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sspssp
Nov 5, 2007, 9:30 PM
Post #26 of 38
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chossmonkey wrote: sspssp wrote: Factor 2 falls (even if using singles as twins) is not instant death. Common guys, get real. True, on multi pitch (unless you knot the ropes) high factor falls your falling buddy will just give you rope burn until you let go of the rope and drop him to the end of the rope.
I understand that climbers get warned alot about avoiding F2 falls, with good reason. But this is the sort of stuff that makes me roll my eyes. If you can't catch a F2 fall, you shouldn't (in my humble opinion) be belaying.
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sspssp
Nov 5, 2007, 9:36 PM
Post #27 of 38
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jt512 wrote: sspssp wrote: vegastradguy wrote: if you're belaying on both lines and the leader happens to fall before they get the first piece clipped, you're looking at a factor 2 with a pair of 10.2 ropes. not good. ... can you use 10.2mm lines as doubles- sure. however, it is absolutely imperative that the leader DOES NOT FALL before getting one of the ropes clipped on lead. the resulting forces could be deadly. Factor 2 falls (even if using singles as twins) is not instant death. Common guys, get real. I've had partners take factor 2 falls on a daisy chain (aid falls) and it can leave bruises but it is not the end of the world (I also took a 6~8 fall where I came to a static stop when my fifi hook hooked a piece on the way down). Singles as twins sounds really bulky and heavy and it will up the impact forces. You will get shorter falls (less stretch), good for blocky climbs where you could hit a ledge, and higher forces on gear, bad if the pro is sketchy or the rock quality is iffy. I've been reading your posts for years, and usually you don't post anything blatantly stupid. This post, though, is an exception. Jay
Ok, if I hadn't been rolling my eyes so much, I might have worded this a bit better. I think using singles as twins (unless they are rated for it like the Joker) is a pretty stupid idea. But particularly with the thinner, generally stretchier, singles that are out there now, the impact forces just aren't going to be sudden death (is this where I am being blatantly stupid?). I would imagine that the single 11 mm ropes that were in use 20 years ago probably (too lazy to try and research it) had higher impact forcers than using 2 of the newer "low impact" singles do today.
As an aside, I guess some of it also is that I'm a little frustrated that things like factor 2 falls and low impact forces so dominate all discussions of rope safety when talking about lead falls. For the high quaility granite that I typically climb, I would like to have more options (when it comes to choosing ropes) for shorter falls (less stretchy ropes) even if that means a tradeoff for higher impact forces.
cheers
(This post was edited by sspssp on Nov 5, 2007, 9:40 PM)
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tradmanclimbs
Nov 5, 2007, 10:09 PM
Post #28 of 38
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Contrary to most internet mythology fatter ropes often have less stretch and lower impact forces than skinny ropes. It depends on the rope. RTFM
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cchildre
Nov 5, 2007, 10:25 PM
Post #29 of 38
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Only thing to add-
How much does a new rope cost?
How much would you pay to escape death or sever injury?
Questions that my old mentor would always ask me when I start talking about saving cash on gear, or shaving cost by working with gear that should be retired.
Not sure if that was the point of this discussion, or fully relates. Just my 2 cents.
Good thread to read.
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andypro
Nov 5, 2007, 10:39 PM
Post #30 of 38
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Registered: Aug 23, 2003
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What's the point in buying two singles over two doubles?
If you're going to use a single you've already got...even if you buy a matching new rope, it's characteristics are not going to be the same as the one you've already got. Ropes age...hence we retire them.
I don't think that rope companies are rating ropes for performance and purpose as a marketing ploy. If it's rated as a single, use it as a single. If it's rated as a double, use it as a double. If it's not rated as a twin, I wouldn't use it as either.
I have, however, used a double as a single for short sections. I don't see anything wrong with that, just don't use it as your primary single.
All of this seems kinda ridiculous. Would you use an axe to cut bread? Would you use a bread knife to cut up your firewood? Sure, they'll both work for each others purposes, but it's hardly an optimal situation.
--Andy P
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vegastradguy
Nov 5, 2007, 11:09 PM
Post #31 of 38
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sspssp wrote: I think using singles as twins (unless they are rated for it like the Joker) is a pretty stupid idea.
ah, but the danger in using singles as doubles only appears when they, in reality, are functioning as twins- that is, immediately off belay with no pro in yet.
In reply to: But particularly with the thinner, generally stretchier, singles that are out there now, the impact forces just aren't going to be sudden death (is this where I am being blatantly stupid?).
i certainly didnt proclaim instant death should this scenario occur, but it actually is a distinct possibility. despite lower impact forces of todays ropes, the OP is talking about a pair of 10.2mm lines. Depending on the manufacturer, that means impact forces of up to 9+ kn PER rope....
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chossmonkey
Nov 6, 2007, 12:26 AM
Post #32 of 38
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For what it's worth, the maximum impact force is 12 kN for single ropes. Many singles are 8.4 to 10.
The potential for 16- 20kN is way more than I care to deal with.
Don't forget, if they redirect through the anchor you can approximately double the force again that the anchor could see.
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stymingersfink
Nov 7, 2007, 2:01 AM
Post #33 of 38
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chossmonkey wrote: For what it's worth, the maximum impact force is 12 kN for single ropes. Many singles are 8.4 to 10. The potential for 16- 20kN is way more than I care to deal with. Don't forget, if they redirect through the anchor you can approximately double the force again that the anchor could see.
I'm curious what his input will be.
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dfrancom
Nov 16, 2007, 9:30 PM
Post #34 of 38
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Registered: Mar 15, 2004
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How about two 8.3 mil dynamic ropes.. does a fall on these ropes creat more force than one 10.3 and should you always only clip them seperatly on pieces, or can you do them together?
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climbhigher
Nov 18, 2007, 1:28 AM
Post #36 of 38
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Registered: Dec 6, 2002
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I am a small climber.....Pushing 145lbs. But, I know when using double or twin rope technique, you are more weighed down with those ropes with rope drag passing through your gear, as oppose to having one free rope on the back of your harness and leading with another rope. Being a heavy climber you don't have to worry so much of the diameter of the rope. Just the working elongation of the rope. This should measure around the low 30% area. And the static elongation if you do alot of top roping. In reply to: Cheers, Chris.
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andypro
Nov 18, 2007, 2:18 AM
Post #37 of 38
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stymingersfink wrote: How difficult is the whole concept of half & twin ropes to understand? 
For that matter, how difficult is the whole concept of single vs. half vs. twin?
climbhigher wrote: I But, I know when using double or twin rope technique, you are more weighed down with those ropes with rope drag passing through your gear, as oppose to having one free rope on the back of your harness and leading with another rope.
I think you have a misunderstanding of the point of double ropes. The reason to use them is to avoid the drag that a single rope would impart on the system on a wandering/confangled route. As far as weight goes, two single ropes are going to weigh more than two half ropes, no matter where you're hanging the second rope from.
--Andy P
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tkambitsch
Nov 18, 2007, 6:00 PM
Post #38 of 38
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Registered: May 13, 2002
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andypro wrote: I think you have a misunderstanding of the point of double ropes. The reason to use them is to avoid the drag that a single rope would impart on the system on a wandering/confangled route. As far as weight goes, two single ropes are going to weigh more than two half ropes, no matter where you're hanging the second rope from. --Andy P
Andy, you hit on the reason for my original post. I was pondering ways to lighten the load for me and my partner (combined weight of 435 lbs.). We used to climb multi-pitch routes with me leading on a 10.5 single and then dragging another single. Recently my partner has been carrying a 10.2 in a pack, making it easier for the leader but a pain for the second. We are looking to replace the older, thicker rope.
The earlier replies to my query quickly answered my question. I won't be playing around with twin or double rope technique on two single rated ropes. But we'll probably not buy twins or doubles either. We are looking to buy a pretty thin single (9.4 or 9.1) and pack or drag it up and use it primariy as a rap line with the luxury of having a single rated rope available in case of a stuck rope or an emergency.
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