MacGregor 26 - Shroud Tension

Sumner · Jan 13, 2014

Before we got a Johnson Lever...

http://purplesagetradingpost.com/sumner/macgregor2/rigging-24.html

.... I would pin the forestay and then turn the turnbuckle to tension the rig, but never then knew what it was but it was way tighter than pinning without the turning of the turnbuckle afterwards. Then I got the gauge and found out I still wasn't tensioning the rig all that much and should of been tightening the forestay even more with the turnbuckle.

With the Johnson Lever you can tension with the turnbuckle once and always come back to the same tension by just using the Johnson lever to pin and un-pin the forestay.

If you don't use the Johnson lever then I'd turn the turnbuckle and use the gauge to get the tension you want. Then mark the turnbuckle so you can get back there in the future once you loosen it to unpin the stay.

Sum

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justsomeguy · Jan 14, 2014

CarlosIsaza said:
Thanks Sum. The picture showing the Johnson lever is very helpful as I have been looking at this option too because it definitely would make life easier to pin the forestay. However, can you increase the tension on the shrouds by adjusting chain plates after the forestay is pinned. Is there a way to change the pin's location on the chain plates after the mast is raised or do I have to bring the mast down, change the pin location on the chain plates and raise the mast again, which is quite cumbersome? I assume there must be a way to change the tension on the shrouds without lowering the mast but I don't know how to do this and what would be the correct way of doing it?

You can use a couple of nail sets, or small screwdrivers to move the verniers in 1/8th-inch increments, usually.

You could also make or buy a leveraging device, where you'd lever off the adjuster that's adjacent, such as the one available here:

http://www.bwyachts.com

Sorry, but you'll have to search their products to find it...

Sumner · Jan 14, 2014

CarlosIsaza said:
.. However, can you increase the tension on the shrouds by adjusting the chain plates after the forestay is pinned? Is there a way to change the pin's location on the chain plates after the mast is raised, or do

As was mentioned, yes. but what a pain dealing with the pins and wingdings and for sure you wouldn't ant to do that on the water. I did use the screwdriver method to tune the rig the way I wanted it when setting up the Johnson Lever but then with the lever didn't have to readjust it.

Don't for get that besides setting the tension on the forestay the shrouds as also making the mast straight or putting a bend in it. I have ours at a rake with about the same tension in all the shrouds and forestay but don't put a bend in the top above the lower shrouds. Some do and leave it and others use that to there advantage under sail for better sail shape. We aren't that technical but if you want to optimize the sails while sailing look into that.

Do you have a furler or a hank-on sail? If a hank-on you could move to the Johnson lever very cheaply. If a furler you might put more money into it, but we felt that it was time for new standing rigging anyway as we were getting some problems like you?

Sum

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Erik V · Jan 14, 2014

The solution I have come up with to get the rig tensioned is to use the jib halyard attached to my boom vang (4:1) connected to the forward cleat. My boat is a M25 equipped with a CEI furler so once I have the tension where I want it is easy to attach the furler head stay to the chain plate. I did up grade the jib halyard block to take the strain. Works fine for me.

Erik

Justin_NSA · Jan 16, 2014

I've said this before, if you try to adjust the shroud with a gauge like Loos to the correct tension for the shroud thickness, it will split the BWY tool. I know, I've done it. On a Mac, the gauge is really only good for equalizing the port and stbd tension. I would recommend following the steps on the BWY site and ignore the shroud thickness specs.

justsomeguy · Jan 16, 2014

CarlosIsaza said:
Thanks justsomeguy, Sum and Erik. I checked the parts in www.bwyachts.com as justsomeguy suggested and they have a "CUSTOM MADE LEVER STYLE TOOL TO ALLOW QUICK AND EASY ADJUSTMENT OF SLIDING SHROUD (STAY) ADJUSTERS WITH THE MAST UP AND TENSIONED". This seems to be exactly what I am looking for but it doesn't look very straight forward how the tool would be used. Has someone used it (or a similar tool) to adjust the shrouds tension? From my little experience, setting properly the shrouds tension will make a difference but getting the tension up to the #300 lbs is not easy. My boat has a furler so I cannot adjust the forestay's turnbuckle easily and definitely the Johnson lever is a plus to have.

I made my own. A 1" x 1" piece of stout hardwood about 2-3 feet long, a couple of small 1.5" carriage bolts that'll fit through the shroud's male adjuster holes, and a couple of wingnuts to hold the bolts fairly tight to the adjusters.

The carriage bolts emerge from opposite sides of one end of the wooden lever, and are spaced the distance (fore and aft) between the upper and lower male shroud adjusters, i.e., just a few inches apart.

Leaving one shroud adjuster fixed, you'll lever against it to tighten the other adjuster. HTH.

P.S.- Careful, you can easily overtighten them.

Erik V · Jan 16, 2014

I tension to 20% of the working load for 5/32 wire which is around 600# using the set up i mentioned in my previous post. When not sailing I relax the rig tension using the boom vang setup. My mast has a 1degree rake measured with the boat in the water and is straight. I have also set up the back stay with a 4:1 set up so when the wind pipes up I can bend it de powering the main. With a few other mods and a good suite of sails we can hold our own with some fast company. Its lots of fun giving them a run for their money.

justsomeguy · Jan 26, 2014

CarlosIsaza said:
I would like to tension the upper shrouds to 15% of breaking strength (450#) and 12% on the lower shrouds (400#) but I couldn't reach the tensions I wanted. I saw that the lever tool in www.bwyachts.com is now aluminum, which I guess is a problem with the tool breaking.

However, how is the tool used? Justsomeguy, do you have any pictures you can post?

Sorry, no pictures, but it seems pretty straightforward to me.

The end fitting on the tool is inserted into a hole on the male adjuster you'll lever against, and the fitting closest to your handle is inserted into a hole on the male adjuster you'll be tightening. This way, you can apply leverage.

I'll break out the big 'puter and draw you a picture.

justsomeguy · Jan 26, 2014

Whether the tool handle is extended forward or aft, depends on which shroud you're tightening.

In this example, you'd be tightening the shroud on the right. Downwards force is applied to the handle, levering against the fixed shroud on the left.

Chris & Lenore · Jan 29, 2014

Does anyone have the measurement of the distance between the two bolts? Id like to fabricate one but the boat is not close by to measure.

In the past, I used the Johnson lever to de-tension the rig. Once tension was off, I used the "marlin Spike" on my rigging tool to lever the two plates as required. There is always a hole that "almost lines up" that I can insert the tip of the spike into, then remove the cotter, then lever the plates to the next hole.

But the tool looks even easier!

Chris

justsomeguy · Jan 29, 2014

Mine's a couple hundred miles away, too.

But if a photo could help, here's one that should get you close enough. The male adjusters are about 5/8" wide, so maybe 2- 2.5 inches? Heck, 3 inches, and mount it slightly tilted up.
It's not crucial that the tool be level.

P.S.- NOT my boat!

chp · Jan 30, 2014

I have turnbuckles on mine. I just use some electrical tape around the threads to mark how much tension to put on the shrouds. When I lower the mast I loosen off the turnbuckles, use the jib halyard to hold the mast up, and unpin the forestay. Really easy and only takes as extra minute or so. Also makes it easy to tweak the rigging.

Doc_holiday · Feb 2, 2014

I also have turnbuckles on my Franken Rig. I don't worry about shroud tension too much and I am sure I will be blasted by the purists. They need to be tight but they don't need to play music. The forestay is the one and once it's adjusted, it tightens the others assuming they are equal. Making sure they are secure on the other hand is secure.

Last summer during the sippy cup, at some point after midnight, my port side lower shroud popped loose. Somehow the turnbuckle unscrewed and the shroud released. I jumped up on the deck and quickly reattached it. It occurred to me I had forgotten to put the locking wire in when I set the boat up on the ramp because of my running behind schedule. I tensioned it and put the wire in and we tacked a few times while I checked the others. It could have been ugly but all was good. I'm just glad one of my mates was awake to take the tiller.

Chris & Lenore · Feb 3, 2014

I have posted this before but if you have not read it, it's worth looking at.
It describes how to tune a fractional rig. Fractional is different than masthead in terms of proper tuning.

http://www.alohaowners.com/projects/rig/rig.htm

Chris

vizwhiz · Feb 3, 2014

Great article. Thanks for posting again.

MacGregor 26 - Shroud Tension

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