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tolman_paul
Trad climber
Anchorage, AK
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Apr 15, 2009 - 05:48pm PT
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No rope or roped system is full proof. Which is why that old dictate about the leader not falling is a good one to follow.
Single ropes have their place. They are the simplest and lightest way to belay. The down side is on wandering pitches they present additional rope drag, if you fall while clipping you face a longer fall then if you clip one rope at a time with a dual rope system, and they have no backup should they be cut over an edge. Oh, and should you need to do full pitch rappels, you need a means of pulling the rope.
Two rope systems have their place, and pitfalls as well attested in this thread.
I use both single and 1/2 ropes. They have their place. For the majority of the climbing I've done, a single rope has had more plusses than minuses. On routes with the potential or requirement for full length raps I've done them both with 1/2 ropes and with a single and a 1/2 rope as the pull line.
If you need to carry two ropes, give strong consideration to the second rope being capable of more than just retrieving your main line. Using a 10, or 9 something single and a 1/2 rope of whatever diameter as the pull/backup line makes alot more sense than a single and an overweight shoestring. The 1/2 rope isn't that much heavier than a static 7 or 8, but it is 10 times more useful should something happen to your main line.
I can understand why bachar solos, start at the bottom, don't fall, walk off the top. Pretty simple system.
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August West
Trad climber
Where the wind blows strange
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Apr 15, 2009 - 06:33pm PT
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"When climbing in blocks, August— plan on swapping rope-ends, so you don't have to touch the you-know-what! It's a pretty quick way to go, if it's part of your routine. I don't know that it's not conventional— you're probably using a daisy anyway at change-overs."
For a single rope, we have gotten to the point where we can flake the rope on a sling and "flip" (or "roll" might be a better term) the rope over quickly without problems. Since I have had problems flaking double ropes over a sling, I wouldn't try this with doubles.
In the past, I have swapped rope-ends for leading in blocks (both untieing-re-tieing and, alternatively, tieing a double 8 on a bite and clipping a locking biner between harness and rope). But doubles are slower. And it brings up another issue with doubles: when the leader starts out, both strands appear to be parallel and separate. However, by the time the second gets up to the anchor, you find that the strands are twisted over each other (and this helps add kinks to the ropes). One would think that untieing and carefully re-tieing would solve this problem (at least for the next pitch), but it never quite seems to work out that way. (And yes, starting off the ground, I pull both ropes, all 60m, all the way through my atc device, to make sure they are parallel, before tieing in.)
I'm pretty happy with my 70m single or, occasionally, leading on a 60m and tagging a 8.8mm for rap line/emergency lead line. So I'm not very seriously considering going back to doubles. But every time somebody sings the praises of doubles (especially to climbers who haven't used them), I'm always like, "wait a minute..." And I am curious about those that have stuck with them long term (since most who try them seem to be like me in that they eventually go back to singles).
But each to their own. Not trying to talk anybody out of them, just wondering how some climbers claim to be happy with them...
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 15, 2009 - 07:42pm PT
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Im just a big chicken. Doubbles are more work but they offer more security.
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Mar'
Trad climber
Fanta Se
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Apr 16, 2009 - 02:38am PT
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Yeah— and it's a bad habit too! I've also been a 30 year addict of the 1-1/2 fisherman's bend to tie-in. Small, fast, neat and easy to get in and out of. I have a funny way of dealing with crossed lines— I do pirouettes as needed as soon as I start off— sometimes it works, sometimes it doesn't. It's just part of romancing the stone.
Whether you prefer doubles or not, it's best to have mastery of any technique that suites the occasion, regardless of general preferences. It really depends on your objective. I'm happy to use my single whenever it's appropriate, but my "desert island" rope would be a double.
I know people like Werner (including me), who've been leading on single-strand 1/2 ropes since the mid 80s. When you have no doubts, there is no right or wrong, no better or worse way.
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Osmo
Trad climber
Calgary, Alberta
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Apr 16, 2009 - 06:32pm PT
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To tradmanclimbs re Apr. 12 1:48 and 2:55pm: sorry, I haven't seen what Sterling Ropes have to say, but THEY HAVE IT WRONG IF they say what you say they do, as they can't change basic physics. Given a specific fall situation, what happens is that the climber has a fixed amount of ENERGY when he hits the rope--whether he falls on a thin rope or a thick rope, each rope absorbs all that energy if it stops the fall: if it's a thin rope, it has a low K-factor (spring constant) and will stretch farther to absorb that energy--the impact (or peak) force occurs at his lowest point and the energy is the area under the rope-tension vs. stretch-length curve; but if it's a thick rope, it has a higher K-factor and will not need to stretch as far to absorb the same energy of the falling climber, because the rope tensions are higher at each stretch length. Again the impact force is the tension in the rope where the climber stops falling, and will definitely be higher in the thick rope than in the thin rope (same materials, etc. of course) because the forces must be higher since the distance is shorter; the common belief is common because it's correct. It's the same principle as used in all 'cushioning' materials, like crash pads: reduce the impact force by increasing the impact distance, by using a soft material, for example a thin (stretchy) rope. Osmo.
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tolman_paul
Trad climber
Anchorage, AK
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Apr 16, 2009 - 06:37pm PT
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It's not quite as simple as saying the rope is a spring. Some of the energy is converted to heat, from the rope fibers running over themselves internal to the rope, and the rope funning across biners, rock etc.
The little ropes break after fewer falls (when used as singles) because there is less rope to take the heat, and more heat damage per fall.
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 16, 2009 - 07:56pm PT
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Osmo, jim from sterling did the drop tests on 1/2 ropes with the full 80kg weight and the numbers are right arround what you would expect for a single rope. That is for the 1st drop only. I understand that the numbers go up dramaticly after the 1st drop but jim did not post that info. Those super low impact forces that they advertise for 1/2 ropes are all done with a 55kg weight.
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Osmo
Trad climber
Calgary, Alberta
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Apr 16, 2009 - 09:46pm PT
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One thing I didn't say before, because I was already going long, is that most falls are fairly low fall-factor, relatively dynamic, and so, in the elastic range of ropes, even small ones; and so that's what I was talking about. Someone else already said that ropes in the real world live a lot longer than the tests suggest, because the fall situation in real climbing tends to be much gentler than the tests, which are statically belayed and very severe.
Obviously the UIAA tests ropes to failure, and that means that their tests push ropes beyond the elastic, into the plastic range, where permanent deformation (stretch) and stiffening happen; in effect the rope becomes a caving rope. After the first drop, there's less stretchiness to absorb the fall energy, and so the peak (impact) forces leap up, and so does the per-drop damage to the rope (and anything connected to it).
The good thing about standard tests is that they are consistent and repeatable, but in order for them to be of any use, they MUST have an end; in other words they must push the rope to destruction, in a standard way, to tell the world exactly what the rope can take. Unfortunately, too many climbers interpret the "falls held" literally, in terms of their real world of climbing, and are ready to retire their good rope after a couple of modest falls, while the rope might readily handle 100 falls of that type.
The UIAA want everyone to be safe, while rope makers want to sell rope, so they would like climbers to presume that every fall is a worst-case fall and buy a new rope around the occurrence of the prescribed number of official falls (to be safe, you know...).
Meanwhile, climbers who don't want to be getting new ropes for every trip, need only keep aware of the kinds of falls they've been taking, and be realistic about what the official drop test results mean to them. A start would be for the new ropes to be labeled, "DROPS held" to keep buyers aware that "drops" does not, generally, mean "falls", by a huge margin.
Osmo
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 16, 2009 - 10:37pm PT
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Dude, what does all that drivel have to do with the simple fact that 1/2 ropes contrary to populer myth DO NOT HAVE SOFTER IMPACT FORCES THAN SINGLE ROPES?
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Osmo
Trad climber
Calgary, Alberta
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Apr 16, 2009 - 11:41pm PT
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That's the point: they DO, as I see any number of guys on this forum have experienced. A THIN ROPE GIVES A SOFTER CATCH--this means a lower impact force than a thick rope, unless maybe it's a real bad (unusual) fall: high factor, big climber, and a very thin rope, so it gets pushed into the plastic range, where the force shoots up (a bit).
What made me post in the first place is that suddenly I see a bunch of innocent climbers being told to change their understanding (which is readily demonstrated: ie., true) that a thin rope gives a softer fall-stop--easier on the climber and easier on the pro., NOT easier on the rope of course, because it gets stretched more than a thick rope. And all on the basis of generally unrealistic test results, which almost never apply in a climbing situation.
Osmo
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 17, 2009 - 12:00am PT
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Osmo, yer smokin that shite again. The numbers don't lie. if you fall on a single strand of skinny 1/2 rope your fall will be just as hard or harder than the same fall on a standard single rated rope.
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 17, 2009 - 09:49am PT
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This is one of the biggests myths surrounding the aura of the doubble rope system. The mear act of clipping a skinny rope to a suspect piece of gear does NOT magicly give you a green light. You can however use your doubble ropes to share the load over several pieces of suspect gear thus reduceing the load that each piece feels.
It has however been my experience that most double rope falls end up being caught by a single piece of gear clipped to a single strand of rope.
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Osmo
Trad climber
Calgary, Alberta
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Apr 17, 2009 - 04:20pm PT
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Sorry Tradman; I thought you'd be interested in doing some good for the climbing community--that's what we should all be doing here, and it's what I'm trying to do; I also take it that you're a very experienced climber, so you should know the difference in shock loads of thin and thick ropes from feeling them yourself.
What I'm saying is, "Hold on, everyone--don't go off on a tangent, changing what you always 'knew' to be true because of some numbers that don't really apply to CLIMBING". They are numbers from tests designed to break ropes, and I haven't even seen the numbers you're talking about.
You would like us to believe that all a climber needs to do to soften a fall is lead on two ropes of a certain size instead of one?--no doubt a bundle of the same ropes would give a VERY soft fall. Everyone will see that this just doesn't make sense--you'd hit the end of the rope and stop dead, likely pull the pro, tear out the anchor, or tear out of your harness. Just consider bungee jumping: they use a very stretchy 'rope' exactly to minimize the impact force by absorbing the fall energy in the stretch distance.
I'm sorry to disagree with you, but I think what you're saying even goes against what even YOU have known until now, but you saw some test results and misinterpreted them as a new revelation that goes against what climbers have known for years, not only from physics, but from experience in thousands of falls.
Just trying to be constructive: the UIAA test system results do NOT apply to the vast majority of real-world climbing falls, as long as we don't go overboard at thinning down our ropes, and so pushing them to, or near, their breaking point.
Osmo
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Brian Hench
Trad climber
Laguna Beach, CA
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Apr 17, 2009 - 05:48pm PT
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Does the equation used to calculate Impact Force correct for the fact that single ropes are drop tested using a 80 kg weight and half ropes are tested using a 55 kg weight? Can you directly compare the Impact Force rating that comes with the rope and say that the one with the lower impact force gives the softer ride?
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 17, 2009 - 09:46pm PT
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Brian look up thread and follow the link to jim ewings post. For as long as i have known about doubble ropes (since about 1985) we allways assumed that they had a softer impact force on the gear than single ropes. This was a combination of old wives tales (see Osmos posts) and the fact that the 1/2 ropes are tested with a lighter weight 55kg than the 80kg weight used for single ropes. That 55kg test gave some really light published force numbers.
Jim from sterling rope went ahead and tested some 1/2 ropes with the 80kg weight and big supprise to most of us he proved that the 1/2 ropes are not nearly as soft as we thought they were. This is important info for anyone who uses the doubble system for funky gear placements. You can't just clip a skinny rope to a crap piece thinking that your rope is extra soft and call it good. Your rope is not extra soft and will yank that crap gear just as fast as your old fat single rope. If the gear is crap you still should use screamers and multiple pieces clipped to seperate ropes unless you like to ignore facts and bury your head in the sand.
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 17, 2009 - 09:52pm PT
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Osmos, I feel the UIAA tests and breaking stuff is very helpfull. You have to know how to apply the results to climbing scenario. In this case it is clear to me that the information Jim posted would change the way I use and think about the doubble rope system.
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ionlyski
Trad climber
Kalispell, Montana
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Apr 20, 2009 - 01:26am PT
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Is there any advantage to building your protection "system" all on one rope? Multi directional pieces early in the pitch, protecting nuts and cams farther up the line from zipper effect and other nasties and so maybe losing some of that security because there are fewer pieces per rope in the double rope system?
That sounded moronic didn't it? Yes, it did.
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Osmo
Trad climber
Calgary, Alberta
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Apr 20, 2009 - 01:54am PT
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Hi Tradman; We're still waiting for the "facts" that you're talking about. In fact, the UIAA rope test results are almost completely useless to climbers, and I only say "almost" by habit, to allow for the slight possibility that someone might come up with some vague connection between those tests and climbing.
Convincing climbers to use a thick rope instead of a thin one, or clip in both ropes instead of just one, on manky protection, becomes a matter of dangerous misinformation if you're wrong.
The impact forces stated from the UIAA-type tests do not relate to climbing, unless you are habitually taking FF1.7+ falls on a completely static belay, through a rigid piece of protection. ARE you? Have you EVER taken one? Do you know anyone, or even ever heard of anyone, who does? Right: No, and you don't. And you also don't know anyone (including you and me) who knows how to "apply those results to the climbing scenario", because they don't apply, at all, in at least, say, 98% of climbing falls.
Why that's important is that the UIAA test setup is not just a severe extrapolation of a real climbing fall situation: the test pulls the rope right out of the elastic range and into the plastic (ie., destruction) range, where it behaves as a very different material and exhibits the distorted impact forces that you mentioned. The normal climbing protection system is intended to keep the rope in the elastic range: big enough rope, small enough climber, low-enough fall factor. As long as this is done, a rope is good for a huge number of falls, and thin ropes stretch more and produce lower impact forces than thick ropes, as has long been known by countless climbers (as well as the physicists).
Here are a 'coupple' of comments which I've borrowed verbatim from Climbing.com, on the UIAA rope tests:
"Falls held. The UIAA standard fall test is thankfully very severe, far outstripping almost any fall you might encounter in the real world.
Static and dynamic elongation. Dynamic elongation is measured on the first fall of the standard UIAA fall test. The higher the dynamic elongation percentage, the cushier your fall."
There you have it, and everyone knows that a thin rope elongates more during a fall (ie., dynamically) than a thick rope. But don't take my word for it.
By the way, Sterling Jim is obviously doing the right thing by testing every lead "rope" with 80kg, incl. half-ropes being used individually for leading. But again those tests tell climbers almost nothing (and all the numbers are irrelevant) except that the rope can withstand extreme abuse well beyond regular climbing falls. Keep in touch.
Osmo
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tradmanclimbs
Ice climber
Pomfert VT
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Apr 20, 2009 - 09:25am PT
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cosmo osmo. Reading comprehenson skills. Jim had proven that single and half ropes have simeler impact numbers when tested with the same weight. That fairly clearly dbunks the old wifes tale that a skinny rope when used by itself is softer. Add to this the known fact that as ropes wear out their impact forces get higher it shouldn't take rocket science to figuer out that it is a good idea to use multiple pieces in situations where the gear is funky and the chances of a fall are high. With the Double rope system you can spread the working load over both ropes seperatly and therfore improve your chances of survival.
Your argument seems to be that skinny rope has such a soft impact force (old wifes tale) that you can stuff that Grey #00TCU behind an expanding flake and simply because you have your magic skinny rope you can just clip it and go. No need to worry about adding a screamer or backing it up with a piece clipped to the other rope. Heck eveyone knows these skinny doubbles are soft so i'm gonna just clip this one crap piece and go fer it dude....
By all means PLEASE DO because this is geting old and I actually have work to do today....
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ionlyski
Trad climber
Kalispell, Montana
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Apr 20, 2009 - 12:20pm PT
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It's only getting old because you guys are arguing instead of discussing. This is exactly the type of thread that should be continued to be discussed. If there is anything to learn here, I'll keep checking in for any little, new tidbit. It beats the off topic threads.
Cmon guys. You gonna ignore my post above? Is there an advantage to sewing up a pitch on one rope, in regards to preventing zipper or walking cams?
Arne
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