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Dirty rope vs. clean rope
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majid_sabet


Jan 31, 2011, 1:11 PM
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Dirty rope vs. clean rope
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The old adage “the person who steps on the rope buys beer” took on new meaning at the 2010 International Technical Rescue Symposium (ITRS) this November. We all accept that dirt reduces a rope’s strength. Presumably, grit inside a rope cuts and abrades the fibers as the rope stretches and relaxes during use. But to what degree is a dirty rope weakened? Our study presented at the ITRS examined just that, and the findings should make climbers re-examine their gear. Although the study was done with an eye toward vertical rescue, its findings are readily applicable to normal climbing. Prusik-style lengths of 8mm cord were soaked in dirty, gritty water, allowed to dry, and then put through five, 1,000-pound slow pulls to mimic realistic cord usage during rescue operations. The study found that after one soiling/pulling event, the cord had lost approximately 20 percent of its strength. After eight cycles, it lost 40 percent of its strength.

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http://www.climbing.com/...irty_little_secrets/


USnavy


Jan 31, 2011, 2:52 PM
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Re: [majid_sabet] Dirty rope vs. clean rope [In reply to]
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Great article, if only the people who died because of dirty ropes would have read this... Oh, wait there weren’t any...


jeepnphreak


Jan 31, 2011, 3:35 PM
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Re: [majid_sabet] Dirty rope vs. clean rope [In reply to]
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Im going to go wash my ropes and cords right now.

Wow 40%... Unsure


Adk


Jan 31, 2011, 6:03 PM
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Re: [majid_sabet] Dirty rope vs. clean rope [In reply to]
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That must mean that most of us climb on ropes that are way beefier than we need or that rope manufacturerers make ropes beefy because they know they are going to get dirty and we are going to fall on them anyway.Crazy


Interesting yet how many of us have climbed and fallen repeatedly on dirty ropes?
Thank god , or whomever, that none of us are anal about an occasional "Hey man, you stepped on my rope"?
Now you buy beers while I'd probably be thinking, I'll rather spank your girl instead!


rescueman


Jul 5, 2011, 1:32 PM
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Re: [jeepnphreak] Dirty rope vs. clean rope [In reply to]
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jeepnphreak wrote:
Im going to go wash my ropes and cords right now.

Wow 40%... Unsure

Or lose 40% of your body weight ;-)


JimTitt


Jul 6, 2011, 11:36 AM
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Re: [majid_sabet] Dirty rope vs. clean rope [In reply to]
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All jolly interesting, the cavers did this one in the 60´s, the Germans in the 90´s and the Italians too. As has been noted above, until we have to climb over the piles of dead climbers to start a route I think we can leave this one in the `interesting´category. Realistically one has a better chance of dying from the lack of personal hygiene of the dirtbag jobbing in the local diner than ones rope.

Talking of interesting, have you noticed the logic flaws in the article?
If grit in the rope makes it weaker in a straight pull it doesn´t matter where the grit is, inside or out since the load and movement of the fibres is the same. Bent over a karabiner however the grit is better off nearer the neutral axis of the rope where there is least movement and load on the fibres, so further in is better. Wash away lads!
And when one lowers off a route the energy (and heat) are split between both the lower-off and the belay device which one could reasonably conclude is going to be the best scenario.

Is the rest of the paper the same?

Jim


rescueman


Jul 7, 2011, 7:43 AM
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Re: [JimTitt] Dirty rope vs. clean rope [In reply to]
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JimTitt wrote:
have you noticed the logic flaws in the article?

No flaw at all. It's the only way I get someone to buy me a beer ;-)


JimTitt


Jul 7, 2011, 8:32 AM
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At least it shows someone reads this stuff!


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