Jim;
Yes, I agree. Any rope should probably be replaced after a number of
full-stress cycles.
BTW, ever tried vertical caving? It's a lot like conventional climbing
except for the mud, the wet, and the dark!
Regards, Neil Tucson, AZ
-----Original Message-----
From: Waldron, James [mailto:James.Waldron@CWUSA.COM]
Sent: Monday, October 28, 2002 9:34 AM
To: land-speed@autox.team.net
Subject: RE: Parachute Deployment Load Rates...
...Snip
>...If the rope is Manila, like in the "olden days", the climber's body is
>brought to a sudden stop, generating tremendous "G" loads.....
>
>...The development of nylon rope changed the whole character of climbing &
>caving. Nylon stretches as it is pulled taut. This spreads out the time
over
>which the body is brought to a stop, greatly lowering the "G" forces on the
>body and, consequently, the peak tensile load on the rope....
>
>...Special climbing- grade
>nylon rope has been developed to feature an excellent combination of
tensile
>strength, elongation, and energy absorption. These ropes absorb energy as
>they stretch, minimizing injury to the climber and this also reduces
>rebound......
As one of those crazy rock climbing guys I though I should also add to this
that the climbing rope I use is 'certified' for only 12 falls!
(different ropes have different numbers, max is around 14, I think.)
After that the rope is retired (I cut mine up for utility tie-down use).
I keep a special log that records how many falls on each rope.
UV can be a problem (ropes are stored in the dark) and dirt, abrasion,
knots, sharp bends, and sharp rock corners, tend to make one very
conservative
as a rope approaches it's rated limit.
Bottom line is that this kind of rope used as a parachute tether would have
to be replaced after X number of deployments.
Thanks,
Jim.
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