » Tue Mar 14, 2017 7:15 am

I have a 26D and have the same question. I haven't found a good resource for how much tension should be on the shrouds.

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grady
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Re: 26S standing rigging tension

Post by grady » Tue Mar 14, 2017 9:51 am

There is no good information on this. Tuning your rig is directly related to your sail plan/maker and the wind velocity. The more the wind blows the tighter you need your rig. I am still working on a tension chart for wind speed and sail choice. It is hard to build one when you are not racing one design and you have to go by seat of the pants performance. A good place to start is your outers should not slack at any wind below 12kts with the jib. It will slacken a couple of kts lower with the Jenny. I run my lowers loose because I have a adjustable back stay that is tightend in higer wind. That allows the mast to bend to flatten the main sail. (The sail was designed and cut for this). These tensions are similar to the other 2 26d's that sail also. One of them is one of if not the fastes D around "Wings". So keeping an eye on what he does is never a bad thing.

BayouBoatin
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Re: 26S standing rigging tension

Post by BayouBoatin » Tue Mar 14, 2017 11:52 am

Problem is these stupid stay adjusters are a pain to use when the mast is up. I have to use that tool that slides into both and then you pull down to make the adjuster go down some. He doesn't have turnbuckles. His lowers were so loose it was like a wet noodle.

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Tomfoolery
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Re: 26S standing rigging tension

Post by Tomfoolery » Tue Mar 14, 2017 11:55 am

BayouBoatin wrote:Problem is these stupid stay adjusters are a pain to use when the mast is up.
I use the MRS to lay it back a little, adjust, then pull it tight again to pin the forestay. That's after I adjust for mast rake with the forestay, that is.

But it's not something that has to be done very often at all, unless you're tuning for racing and wind conditions perhaps. But as the manual says, the lee shrouds shouldn't be too loose when heeled hard, whatever 'not too loose' means. :D

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grady
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Re: 26S standing rigging tension

Post by grady » Tue Mar 14, 2017 3:34 pm

That is why I converted to more traditional adjusters this year. Along with taking the tension off the fore stay get 2 awl's about the same diameter as the pin. A long taper helps also. you can use them to walk the tension up.

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Re: 26S standing rigging tension

Post by scomu » Mon Mar 20, 2017 1:46 pm

While on the subject, may I ask a bit more advice/lecture on shroud tensions. Having recently acquired a 26M and a newbie in sailing, I was disturbed by the less than straight mast which always turned to starboard. After adjusting lazybag's lines and loosening the shrouds, I now have a straight mast turning easily to eitherside. But the shouds are visibly loose! What is a practical gauge for shroud tension? I have the usual adjusters for the shrouds and a genoa with furler which cannot be adjusted as far as can see.

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Tomfoolery
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Re: 26S standing rigging tension

Post by Tomfoolery » Tue Mar 21, 2017 6:01 am

scomu wrote:While on the subject, may I ask a bit more advice/lecture on shroud tensions. Having recently acquired a 26M and a newbie in sailing, I was disturbed by the less than straight mast which always turned to starboard. After adjusting lazybag's lines and loosening the shrouds, I now have a straight mast turning easily to eitherside. But the shouds are visibly loose! What is a practical gauge for shroud tension? I have the usual adjusters for the shrouds and a genoa with furler which cannot be adjusted as far as can see.
Welcome to the forum. Pepperoni, please. :wink:

Most folks who measure stay tension are using Loos gauges, either the Professional style (PT-1 for the size wire rope on these boats), or the less expensive Regular series (90B for our boats). Amazon sells the PT-1 for $99 with free shipping (Prime), and DX Engineering sells them for $10 more with free shipping, if you don't have Prime. West Marine sells the cheaper one for the same price as the Pro model at DX, by the way, but it's a marine store, so there's that. :|

I don't know the exact tensions folks with M's use, but I think it's around 300 lb for the uppers, and (if memory serves) 270 for the lowers. Forestay is tensioned by the shrouds (uppers, primarily), as the forward force component of the fore stay is countered by the rearward force of the upper side stays, which are swept back. There is no backstay, so it's all on the shrouds. There is a turnbuckle inside the roller furler drum assembly for adjusting the mast rake, but that's all you can do with it.

The lower shrouds are mainly for stabilizing and supporting the mast column, and for allowing some bend in the mast as the forces in the swept-back spreaders are trying to push the middle of the mast forward.

Minimum breaking strength on 5/32" 1x19 302 SS rope is around 2800 lb, so that's a bit more than 10% preload on the uppers, and a bit less on the lowers. It's not unusual to go to 20% on shrouds for a fractional rig (in general), but I don't think that's necessary. They should be tight enough that they don't go slack when pushed hard.

These aren't racing boats (though the 26 classic pretty much is), so I just go for a stable rig and repeat-ability. I don't worry about precise tuning to the sail and wind conditions because my boat is a station wagon (or Waterbago, really), and it has the original blown-out sails, so no matter what I do, they're not going to perform any better and a bed sheet. :P

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Re: 26S standing rigging tension

Post by paul I » Tue Mar 21, 2017 8:27 am

I agree with everything Tom said in the above post. I have a :macx: not a :macm: , but I cant see why the tensioning process would be any different. I used the PT-1 Loos gauge to set mine as well. I got it done in a long afternoon, with the boat on the trailer. I ended up with all tensions falling between 300 and 250 lbs and a reasonably straight mast (as determined by eye while looking up from the base of the mast). If all the paired stays are the same length (as they should be), it is best to adjust them as a set. I also re-checked with the boat in the water and found little if any variation.

Be advised that when you make an adjustment on any pair of stays it will affect the tension on the other pair. So be prepared to:
1. measure the tension on the shrouds
2. lower the mast slightly using the MRS
3. make any needed adjustment to the plates
4. raise the mast using the MRS
5. attach the forestay and slacken the MRS
6. re-measure the tension on the shrouds

Rinse and repeat until you hit your numbers. You cant measure tension on the forestay with a furler, and there is no need to.

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Re: 26S standing rigging tension

Post by scomu » Wed Mar 22, 2017 1:18 pm

I appreciate the info and acceptance of my newbie entry. As a sailor in the fate-driven part of the World, exact measures and adjustments with a Loos gauge etc will be a big leap for my boat. But I admire knowledge-driven life style :wink: . Until an appropriate gauge is available to me, can one suggest a simpler "measure" for the tension, e.g. applying some weight vertically and judging the shroud's slack visually?
I would also love to read a bit about the math of weights and breakage limits of the shrouds. Please refer me to a site, if one is remembered off-hand.

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Tomfoolery
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Re: 26S standing rigging tension

Post by Tomfoolery » Wed Mar 22, 2017 1:46 pm

Any stainless steel wire rope source will have this info, but West Marine is easiest since they only carry stuff applicable to sailboats. Minimum guaranteed breaking strength is listed, but they aren't showing weight per foot. https://www.westmarine.com/wire

But their supplier is Alps, and you can download a catalog here. http://alpswirerope.com/catalogs/ But any marine rigging supply should have this info.

Your rigging should be 1x19 construction (1 wire per strand, 19 strands per rope), and likely 302/304, but the strength isn't much different from the more expensive 316 stainless rope.

As to preload tension, adjust the uppers so that they don't go slack on the lee side when heeled in a stiff breeze. The lowers shouldn't either, but that's hard to say as I adjust mine for a little bit of bow (forward) on the mast, which makes them a little looser than the uppers to start with, and I'm not usually paying as much attention to them. Remember that whatever you do to one shroud, you have to do to the other (once the mast is plumb and straight), because if you add more preload to the port shroud, half that adjustment will go toward tilting the mast a little, and the other will experience the same increase in preload. So do the same to both so you don't knock the mast out of plumb (side to side).

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tlgibson97
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Re: 26S standing rigging tension

Post by tlgibson97 » Mon Mar 27, 2017 4:08 am

I'm going to jump on this thread instead of creating new.

I just replaced all the rigging on my X and spent half the day trying to get it tensioned correctly without having too much bend in the mast. I have the forestay set. Backstay slack. Then I pretensioned the upper shrouds to set the slight bend I wanted. Then I tensioned the lowers to lock in that bend. Then gradually raised the tension to shoot for around the 300/270 number I see everywhere.

The problem I run into is it seems that I need more tension on the lowers to keep the mast from bending too much. I even set the lowers to about 300lbs with the bend I wanted but when I raised the uppers, it created too much bend.

What steps would you all take to reduce the bend in the mast? I read somewhere that you could go as high as 15% breaking strength on the uppers and 10% breaking strength on the lowers. On 5/32 wire that's 335 on the lowers and around 500 on the uppers. I don't thin I want to go that high but I figure anywhere between there and the 270/300 number.

No matter what I try, I can't seem to get the correct bend without having the lowers tensioned more than the uppers. I haven't read anywhere where that would be correct.

I could use any help. Thanks.

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Re: 26S standing rigging tension

Post by paul I » Mon Mar 27, 2017 4:20 am

I assume the bend you mention is fore-aft. Won't tightening the forestay remove some of the mast bend? Are you struggling to pin it in place? It should be somewhat difficult to pin when its all set correctly.

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Re: 26S standing rigging tension

Post by K9Kampers » Mon Mar 27, 2017 4:43 am

...or you can try the Peaches' Rigging Gauge...

Image

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