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Serious simul-climbing accident

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Postby phlipdascrip » Sun Jul 04, 2010 12:18 pm

brenta wrote:Initially, when the rope has just come taut and the tensions are low, static friction prevents the rope from moving across the biner and the climber with less rope is decelerated more violently. However, the tension in the rope on his/her side increases until the difference in tension between the two sides cannot be compensated by friction. Then the rope moves.

Right, didn't think of that. Would be great to have some simulation to see how everything actually plays together.
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Postby The Chief » Mon Jul 05, 2010 12:02 am

So Brenta, pre-determined spacing of Pro and rope slack between the two individuals when planned simul technique at "old skool" grades at or above 5.8 through 5.10 has no bearing on the rope tension/slack issue?

Of course Brenta and Fortmental, the two of you are elite experts at this simul- climbing gig even though neither you two have actually participated in it at grades at or above 5.8. And lets not even think about the rope diameter 8.9 -11mm (all having a completely different stretch characteristic of their own) or whether one uses a Single or Doubles, potential rope drag factor that may occurred as well that was not addressed. Factors of their own that totally and most assuredly insert a whole new mechanical twist on the rope slack and stretch issue.

But please, do carry on with your hypothetical science of this situ.
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Postby phlipdascrip » Mon Jul 05, 2010 2:36 am

I think it's interesting to get the theory straight first and then think about real life deviations and how they would affect the scenario.
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Postby The Chief » Mon Jul 05, 2010 6:00 am

95% or better chances that Reality will throw in variants that completely chuck the Theory deal right out the window.

The latest DMM Sling test results prove that and quite frankly, are very mind boggling. Another factor to be thrown into the equation that will end in totally different dynamic rope results between a standard 24" X 11/16" sewn runner, an 8mm x 24" Dyneema Sling or some different length Draws etc attached to the Pro etc.

Something else to remember, most slings and biners are rated a good 8-12 KN's greater than most Pro they are attached to. As the latest DMM tests show, the Dyneema Slings exert upwards of 22KNs of "static energy" before they blow. Thus, the Pro may indeed blow if one is directly attached to the Dyneema sling due to the force exerted on it from a simple 230cm fall directly onto the slackened Dyneema Sling. Read about the tests & Watchthe video and see for yourselves. Of course a dynamic rope will indeed incorporate a whole different set of factors. But, still a variable to be considered in this entire hypothetical equation.
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Postby brenta » Mon Jul 05, 2010 6:56 am

Let's start from the end...

The Chief wrote:But please, do carry on with your hypothetical science of this situ.

...and remove a bit of confusion. There are two sub-threads to this discussion.

1. Analysis of Tom and Bill's accident. This is what you focused on in your initial comment, saying that you would have rather soloed. I disagreed, and still do, but there was nothing that one would identify with science in that sub-thread. So, your exhortation to "carry on" must refer to the other sub-thread, namely,

2. Analysis of a second's fall that pulls the first off the rock. No one involved in the discussion so far has direct experience of that situation. The issue is whether anything meaningful may be said through reasoning. You obviously claim it cannot. Let's review your argument.

The Chief wrote:So Brenta, pre-determined spacing of Pro and rope slack between the two individuals when planned simul technique at "old skool" grades at or above 5.8 through 5.10 has no bearing on the rope tension/slack issue?

Spacing of pro, be it pre-determined or accidental, and rope slack obviously affect rope tension at all kinds of grades. Even my neighbors' dog would know it if they had one.

Note that Tom fell on a section of Redguard that is significantly easier than 5.8. We are talking about 5.4-5.5 depending on exact position and guidebook. On the other hand, once the falling second has pulled the first off a vertical face, does it matter whether it was 5.4 or 5.12?

How did you come up with the 5.8 threshold? You didn't read carefully or maybe it wasn't just curiosity that made you ask those questions...

The Chief wrote:Of course Brenta and Fortmental, the two of you are elite experts at this simul- climbing gig even though neither you two have actually participated in it at grades at or above 5.8.

In fact, here comes the textbook example of ad hominem. More predictable than a Swiss train and as logically flawed as these things get.

The question is: When the leader is pulled into the top biner by the falling follower, does (s)he stop right there, or does the rope start moving through the biner?

What is your argument? Do you have one? Are you suggesting that since you have no way to tell, nobody does?

The Chief wrote:And lets not even think about the rope diameter 8.9 -11mm (all having a completely different stretch characteristic of their own)

It is well documented that the "stretch characteristics" of ropes correlate much better with rope brand than with diameter.

The Chief wrote: or whether one uses a Single or Doubles,

...or one strand of half rope, for that matter.

The Chief wrote: potential rope drag factor that may occurred as well that was not addressed.

Your syntax is getting a little garbled here; hence, it's not entirely clear whether you are referring to Tom and Bill's specific accident or talking of a second's fall. I'll stick to the latter. Of course, rope drag may have an impact, which goes from helping the first resist the pull from the falling second (positive) to increasing the effective fall factor for the first (negative).

The Chief wrote: Factors of their own that totally and most assuredly insert a whole new mechanical twist on the rope slack and stretch issue.

If you are just trying to say that real-life falls involve all sorts of factors that a simplified model leaves out, then, yes, of course, that's another of those things even my neighbors' dog would know if they had one.

If you are implying that consequently simplified models have nothing to tell us, then you are wrong, as thirty years of involvement in scientific and technological research would no doubt teach you.

Instead of taking advantage of others' experience in fields in which you have none, you always try to put them down as if you felt belittled. I know it's part of your Internet persona, which I kind of like (well, most of the time) and I'm not much irked by it. But, don't you ever suspect it would be easy for me to put you down? On the contrary, I spent time sanitizing my reply of unnecessary sarcasm so that this discussion may be constructive.

So, now I await your answers to my questions.
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Postby brenta » Mon Jul 05, 2010 7:15 am

The Chief wrote:The latest DMM Sling test results prove that and quite frankly, are very mind boggling.

Actually, those results were mostly old news and well in agreement with the theory. The discussions they have stirred have been primarily on how realistic it is to use a rigid mass in place of a human body.

The Chief wrote:As the latest DMM tests show, the Dyneema Slings exert upwards of 22KNs of "static energy" before they blow.

The kN is a unit of force, not energy.
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Postby The Chief » Mon Jul 05, 2010 2:43 pm

brenta wrote: The discussions they have stirred have been primarily on how realistic it is to use a rigid mass in place of a human body.


My initial point exactly.

This particular test clearly shows the difference between types of slings, their dynamic (or lack of) impact within the systems and the addition of many more variables within your hypothetical equation.

Anyone taking falls on a regular basis would understand the factors in which this test shows and how this difference of material alone, can make a bigass difference on the final impact of a fall throughout the system.

"The question is: When the leader is pulled into the top biner by the falling follower, does (s)he stop right there, or does the rope start moving through the biner?

What is your argument? Do you have one? Are you suggesting that since you have no way to tell, nobody does?"



There is no solid answer as there are many variables that can be thrown into this equation. First being the difference of weight between the two individuals(obvious if the leader weighs more or less than the follower). The second being the amount of rope slack between the two. The third being what type of (Single or Double Rope System) Rope and Diameter etc. The fourth being if the Pro fails and if so, how many pieces within the system do thus elongating the fall etc. The fifth being rope drag as I mentioned. The sixth being how much rope is out. The seventh is the amount of "Air Time" versus frequent impacts during the actual fall. Etc etc etc.

Anyone that takes falls on a regular basis would clearly understand the "Insanity" I speak of. Far too many variables in the Real World of falling to allow for any set conclusion. Just can't be done.

Example: I took a 25 footer just last week on a slab route with the rope being out over 90' and I 10' above my last piece/bolt. My partner felt a very slight tug when it all came to an end. The week prior a 20 footer with almost the same results and the fall was on an overhanging crux with 100' of rope out clipped through 14 bolts.

Point: One can paint a picture on a canvass. But when the reality of it all comes true, that real picture becomes something that looks absolutely nothing like that which was originally painted.

5.8 was just a generic number that I threw into this equation as it is a conservative rating that I see most folks these days are climbing at out in the "real world" of trad.
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Postby mconnell » Tue Jul 06, 2010 2:32 am

The Chief wrote:[b]
[i]"The question is: When the leader is pulled into the top biner by the falling follower, does (s)he stop right there, or does the rope start moving through the biner?


There is no solid answer as there are many variables that can be thrown into this equation.


There is no solid answer as long as you ignore high school level physics. For the lead climber to stop and stay right at the biner, there would be infinite force applied to the leader, the rope, and the anchor. Figuring this out takes no knowledge of climbing. All the variables you mention would affect how far the leader fell past the biner, but not if.
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Postby The Chief » Tue Jul 06, 2010 5:11 am

mconnell wrote:"The question is: When the leader is pulled into the top biner by the falling follower, does (s)he stop right there, or does the rope start moving through the biner?"
The Chief wrote:

There is no solid answer as there are many variables that can be thrown into this equation.


There is no solid answer as long as you ignore high school level physics. For the lead climber to stop and stay right at the biner, there would be infinite force applied to the leader, the rope, and the anchor. Figuring this out takes no knowledge of climbing. All the variables you mention would affect how far the leader fell past the biner, but not if.


First of all, that is not relevant to the question posted.

If the Leader in a similar case relevant to the original question, weighs 200 or so pounds and the follower weighs 70-80 lbs less than that, the rope distance is 40-50 meters between them, lets say 10-15 pieces of solid placed pro, the Leader is 3-5' above the last placed piece, with substantial rope drag due to improperly placed runners, or lack of, this situ makes no impact on your high school level physics text book answer?

OooooKay!
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Postby SKI » Tue Jul 06, 2010 1:11 pm

brenta: 1 The Chief: 0

It's like watching a SNL skit between an astrophysicist and the captain of the football team.

Who gives a tish about all of the universalburificationtochaosasafunctionofnonlineartemporaldisplacements here. Bottom line, you embrace a certain level of risk when a team chooses to simul pitches- this freedom of choice is what makes the hobby/sport/way-of-life appealing to many an adventurer worldwide. No one gives a flying sh*t that you would rather solo 5.8+, go to supertopo to spray. No one wants to read deep into the X^2 = fCx^3 if X-.000000323=q crap. I want to see the accident report. I want to see what can be done to prevent this. I want to spread the word to my partners. Give me something palatable, digestible and easy to sh*t out. This thread should have been tamed a page ago.

Keep It Simple Stupid
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Postby The Chief » Tue Jul 06, 2010 2:03 pm

knoback wrote:"Life is short. The Art is long. Experience is difficult." Hippocrates said that about medicine, but it's true of climbing, too. The basic physics does matter, and if you don't understand it, you are going to f-up. You just have to avoid applying it too broadly. That seems to be Chief's basic point. Anecdotal evidence alone is just bullshit. "Fall on Rock/Ice, Failed to Place Adequate Protection" - this kind of discussion is way more useful than those sorts of insights from ANAM. Thanks for the analysis y'all.



Pheeeeeeeeeeeew.... thanks Knoback. Thought maybe any sorts out there with any experiential climbing and real good falling time may have actually gone astray.

It's not a matter of being right or wrong nor keeping score.

It's a matter or sharing real time experiences with all the variables for me. Not what is put down on paper, tested in the control enviro of a lab then written in "the text book".

Bottomline, each and every situ and scenario is completely different. As are each and every individual that ties into a rope and gets on the rock. Current time variables play a big factor in every incident in the end and none are the same as the other, none. Nor can a text book formula mathematical analysis answer be applied to them all. Impossible.

But some just don't get that side of the story I guess. They would rather pat one another on the back in agreement and not be the one to stand up and throw in the proverbial wrench named reality. Nope. That doesn't go well when shoulder to shoulder within the tribe.

If they did, they'd be banished to the corner or even tossed out the door and deemed a lunatic.....oh well.

As for the OP, remember, nothing is always what some or all may perceive it to be. Appears the latest reality of variables is a broken hold that may be the match which initiated this particular conflag.
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