|
mtn_eagle
Jan 4, 2005, 5:05 PM
Post #1 of 4
(791 views)
Shortcut
Registered: Jan 25, 2002
Posts: 88
|
Playing around with the force fall machine at www.alpinedave.com got me thinking about rope elongation. It's a number I never really spent much time pondering when I have bought ropes in the past. It's clear from the stats on the FFM that by increasing the elongation % that the fall force is considerably less. Since I weigh 190 lb and do a lot of ice climbing, this is very interesting to me.
My question is, besides the obvious longer fall, are there any disadvantages to buying a rope with longer elongation?
|
|
|
|
|
jpdreamer
Jan 4, 2005, 5:11 PM
Post #2 of 4
(791 views)
Shortcut
Registered: Dec 14, 2000
Posts: 232
|
I havn't tested it, but I would suspect greater wear and tear where the rope runs over the edge, especially if ascending as a fixed line.
|
|
|
|
|
vegastradguy
Jan 4, 2005, 5:41 PM
Post #3 of 4
(791 views)
Shortcut
Registered: Aug 28, 2002
Posts: 5919
|
i'm not entirely sure theres any other big reason to have a rope with high elongation. they are squishy though....rappelling is always fun with 'em.
of course, the biggest thing to look at is impact force. Beal is the best in this category, having the softest catching ropes out there, Bluewater also makes pretty soft catch lines as well.
check out this Web Page
|
|
|
|
|
chriss
Jan 4, 2005, 6:38 PM
Post #4 of 4
(791 views)
Shortcut
Registered: Jul 13, 2004
Posts: 92
|
Dave's fall calculator works pretty good, meaning mathmatically accrurate.
However, he states something about stretch being ~9% or something to that effect. Rope stretch varies with different factors in a fall (weight, fall-factor, etc). The UIAA rope test allows for up to 40% stretch in the test fall.
Use this higher percentage and Dave's calculator will be closer to the rope manufacturer's claims of impact force.
chris
|
|
|
|
|
|
