Shelf Life For a Rigging Line

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Did the rope have 'blue' in the center of each strand?...

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I got right on the case when I read this--maybe we could actually identify the rope! It certainly was one of the very early dacron ropes. When I called the previous owner and abuser of the rope just now, he could not remember any blue strand, and I don't remember seeing one when I broke it. He is pretty sure he remembers a published strength of 6200 or 6400 lbs.; this would mean the residual strength is about 60%.

There is a small back story to this affair. I had been after my friend to replace his ridicuous ropes for some time, and even after I had prevailed on him to buy some modern arborist ropes, I would occasionally catch him tying into one of his miserable old ropes for no good reason at all. When I finally got the small piece for testing, I was sure I would be able to show him the grave danger he was running every time he tied into the dirty fragile wreck of a life line. Unfortunately, the numbers didn't quite convey that message to him.
 
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Did the rope have 'blue' in the center of each strand?...

[/ QUOTE ]
I got right on the case when I read this--maybe we could actually identify the rope! It certainly was one of the very early dacron ropes. When I called the previous owner and abuser of the rope just now, he could not remember any blue strand, and I don't remember seeing one when I broke it. He is pretty sure he remembers a published strength of 6200 or 6400 lbs.; this would mean the residual strength is about 60%.

There is a small back story to this affair. I had been after my friend to replace his ridicuous ropes for some time, and even after I had prevailed on him to buy some modern arborist ropes, I would occasionally catch him tying into one of his miserable old ropes for no good reason at all. When I finally got the small piece for testing, I was sure I would be able to show him the grave danger he was running every time he tied into the dirty fragile wreck of a life line. Unfortunately, the numbers didn't quite convey that message to him.

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Awesome! Thanks for the quick response.
If it was truly 35 years ago (1975ish), there weren't too many dacron ropes out there, at least that were available in the Chicagoland area. I remember the 1st one we got had an ABS of 4,400 lbs, and it was right about that time. It looked very similar to the one in the pic. Maybe there was somethin else available in the Northeast?
Thanks again.
 
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I'm on our campus technical rescue team (confined space, but remarkable overlap to tree climbing), and we're replacing a couple of unused ropes at (i think) 10 years, per manufacturers instructions. I agree with someone above, to ask the maker, so you don't have to ask the big one.

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What happens to the replaced ropes?
Can we get them to be tested, perhaps?

*kN*
 
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Yosemite SAR tested several unused 10 year old dacron and nylon ropes and found they retained almost 100% static strength but almost all broke on the first test fall.

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This stands in stark contrast to a the UIAA report (ca. 2000) in which it was asserted that "all ropes --even 25 years old-- held at least one fall" (something to that effect). And these ropes weren't merely old, but old and used, IIRC. It was said that for top-roping (sling-shot belay, rope up through anchor and down to climber), it should be safe to use a rope until its sheath wore through.

The Yale statement quoted elsewhere sounds like not only CYA but GMS (generate more sales)! Yes, usage plays a role. I think that it is Beal, perhaps, who have come out with a 10-year recommendation, which stands as longer than the old 2-to-4 and at least by 5-years recommendations climbing rope makers used to toss around.

But just feeling confident and using ropes w/o trouble (SO FAR) isn't great evidence for their longevity, either. IIRC, Lazarus did some testing of used ropes and was rather surprised at how much strength >>some<< of them (Brand X but not others, e.g.) had lost.

So, here's to hoping some testing can be done on retired ropes, rather than making rugs or other mundane uses that give no information.

*kN*
 
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