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| Messages 1 - 12 of total 12 in this topic |
jonnyrig
climber
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Topic Author's Original Post - May 31, 2016 - 12:28am PT
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Bought a brand spanking new Bluewater Canyonator 9mm x 200 ft (length is correct) static line, specifically to set a make-shift zip line across a creek on a camping trip.
Whether you think this is a good idea or not is immaterial at this point. The rope is rated to about 5,000 lbs, and it was tensioned in such a way as to have at least 10 degrees of sag, meaning the force generated on the rope by the rider would pretty much not exceed 3x their weight. The top end was anchored to a tree with a figure 9 and webbing. The lower end was rigged to a tree with 7mm cord and a 3-1 advantage employing a webbing klemheist to the main line and a releasable munter hitch on the pull side, in case the rig needed loosening to lower a stuck rider.
Question is, why would a Petzl Tandem pulley fuzz up the sheath? Is it just the mechanics of bending the rope at high speed? Do these static polyester lines have poor wear characteristics? Am I just pulling for a Darwin Award?
FYI, it was crossed about two dozen times. Heaviest rider probably tipped 300 lbs. The rope sheath fuzzed up far more than I would have thought for simply rolling through a pulley made for this type of thing. Anyone have any sort of valuable insight as to why?
Thanks.
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Studly
Trad climber
WA
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May 31, 2016 - 12:38am PT
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Did the rope not have a dry finish? That might do it.
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Killer K
Boulder climber
Sacramento, CA
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May 31, 2016 - 05:44am PT
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Sounds like the pulley was getting torqued sideways while riding. How we're you attached to the pulley?
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WBraun
climber
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May 31, 2016 - 08:02am PT
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Sounds like the pulley was getting torqued sideways while riding. How we're you attached to the pulley?
Yes, also is the pulley a bushing bearing or true ball bearing?
And how are you attached?
We've rigged zip lines where people grab a handle attached to the pulley and not clipped in where they shock loaded the line upon take off, lost grip, hit the deck, and got hurt bad (broken femur).
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jonnyrig
climber
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Topic Author's Reply - May 31, 2016 - 08:18am PT
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Bushing bearing. Attached by quickdraw, no handle and no opportunity to detach without really trying hard. Most dangerous aspect next to mainline failure would be a hand in front of the trolley.
Upon inspection of the trolley this morning, i see some grooves in one wheel, which appear as though its been used on steel cable. I think these are the cause of my sheath wear. Damn, wish i noticed them before trashing a new rope. Oh well, it was a blast and i got the rope cheap.
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WBraun
climber
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May 31, 2016 - 08:26am PT
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Try and use a high quality ball bearing pulley next time.
Bushing bearings are terrible for this application .......
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the Fet
climber
Tu-Tok-A-Nu-La
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May 31, 2016 - 09:07am PT
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Capt. Obvious here, but next time use a steel cable. Better, stronger, faster.
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Lurkingtard
climber
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May 31, 2016 - 11:22am PT
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Anyone have any sort of valuable insight as to why?
This is why.
FYI, it was crossed about two dozen times. Heaviest rider probably tipped 300 lbs.
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Moof
Big Wall climber
Orygun
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May 31, 2016 - 09:04pm PT
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When we rigged across the Patomac it was a 600' 7/16" line, and not tensioned that tight. The goal was more like a 20-30 degree bend, and you jugged back up to the other side after you stopped. Good CMI bearing pulleys too. Grand fun. The ropes were as new after, despite being a few years old. The caver owners knew how to treat them.
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| Messages 1 - 12 of total 12 in this topic |
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