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post #31 of 42 Old 08-05-2015
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Re: Rig tension too tight?

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Originally Posted by L124C View Post
With the ridiculous tension the "rigger" put on the wires (remember, they were well off the 1/4" Loos chart), could this mean my new standing rigging is toast?
Could be; but, you'll have to 'politely' discuss with the rigger as the rigger is responsible for work done under his auspices.

Suggest you measure/record (and have witnessed) all the as-found tension measurements, etc., and before any such 'friendly' discussions -secure and document the 'evidence', if needed. Id also suggest to borrow a second Loos Gage. when you re-measure.

Better to 'make a deal' for any corrections than to early on give any hint of the possibility of 'litigation', etc. --- negotiate on a friendly basis if possible.
Written documentation on 'everything' - notes, pictures, videos, recorded lists, etc., for 'just in case'.
There's usually a simple solution/remedy to such 'problems' - negotiate on a 'friendly' basis, first. Save the adversarial stuff for later, if you 'really' need to - IMO.
:-)
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post #32 of 42 Old 08-06-2015
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Re: Rig tension too tight?

Agree with RichH above. But it looks like you may have only tensioned to 19% (1350 lbs/7100 lbs= 19%) if I got the numbers right. In which case you are well below yield, but do have much more than the required tension. So as RichH says, check you tensions again then do the math.
Good Luck

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post #33 of 42 Old 08-06-2015
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Re: Rig tension too tight?

48 on the 1/4" scale is pretty high, over the highest number 43 is 1800lbs. hard to say what the tension was. i would not have concern that the rig would come down because you are no where near breaking strength or it would have broken. the wire may have permanently stretched and is a little longer. in the Loos instruction it shows the 1/4" having a breaking strength of 8200 lbs and a forestay tension of 1300 to start. I would have discussion with the rigger and also see if you can use his Loos to check yours. if the loos 90 has been over stretched it will bend and show high readings. I would let him know that you are not happy with the way your boat was handled.

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post #34 of 42 Old 08-07-2015 Thread Starter
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Re: Rig tension too tight?

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Originally Posted by casey1999 View Post
Agree with RichH above. But it looks like you may have only tensioned to 19% (1350 lbs/7100 lbs= 19%) if I got the numbers right. In which case you are well below yield, but do have much more than the required tension. So as RichH says, check you tensions again then do the math.
Good Luck
I assume you are referring to the 1350 in my OP. Problem is, that's 1350 lbs on the 9/16" scale, not 1/4" (my rig). I have no idea how much tension was on the shrouds. In addition, due to the gusty conditions (10-30Kts) when I sailed back, the Starboard shrouds took some serious loads.

How would I know if the rigging was overloaded and damaged? I'm planning on re-tuning using the stretch & measure method, but would that mean anything if the wires had been overloaded?

Anyone have thoughts on post #30? I'm betting that's not good practice. Looked around the marina and don't see other boats with that much space on the pin.
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Re: Rig tension too tight?

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Originally Posted by L124C View Post
I assume you are referring to the 1350 in my OP. Problem is, that's 1350 lbs on the 9/16" scale, not 1/4" (my rig). I have no idea how much tension was on the shrouds. In addition, due to the gusty conditions (10-30Kts) when I sailed back, the Starboard shrouds took some serious loads.

How would I know if the rigging was overloaded and damaged? I'm planning on re-tuning using the stretch & measure method, but would that mean anything if the wires had been overloaded?

Anyone have thoughts on post #30? I'm betting that's not good practice. Looked around the marina and don't see other boats with that much space on the pin.
The loads during sailing do not add to the static loads. if the stacic load on the wire is 1000 lbs and the load during sailing is 2000 lbs then the wire has seen a 2000 lbs load. sailing loads will always be a lot higher then the loads at the dock if the wind pressure is high enough

spacer would be a good idea. each side of the fork is taking an uneven load

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Last edited by overbored; 08-07-2015 at 11:47 AM.
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post #36 of 42 Old 08-07-2015
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Re: Rig tension too tight?

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Originally Posted by L124C View Post
I assume you are referring to the 1350 in my OP. Problem is, that's 1350 lbs on the 9/16" scale, not 1/4" (my rig). I have no idea how much tension was on the shrouds. In addition, due to the gusty conditions (10-30Kts) when I sailed back, the Starboard shrouds took some serious loads.

How would I know if the rigging was overloaded and damaged? I'm planning on re-tuning using the stretch & measure method, but would that mean anything if the wires had been overloaded?

Anyone have thoughts on post #30? I'm betting that's not good practice. Looked around the marina and don't see other boats with that much space on the pin.
Yes I have the wrong numbers. For an estimate I looked at the scale on you Mod 90 Loos:

http://loosnaples.com/images/90b.jpg

It looks to me you can double the 9/32 inch dia load to get a rough estimate of your 1/4 inch loads (extrapolate the chart). I believe in you OP you said 9/16, but I think you met 9/32- correct me if I misunderstand. So the 1350 would convert to 2700 lbs on for 1/4 inch wire. Or about 38% of breaking. And note if you use 49 (instead of 48.5) on your mod 90 Loos scale you will be at 4,000 lbs on your 1/4 wire, which is 56% of breaking and your 1/4 wire probably has a small permanent stretch (it has "yielded" and should be considered "failed" and replaced"). You cannot use the stretch method of tuning as your standing rigging has yielded and has permanent deformation.

I also checked the above extrapolation by plotting the loos scale for 1/4 wire (scale number vs load) on graph paper and extrapolated that graph- the result of that was also about the same as the results above. So I believe the tension on the rig is somewhere around 3,000 lbs or 42% breaking strength.

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Last edited by casey1999; 08-07-2015 at 02:05 PM.
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Re: Rig tension too tight?

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Originally Posted by overbored View Post
The loads during sailing do not add to the static loads. if the stacic load on the wire is 1000 lbs and the load during sailing is 2000 lbs then the wire has seen a 2000 lbs load. sailing loads will always be a lot higher then the loads at the dock if the wind pressure is high enough

spacer would be a good idea. each side of the fork is taking an uneven load
I think if a rig is over tensioned, such that the leeward shroud does not go slack when the boat is at maximum heel, then the tension due to wind load will load up the windward shroud equal to the dock tension plus some wind induced tension. Say the OP's boat was tensioned to 4,000 lbs at the dock. He then sails in a strong wind with boat heeled 30 degree. The windward side shroud might see an additional 1,000 lb wind induced load in addition to the 4,000 pre-load for a total load of 5,000 lbs At the same time the leeward shroud would see 3,000 lbs load. Looking at this as a freebody diagram as used in static design, the torque of the keel will offset the torque difference at the mast. This is why, at max wind strength, the leeward shrouds should just go slack- this will require the lowest loads on the shrouds when sailing or at the dock.

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Re: Rig tension too tight?

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Originally Posted by L124C View Post
I sailed the boat from the yard (rigger) on a super gusty day. It seemed to sail fine, though it's hard to say given the conditions. My concern was not performance, but what appeared to be an excessive amount of tension on the rig (as per Loos). The rigger had a young guy that works for him tune the rig, and I find it interesting that the rigger never questioned that the rig was too tight in his response.

Guess I have to loosen everything and start from scratch. Not the end of the world, but not exactly what I had in mind when I paid a "pro" two grand for new rigging!

By the way, I tested my gauge on several other rigs around the marina and they tested within range for wire size. So the gauge seems OK.
During this sail did the leeward shrouds go slack or were they always super tight? This would give you a good indication if the reg were tuned too tight.

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post #39 of 42 Old 08-07-2015
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Re: Rig tension too tight?

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Originally Posted by L124C View Post
There is something definitely wrong with this rigger or the guy he has working for him. When I picked the boat up, I asked the assistant why he ran the backstay aft of the stern rail. He replied "Well, it touches the rail either way and that seemed like the best way to rig it.". Later, I noticed a 3/8" gap between the top of the chainplate and the stern, which led me to notice the backstay was bending over the top of the stern rail, essentially making it part of the rigging (with all the tension mentioned in the OP!)

The first pic shows the way the rigger had it. Not a great shot, but notice how the backstay deflects over the rail and you can only see half of the turn buckle. The second pic shows when I moved the backstay forward of the rail. I'm no rigger, but the second line is so much more natural and obvious, it's laughable! The backstay barely kisses the rail, and the chainplate is against the boat again.

Funny thing is...this rigger is well known, has a big shop, and I have no doubt he works on boats who's spreaders are worth more than my entire boat. I guess he just wasn't interested in my little project and delegated it to his assistant who apparently doesn't have much common sense.

This is not as serious as you (and others) may think.
Surprisingly low force is needed to move a string some little distances. Think about a guitar string, tensioned as it is, it is still easy to move it.
It really looks as the backstay should not touch the stern rail. So, yes it was not really correct mounted. But this doesn't make the stern rail to be a part of the rig, or to actually handle large forces.
(on my boat, ~40 ft, I deliberately let the aft stay rest on the stern rail in order to easier open the aft lockers ... I have no problems with this. None. ).

You are upset that the rigger has set your rig with high tension. I would not do that myself, as I am lazy - prefer to go on the soft side. But there is nothing wrong with doing so, even if it exceeds all strange recommendations.

There has been some interesting argumentation in this thread. Some of this is clearly home brewed thinking. Personally I mostly agree with Rick H who correctly identifies that all materials will have be elastic (to some degree) and thus works as a spring. the mast and rig acts as a system of springs, so does the hull (+ deck etc) and it is this combination that should tuned to something that works in the wind range targeted.

Some further comments:
1) even if you may be far from the breaking tension, the material (wire, whatever) may very well be deformed. Generally speaking, one should keep tension well below breaking point in order to avoid deformation, for wires - elongation.
2) High rig tension may damage the hull and expose the chainplates fastening for higher stress than really intended (rather common issue on older boats).
3) a wire is a spring in more than one way, firstly as the material in itself is somewhat flexible and secondly as the wire consists of thinner threads spunned around eachother, just like a traditional rope or a ... spring!
4) Have you ever thought about what happens when you tighten the back stay in a blow? The top of the mast is moved back and down, thus the side stays will be less tight, the mast will lean to the lee side - a way to spill wind which is good in the blow.
But, again, that means that some of the tension you put in the side stay is lost.
This is a good though example demonstrating that it is worthless to speculate on static settings. Rig shall be set during sail, alternatively the rigger should know what he is doing.

/J
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post #40 of 42 Old 08-09-2015 Thread Starter
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Re: Rig tension too tight?

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This is not as serious as you (and others) may think.
Surprisingly low force is needed to move a string some little distances. Think about a guitar string, tensioned as it is, it is still easy to move it.
It really looks as the backstay should not touch the stern rail. So, yes it was not really correct mounted. But this doesn't make the stern rail to be a part of the rig, or to actually handle large forces.
(on my boat, ~40 ft, I deliberately let the aft stay rest on the stern rail in order to easier open the aft lockers ... I have no problems with this. None. )./J
Wonder how your stern rail feels about it?

In my case, there was enough pressure on the stern rail to substantially deflect the chainplate. That's a lot of pressure, and for a rigger to rig that it way (especially when there was clearly a better option) is nothing short of negligent IMO.

Quote:
You are upset that the rigger has set your rig with high tension. I would not do that myself, as I am lazy - prefer to go on the soft side. But there is nothing wrong with doing so, even if it exceeds all strange recommendations.
Several articles I've read state that a loose rig is worse (for the rig) than a tight rig. In fact, loose rigs are often cited as the most common rigging mistake. However, obviously, there are limits to how tight a rig should be. That is my concern.

Quote:
This is a good though example demonstrating that it is worthless to speculate on static settings. Rig shall be set during sail, alternatively the rigger should know what he is doing. /J
Yeah...and 3 pilots "should" have been able to get that Asiana plane safely on the runway at SFO. Unfortunately, my faith in "experts" diminishes more by the year!

Dedekam says: " Many yachtsmen intuitively tension their standing rigging and adjust it later when sailing. This may lead to acceptable results, but the methods described above" (measure and stretch), "while taking some time, are more reliable.". He then goes on to describe fine tuning while sailing.
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