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Old 04-13-2010, 01:45 AM
Robbie.g Robbie.g is offline
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Join Date: Feb 2008
Location: Bay of Islands, NZ
Posts: 89
Default Wobbly wire.....

So SS1x19 holds up a rig....has a finite strength....finite amount of elasticity.
My understanding is that the wire stretches and recovers as the load comes on and off, and when the load hits maximum elongation the wire does not recover fully!?!. (i belive it's called plastic deformation).
After after such an event the wire could no longer be uniform,when you run your hand up and down the wire it is not straight, and smooth ; but 'wobbly'. i'm not talking about strands lifted but the whole length of wire has 'wobbled'.
Should i use the 'wobbly wire' feel,as an indicator of possible overloading of the wire (either by being under spec.ed or suffering from some event that the wire/rig was not designed ).
This all seems straight forward enough in my head, but some other opinions have put in the seeds of doubt.
What do ya think?
Thanks
Robbie.g
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  #2  
Old 04-14-2010, 06:54 AM
Brion Toss Brion Toss is offline
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Join Date: Jun 2005
Posts: 1,180
Default Options?

Hi,
No options here, at least if you want anything like an optimal rig. The wobble might have been there since the wire was new, the result of poor drawing and layup, in which case it isn't optimal. The wobble might be the result of yarns breaking inside the terminal, as a result of corrosion/fatigue/poor termination/whatever. Also not optimal. It doesn't seem likely that exceeding the elastic limit would produce a wobble, but hey, if there's even a remote chance that this might have happened, I don't think we're talking optimal. In short, I can't think of an explanation that won't lead a rational person to want to get that wire off the rig as fast as possible.
Just curious, though, what other opinions have you suffered on this topic?
Fair leads,
Brion Toss
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  #3  
Old 04-15-2010, 12:37 AM
Robbie.g Robbie.g is offline
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Join Date: Feb 2008
Location: Bay of Islands, NZ
Posts: 89
Default opinions....

my theory has just been brushed off with a 'it's how it is' and 'i'm not worried' ,as the mast & rig are quite young and has done only a few miles and there was no other visual signs on the stays etc. These views were from respected sources.. As it turns out the wire (which is a cap on a cat) is undersized based on the rig plan we've got hold of from the owner; 10mm in place of 11mm [difference of 1520kg's in breaking load]. which i didn't know at the time of the check. so i could feel exonerated. still, i think that the 'wobbly wire' could be an indicator of something going on that's not quite right. As you say, possibly inside the fitting. Maybe I'll keep the wobbly wire thing as a flag to think a little more about the 'suitability for the role [loads]'. If the wire don't look/feel right, then how does the rest of the rig stand up.
Optimal ; good word. should get more use,.......the thing is not knackered it's not optimal.
Thanks Brion
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