Ballpark Tension (Loos Gauge) Settings for Rigging

[Kenneth K]

Anybody have a record of your Loos gauge settings for your standing rigging? While the absolute tension will likely vary between models and boat sizes, I wondered if the relative settings between say backstay, uppers, lowers etc might have some similar values in terms of % of tensile strength.

I'm getting ready to redo my wire-rope standing rigging and I just measured all the tensions before loosening anything up. Here's what I got:

Back stay (1/4"): 29 (guage reading) = 7.5% break strength

Fwd Lowers (7/32"): 21 = 6.5%

Aft Lowers (7/32"): 19.5 = 5.5%

Intermediates (7/32"): 16 = <4%

Uppers (1/4"): 32 = 9.5%

The upper shrouds (both port and stbd) were the biggest outlier on the high side, while the intermediates were almost off scale on the low side. Do these values look typical?

 

[peaman]

Are you aware that the Ericson manual includes a procedure for tuning the rig, which does not specify tensions per se, but does explain how to put it all in order?

 

[Dave G.]

My rigging is not exactly like yours so may not be a whole lot of direct correlation. I do use a loos gauge to check on tension from time to time. These are the last settings from last season. I also have a fractional double spreader rig so maybe tuning/tension may also be a variable.

Backstay (1/4") 28-7% (adjuster off), 34-11% (adjuster full on)

Fwd Lowers NA

Aft Lowers (9/32) I tune these under sail and just enough tension that they do not go slack in about 15 knots. They're also too big for my gauge.

Intermediates (3/16) 18-11%

Uppers (1/4") 36-13%

 

[Alan Gomes]

The late (and great!) rigger Brion Toss did a video I watched way back in 2002 called "Tuning Your Rig." I took notes on his presentation. Note that the boat I had at the time was a masthead rig, so there could be some differences. But for your interest, I'm copying and pasting the notes I took below:

Brion Toss Video Notes

Notes on “Tuning Your Rig” by Brion Toss

Stretch is proportional to length.

Stretch is proportional to load.

Wire has an elastic limit.

Leeward shrouds should never get completely slack

If leeward shrouds too slack then you will get shock loads when tacking. Hard on rigging.

When bending the mast with the backstay, the forward lowers will get slacker and the aft lowers tighten. Therefore, need to put a little extra tension on the forward lowers.

Lowers = 10-12% of breaking strength.

Intermediates would be 12-15% tension

Uppers 15-20%

Backstay same as uppers (at medium tune), 15-20%

Forestay same as backstay, 15-20%



Don’t over tune the backstay or the rig gets squirrely; hard to stay in column.

Start from bottom and work up, though it does not appear to be critical to do it this way.

Brion started by first detuning the rig. It is loose but not flopping around.

Do each side a little at a time if worried about distorting the mast.

If there is a bend in the mast then it could be caused by any number of variables. So back everything off again, make rigging loose but even, and start over.

He tunes the backstay last. So initially it would be set just as the others are.

Biggest flaw in tuning is making the backstay too tight.

Says that on a rig like mine (i.e., masthead rig, 2 lowers, no baby stay) you can’t and don’t really want to bend the mast.

 

[Kenneth K]

Thanks for all the helpful responses. Sounds like my intermediates were too loose. I'll fix that during the re-rigging.

Apparently, that Brion Toss video is still available on DVD from Amazon. Maybe it'd be worth the investment since I'm doing the re-rigging on my own.

 

[bigd14]

The other day I stepped off the boat (30+ fractional rig) while grabbing the shrouds and and noticed that the mast pumped around when I let go. I moved around to the other shrouds and the headstay and backstay and could get the mast pumping pretty easily. I have tuned the rigging as per the guidance in this website but have not used a gauge. Last time I tensioned the rigging I thought I had it a little too tight (head door was binding) so I backed it off a little. I was also worried about the cracks in my bow area (https://ericsonyachts.org/ie/threads/help-crack-on-bow.18829/) so I de-tensioned the headstay a turn. When sailing the lee shrouds are reasonably tight as per the Ericson guidance. Tensioning the backstay does nothing to alleviate the issue (and I wouldn't expect it to on a fractional rig).

In the video the headstay seems too loose and you can hear the mast pumping. Is everything else too loose now? Would tightening the headstay tighten everything else up? Or is some mast pumping normal when shaking the rigging? Is this a problem with fractional rigs as opposed to masthead? I don't recall ever having this issue on the 27. Wondering what others experience is with similar fractional rigs.

Oh and I haven't fixed the bow cracks yet. If we would ever get a few days of sunshine I might be able to start in on it!

Thanks,

Doug

 

[G Kiba]

The other day I stepped off the boat (30+ fractional rig) while grabbing the shrouds and and noticed that the mast pumped around when I let go. I moved around to the other shrouds and the headstay and backstay and could get the mast pumping pretty easily. I have tuned the rigging as per the guidance in this website but have not used a gauge. Last time I tensioned the rigging I thought I had it a little too tight (head door was binding) so I backed it off a little. I was also worried about the cracks in my bow area (https://ericsonyachts.org/ie/threads/help-crack-on-bow.18829/) so I de-tensioned the headstay a turn. When sailing the lee shrouds are reasonably tight as per the Ericson guidance. Tensioning the backstay does nothing to alleviate the issue (and I wouldn't expect it to on a fractional rig).

In the video the headstay seems too loose and you can hear the mast pumping. Is everything else too loose now? Would tightening the headstay tighten everything else up? Or is some mast pumping normal when shaking the rigging? Is this a problem with fractional rigs as opposed to masthead? I don't recall ever having this issue on the 27. Wondering what others experience is with similar fractional rigs.

Oh and I haven't fixed the bow cracks yet. If we would ever get a few days of sunshine I might be able to start in on it!

Thanks,

Doug

I think the issue is that there are basically masts that are designed to bend and those that do not. Like you, I have moved from an E27 with an un-bendy mast to a boat with a bendy mast. Adding backstay pressure (up to 2500lbs) flattens and de-powers my main, prevents the mast from pumping, loosens the shrouds (a lot), and reduced whether helm. I think what is more important is that the windward shrouds do not allow the mast to fall out of column. And of course the mast pumping is reduced or stopped. I had a discussion with Scott Easom in Richmond when I had some work done at his shop. He's Roy Disney's rigger. He told me the mast will break if is allowed to bend backwards. Inducing an arch with backstay pressure makes the mast stronger. I don't like how loose my lee shrouds are but I also don't want to add much more tension on them. I think my Loose gauge setting are 46-49 on the uppers.

 

[Frank Langer]

Doug,
On my 1984 E30+ the shrouds are tight, but will start to feel a bit slack but not look at all slack in about 15 knot wind. My forestay is much tighter than your video, and my Harken manual says the forestay should be tight, but the jib halyard a bit loose to ensure smooth furling. With my setup I can't get the mast to pump by pushing on shrouds.
When I had my Headstay replaced last year the rigger was very pleased with my rig tuning and made no change to it.
Frank

 

[bigd14]

Adding backstay pressure (up to 2500lbs) flattens and de-powers my main, prevents the mast from pumping,

My forestay is much tighter than your video,

Thanks Grant and Frank. So my headstay is way too loose then. That might explain why tensioning the backstay didn't do much to stiffen things up. Come to think of it, the backstay didn't induce as much mast bend as normal. I'll tighten up the headstay and see how things look. Getting at the turnbuckle under the furler drum is actually quite a process. It requires removing the jib, then I have to rig a line all around the pulpit to hold the furler up followed by an awkward angle of attack with pliers to keep the wire stud from rotating all while trying not to fall off the dock. Another afternoon booked out...

Hopefully a tighter headstay doesn't cause any issues with the bow crack developing further or the head door binding (I'll bring a block plane). Guess we'll find out.

 

[Loren Beach]

One thing to keep in mind is that tightening the backstay directly tightens the forestay. Changing the length of the forestay will certainly move the mast and center of effort a little bit, tho.

 

[Dave G.]

FWIW, I hardily recommend the use of a loos gauge. I'm guessing a professional rigger can get it real close by feel and sound. I can tell you that tightening my rig with standard length open wrenches it's very difficult to over tighten with one hand. So I tighten everything up then stick the the loos gauge on it for final tweaks. 12-15% is my sweet spot range for shrouds and a little less on resting backstay as I have an adjuster. Backstay on our fractional rigs does not have much effect on tightening the headstay in my experience. Headstay is length thing for me as I want a slight rake aft in the mast.

 

[bigd14]

Thanks for the info guys. I got the headstay tightened up quite a bit today and gave the other stays a turn and the whole mast seems much more stable, with no head door binding. I can still induce some mast pumping by whanging on the lowers, but it's much reduced and with the backstay on nearly eliminated. The backstay also has much more of an effect on mast bend. I'll have to make final adjustments while sailing. I had a heck of a time raising the headsail into the furler luff groove by myself with a frisky breeze sending it twisting all around when I just needed it to sit still and behave.

 

[G Kiba]

Be sure to let off backstay pressure when hoisting and also when rolling up or out. Makes a huge difference on my boat. I do head sail changes by myself often. I put a single wrap of the halyard on the cabin top winch to bring the end forward to the bow where I can pre-feed the luff of the sail into the foil (or the pre-feeder) as I raise it.

 

[bigd14]

I put a single wrap of the halyard on the cabin top winch

Yes I run it back to the cabin top winch too. Unfortunately the halyard is small diameter Dyneema and slippery as heck so it won’t stay wrapped on the winch without some extra turns and temporary knots on anything handy nearby. I can winch a foot or two of it up at a time then a trip to the bow is needed to free snags and bends. Combined with lots of jumping the halyard at the mast. Seems like it takes me half an hour solo in calm conditions but it was a 45 minute workout yesterday with the wind blowing the sail away from the ideal hoisting position! I should just bring a helper but I’m kinda dumb that way.