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Gear Failure on West Face Leaning Tower results in whipper.
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By Tabo
May 7, 2013
Hopefully someone checks this ... Using * Jay T's Impact Force Calculator
All that said, Jay's force calculator is of course theoretical. I haven't read what assumptions he makes about things like a somewhat upwardly mobile belayer.



These are the two threads that went into creation of the calculators. Look for posts between QTM and JT.

Quick discussion about the calc
rockclimbing.com/cgi-bin/forum...

Original thread.
rockclimbing.com/cgi-bin/forum...

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By Will S
From Joshua Tree
May 7, 2013
Torsional forces? On a rope-end biner that is floating in a sewn sling, not straight into a hanger? Just not seeing the mechanism there for any real torsion without the biner somehow being pinned.

Seems a little curious that 9/10 biner breaking stories I've read were all Mammut biners. Those Moses superlight wiregates were blowing up left and right a few years ago.

I'd chalk the whole deal up to freaky anomaly...but I also wouldn't be climbing on Mammut biners anytime soon either.

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By Travis Haussener
May 7, 2013
I'm saying a little Occam's razor mixed with Murphy's law...what could of went wrong did go wrong, and why?...really bad luck. You guys should have doubled down on black that day instead. The good news...a situation like this probably won't happen again for at least 30-40 years so we're all in the clear thanks for getting it out of the way for everyone else. Kind of like two commercial jets haven't crashed in the same week, month, year or whatever.

Glad you guys are ok. Did anyone go up and check the integrity of the bolts afterward. I know they're rated to elephant strength but given the string of events who knows?

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By Optimistic
From New Paltz
May 7, 2013
Were there any batch numbers visible on the failed biners?

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By slim
Administrator
May 7, 2013
tomato, tomotto, kill mike amato.
agree with willS, not seeing what will act as a reaction force to the torsion, as a sling has very little torsional stiffness.

also, interesting point about the mammut biners. that was my first thought also - seems like a LOT of broken biner reports i have read were mammuts, particularly moses, which unfortunately i have a bunch of....

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By Christiney
May 7, 2013
a beautiful line
Ah yes sorry about the bogus falling force calculator... I didn't know it was messed up. But it's crazy yet good that they would have the FF messed up (I think this crossed my mind but figured who would create a faulty calculator), if they didn't, it would be difficult to verify the kN force is also unreliable.

So many factors go into a real life situation. I have an engineering degree but when my classmate totaled his Corvette, we tried to calculate how fast he was going, or the friction of the road surface, or something, and the number came out to be completely unrealistic. So it was then we realized that the physics equations (sometimes you learn the simplified equations only to learn there are additional parts of the equation, e.g. E=mc^2 is only part of it, and the other parts "cancel" in a particular situation) often don't apply to real life where there are so many other factors involved.

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By ahh
From Bay Area
May 7, 2013
Hi everyone,

I'm Anthony, the climber who took the fall.

So I just want to clarify some issues and write up what I remember from the fall:

Gear:
If I recall correctly, I think there were actually 4 pieces between me and Shern before I fell. From top to bottom:
1. Purple C4
2. A marginal small nut (either a BD #4/5 or a DMM Peenut.)
3. A good nut (BD #7 I think)
4. The bolt
They were all extended with trad draws with dyneema slings, the Mammut wire gates (for gear side), and Mammut bent gates (rope end.)

The fall:
The nut that I was standing on popped right when I fifi'ed into the piece. Before I knew it, I was flying past Shern. Funny thing is, the fall happened so quick that I didn't even have the time to think about "oh shit it's over" or something (I'm sure Shern would probably think differently watching me falling onto the belay.) The fall felt like one single whip; I don't remember the pieces slowing me down much.

Some observations:
After I fell, the only pieces of gear still attached to the lead line were the rope-end biner from the C4 and the small nut (still attached to a draw) which got ripped out. The C4 (with sling) was found hanging on one of my aiders, not clipped to anything. The good nut (with sling) and the bolt (with sling) were still on the wall. The rope-end biners for both pieces were missing. One of them (the broken one) was later found by the party behind us.

Some other info:
- The rope was a 3-yo heavily used Mammut (yes another Mammut product!) Flash 10.5mm. According to this website , the impact force is 9.0kN.
- I'm 125lb. Aid gear is probably another 10lb.
- It can't be the static rope; the other end of the haul line wasn't on belay.
- We didn't use those rubber bands on our draws (who uses them on trad draws anyway?!)
- The pitch is diagonal (to the left) and about vertical.

Analysis:
Just like what Shern said, we think the rope-end biner from the C4 unclipped itself from the sling, and my aider proceeded to catch on the piece and rip it off. I then ripped out the marginal piece, and broke the biners on the lower two pieces.

I have thought hard and talked to a lot of people about this. The force generated from the fall can be particularly high due to the use of 1) an old, fat, stiff rope, 2) belaying with Grigri. Using an ATC might reduce the peak force, but of course, whether the belayer would be able to catch a huge whipper with an ATC would be a whole other story.

Just like many of you have suggested, comparing the broken biner with the BD QC lab report , it seems like the biners might be broken due to open gate failure, possibly due to gate fluttering, especially since they are solid gates. Or it might be broken due to some torsional forces.


Needless to say, Shern and I both felt extremely lucky that we walked away practically unharmed---if we were on something less overhanging, we would have been in big troubles.

Be safe out there.

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By Mark Hudon
May 7, 2013
On the North America Wall in 1977.
Dang, man, glad you both are well.

Make sure all this information, and the broken biner, gets back to Mammute!

FLAG
 
By Bill Lawry
From New Mexico
May 7, 2013
" Also--Anthony found the .5 c4 and draw minus the bent gate hung up on one of his aiders by some kind of luck. It was not clipped to it--it was tangled in it and he found it after the fall when he went to set up to jug. So on the way down, we figure his aider hooked the cam and pulled it as well."

Only thing that has come to mind for this is along the lines that you suggested ...

During the fall, aider snags on cam somehow and somewhere above the rope side biner (caught on cam trigger?). Cam gets pulled out of crack (high forces since rope is not involved). But the rope-side biner is slotted in a crack. Anthony's momentum pulls the draw across the bent gate and unclips it. Cam and sling remain tangled in the aiders. The draw's bent gate is eventually pulled free of the crack and is left free-floating on the rope. Any deep score marks on that free-floating biner?

And the above two unlikely things (snag plus bentgate slotted in crack just so) are followed by a third: gate flutter on bent gate associated with the bolt lower down.

And the above doesn't touch on why the rope-side biner of the lower nut failed (assuming that was not the nut Anthony weighted in the first place). Gate flutter again? Or also slotted just so in the crack?

Bizzare.

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By Bill Lawry
From New Mexico
May 7, 2013
JLP wrote:
For those who don't know what Mohr's Circle is and why the break has an angle to it, feel free to offer up other explainations on how ~1-2000 lbs of force (~open gate rating) went un-noticed by a 120 lb climber...

I qualify. :-)

My understanding is that breakage of gear / rock can occur which absorbs very little energy and so slows the climber down very little. In other words, the force to break something can be enough to cause failure but is quasi-independent of the actual energy absorbed from whatever applied the force.

A rope that stretches to failure is a great example of absorbing a lot of energy before breakage. A quick karate chop to a stack of bricks absorbs far less energy from the hand than more slowly pressing down on the bricks until they break.

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By Tabo
May 7, 2013
Caprinae monkey wrote:
... (sometimes you learn the simplified equations only to learn there are additional parts of the equation, e.g. E=mc^2 is only part of it, and the other parts "cancel" in a particular situation) often don't apply to real life where there are so many other factors involved.



The force calculators are based on RG's "Standard Equation for Impact Force". If you're an engineer, you might enjoy the read!

rockclimbing.com/cgi-bin/forum...

But yes, there are a lot of other factors that the calculators cannot take into account. The calculator gives a simple number which may be ballpark, but could be way off.

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By Kris Solem
From Monrovia, CA
May 8, 2013
Kris Solem climbing the route, 11-30-08. Photo by ...
I tried to bring this in upthread but it got lost in the frenzy...

And again while I have a mechanically adept mind I am no mathmetician, so I'll do the best I can.

As I read it, RG's paper deals with the impact force of a falling climber as if that climber were tied off to the gear which catches him - as if the rope from that gear to the belayer added no force to the gear.

My understanding is that the force of the falling climber and the force generated, coming from the other side other gear, by the belayer holding the fall are additive.

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By Don Ferris
From Eldorado Springs
May 8, 2013
Crux of ignominy
Check out this video from Black Diamond at :50.



Based on this I'd say the gate had to have been open.
Also no deformation on the nose of your broken biner hints to the open gate theory.

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By Optimistic
From New Paltz
May 8, 2013
There have been a number of posts here suggesting that there is something wrong with the practice of using any sling longer than a quickdraw (aka, a "trad draw"), in that the longer slings increase the chance of gate whip.

It seems to me like using a long sling to minimize drag is about as controversial at this point as using a harness or a nylon rope...ie, not at all. And if current carabiners are not adequate to deal with that eventuality, then it's the carabiners that are inadequate, not the slings.

Do a lot of people here feel that there's really some solid evidence to suggest that using a 24" or 48" sling without a locking biner is an unsafe practice?

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By redlude97
May 8, 2013
Optimistic wrote:
There have been a number of posts here suggesting that there is something wrong with the practice of using any sling longer than a quickdraw (aka, a "trad draw"), in that the longer slings increase the chance of gate whip. It seems to me like using a long sling to minimize drag is about as controversial at this point as using a harness or a nylon rope...ie, not at all. And if current carabiners are not adequate to deal with that eventuality, then it's the carabiners that are inadequate, not the slings. Do a lot of people here feel that there's really some solid evidence to suggest that using a 24" or 48" sling without a locking biner is an unsafe practice?

gate whip can be easily minimized by using wiregates which many already are

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By The Stoned Master
Administrator
From Pennsylvania
May 8, 2013
Day Lily.
Optimistic: Do a lot of people here feel that there's really some solid evidence to suggest that using a 24" or 48" sling without a locking biner is an unsafe practice?

I feel safe using a non-locking biner, no way am I dragging that many lockers. My experience tells me 99.99% of the time this is/will be adequate at least; I can't predict the future and the potential for something to malfunction/go wrong is always there.

To each his own though: safety is relative. Example: I tend to feel super comfortable using 2 bomber (solid rock + solid placement) pieces as an anchor. Many people would feel unsafe even though I feel safe.

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By Morgan Patterson
Administrator
May 8, 2013
Stoked...
Don Ferris wrote:
Check out this video from Black Diamond at :50. Based on this I'd say the gate had to have been open. Also no deformation on the nose of your broken biner hints to the open gate theory.


BD guy says they've never seen a closed gate failure in the real world since we can't generate forces that high so it must have been open gate failure. Sounds like case closed, time to get some wire gates... no?

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By The Stoned Master
Administrator
From Pennsylvania
May 8, 2013
Day Lily.
Ill take this opportunity to inquire: why are wire gates superior for crossloading, etc?

I use strictly wire gates myself but am unsure why they are tougher than the non-wire gates?

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By Bill Lawry
From New Mexico
May 8, 2013
Optimistic wrote:
Do a lot of people here feel that there's really some solid evidence to suggest that using a 24" or 48" sling without a locking biner is an unsafe practice?

Multi-pitch gear is my favorite climbing venue. I don't feel that sling extension without a locker is relatively unsafe.

In that climbing venue, needing to occasionally extend a sling is a given to anyone who has led much. I can imagine once in a while putting a locker on the rope-side biner of that piece placed early on lead, or on that early bolt with decking potential ... at the same time, I don't see myself doing that as a matter of habit.

I've never bought one of those bent gates. Sure, it is easier to clip the rope ... or inadvertently un-clip I guess. But aren't they also easier to wriggle off a bolt hanger?

Starting to replace my non-locker solid gates with the wire gate Wild Country Heliums. The heliums have an open-gate strength of 10 kN ... a little more margin than these bent gates (and many others) and still very light. At the same time, I wouldn't use them if I were lowering a lot on my draws as they can wear to a sharp edge. And since I generally don't aid climb, I'll continue to use a tube-style device.

It can't be said enough ... what a bizarre accident with so many failures. Glad Shern and Anthony are still with us!

Bill L

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By csproul
From Davis, CA
May 8, 2013
Summit of Wolf's Head with Pingora in the backgrou...
The Stoned Master wrote:
Ill take this opportunity to inquire: why are wire gates superior for crossloading, etc? I use strictly wire gates myself but am unsure why they are tougher than the non-wire gates?

In general, they're not better for cross loading. They may better in the major axis, and may or may not be better open.

Since we've been talking about Mammut: the Mammut Classic keylock and the wire keylock have the same gate open and miner axis rating, but the major axis is 1kN more for the wire gate. The Moses wire and the Element (solid) keylock are the same in each rating (23-8-8). The Bionic wire is stronger in the major axis, but the same open and weaker x-loaded than the solid gate.

The wires are (supposedly) less prone to gate flutter, so they may be more likely to stay closed than an equivalent solid gate.

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By csproul
From Davis, CA
May 8, 2013
Summit of Wolf's Head with Pingora in the backgrou...
Bill Lawry wrote:
.. I've never bought one of those bent gates. Sure, it is easier to clip the rope ... or inadvertently un-clip I guess. But aren't they also easier to wriggle off a bolt hanger? ...


Why would you ever put a bent gate on a bolt hanger?

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By The Stoned Master
Administrator
From Pennsylvania
May 8, 2013
Day Lily.
Thanks csproul! Good, clear explanation. Thanks man.

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By cjon3s
From Sterling, VA
May 8, 2013
Hanging at Seneca
Csproul, the trick I've seen for showing wire gates have less gate flutter is this...

Take a solid gate and smack the nose against your palm. You should hear the gate quickly open and shut again. Do the same thing with a wire gate and you should hear nothing.

All my trad draws are made from wiregates.

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By Mark Hudon
May 8, 2013
On the North America Wall in 1977.
The Stoned Master wrote:
Optimistic: Do a lot of people here feel that there's really some solid evidence to suggest that using a 24" or 48" sling without a locking biner is an unsafe practice? I feel safe using a non-locking biner, no way am I dragging that many lockers. My experience tells me 99.99% of the time this is/will be adequate at least; I can't predict the future and the potential for something to malfunction/go wrong is always there. To each his own though: safety is relative. Example: I tend to feel super comfortable using 2 bomber (solid rock + solid placement) pieces as an anchor. Many people would feel unsafe even though I feel safe.


It nice to see a bit of real world logic and calm thinking here.

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By Bill Lawry
From New Mexico
May 8, 2013
csproul wrote:
Why would you ever put a bent gate on a bolt hanger?

Good idea to clearly make that point here.

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