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healyje


Dec 30, 2012, 12:04 AM
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More than adequate.


jt512


Dec 30, 2012, 12:12 AM
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healyje wrote:
More than adequate.

What minimum braking force do you believe that a held-open braking-assist belay device (especially with a thin, slick rope) provides?

Jay


JimTitt


Dec 30, 2012, 12:44 AM
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jt512 wrote:
healyje wrote:
More than adequate.

What minimum braking force do you believe that a held-open braking-assist belay device (especially with a thin, slick rope) provides?

Jay

That´s easy, I´ve just pull-tested some. A quick and dirty test as I´m not going to set-up the standard pulling angle that is usually used so this one is straight through and the values are a bit higher than usual, probably ca.20%.
Used 10mm rope, I don´t own any thin single ropes.

Ratio of braking force to hand force (force multiplication).

Cinch 1.3:1
GriGri 4.2:1
For comparison:-
ATC XP Low friction mode 6:1
ATCXP High friction mode 7.1:1

I haven´t a Faders Sum available but on that the rope does go straight through without impediment so it would be even worse than the Cinch which puts a slight kink in.


healyje


Dec 30, 2012, 12:52 AM
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More than enough in combination with the braking over the thigh.


jt512


Dec 30, 2012, 1:13 AM
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Re: [JimTitt] Cinch Issues? [In reply to]
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JimTitt wrote:
jt512 wrote:
healyje wrote:
More than adequate.

What minimum braking force do you believe that a held-open braking-assist belay device (especially with a thin, slick rope) provides?

Jay

That´s easy, I´ve just pull-tested some. A quick and dirty test as I´m not going to set-up the standard pulling angle that is usually used so this one is straight through and the values are a bit higher than usual, probably ca.20%.
Used 10mm rope, I don´t own any thin single ropes.

Ratio of braking force to hand force (force multiplication).

Cinch 1.3:1
GriGri 4.2:1
For comparison:-
ATC XP Low friction mode 6:1
ATCXP High friction mode 7.1:1

I haven´t a Faders Sum available but on that the rope does go straight through without impediment so it would be even worse than the Cinch which puts a slight kink in.

JIm, by any chance do have, or can you determine, the force multiplication factor for an old-school ATC-dash-nothing with a 10-mm rope?

Jay


healyje


Dec 30, 2012, 2:55 AM
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Re: [jt512] Cinch Issues? [In reply to]
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You guys can run all the math and drop tests you want, but in the end it's a pretty Edisonian, real world, you-can-do-it-or-you-can't proposition and I can assure you it's no problem with a rope down to about a 9.8 or so. Below that down to about an 8.8 I'd probably start restricting devices down to the grigri2 and Eddy for still being able to do it.


JimTitt


Dec 30, 2012, 3:19 AM
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First the disclaimer!
With belay plate tests you need to do them absolutely identically as the angle between the braking strand and the loaded strand is critical, use the same rope all the time as well and the same speed. Obviously you can only accurately compare devices in the same test so comparing different tests is a bit of a lottery though generally the ATC in its various forms appears somewhere so gives a sort-of benchmark.

The original ATC has been tested quite a lot though, the DAV drop tests gave a coefficient of 6.8:1 and the CAI (the Italians) got 7:1. Both of these are higher than I got (5.8:1) but they used lower hand forces than I did which changes things a bit and they are drop tests not pull tests which I and BD used.
I get substantially the same results for an original ATC and an XP used in the low friction mode.


deltav


Dec 30, 2012, 6:58 AM
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Re: [deltav] Cinch Issues? [In reply to]
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OK here is some more information:
The device was 1-2 years old
Minimal wear on the device
The belayer has 3-4 years experience with no record of climbing related mistakes

For those of you who claim that you can hold a fall with an assisted locking device loaded backwards; have you actually tried this? I have, and find it extremely difficult to do so even in a top top setting. I imagine I couldn't even come close in a lead fall...

Those of you who have been able to recreate such issues, can you be more specific as to how?

Thanks,


lonequail


Dec 30, 2012, 7:10 AM
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Re: [deltav] Cinch Issues? [In reply to]
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I had a Cinch not properly lock on me several years ago. The Cinch was relatively new and not worn.

The incident was in a gym, the leader was on a near horizontal roof a few feet out from his last clip. I watched him get sketchy, knew he was coming off and I was ready for the catch. The rope pulled through maybe 20 feet before locking up, fortunately still off the deck. As this happened I grasped harder with my break hand and got some rope burns. Note that I am positive that my break hand was completely on the rope, not on the device or interfering with the proper function of the device, and it was positioned below the device. I’ve climbed for a long time (well before active belay devices were available) and instinctively bring my hand down to catch falls.

After playing with the Cinch I see how this is possible. The situation:

• The device is rotated 90 degrees clockwise from its fall catch position
• The belayer’s break hand is low
• The face plate is in the position rotated clockwise, not in the locked position

With this setup, the rope can run straight through the slot without going around the pin, and the plate does not pinch the rope. Unless there is an action, such as rope friction, it is possible for the devise and the face plate to stay in this configuration and not lock up! The belayer’s break hand can keep the face plate from rotating and pinching the rope. Note that for my incident, the fall was soft without a jerk that might have rotated the device and made it lock up.

To avoid this failure mode, the belayer would need to be sure that the device was always rotated counterclockwise, as it is when loaded and locking the rope. However, the realities of belaying are that the device will flop around in different positions as the belayer gives rope, takes in slack, and prepares for a fall. Alternatively, if the belayer were to bring their hand up (not down) in the event of a fall, the device would rotate counterclockwise and lock. However, this is counter intuitive, not standard practice, and relies completely on the action of the device rather than (at least the backup of) the belayer’s break hand below the device.

Diagrams/photos are probably needed for a full explanation – maybe later. It’s probably impossible to know if this action was the problem in my incident, or if something else happened. Regardless, my later experiments convinced me that this failure mode is possible. I do not trust the Cinch and will not use one again.


healyje


Dec 30, 2012, 3:05 PM
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Re: [deltav] Cinch Issues? [In reply to]
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deltav wrote:
For those of you who claim that you can hold a fall with an assisted locking device loaded backwards; have you actually tried this? I have, and find it extremely difficult to do so even in a top top setting. I imagine I couldn't even come close in a lead fall..,

Let me be clear, no one is going to stop a fall on a free-running autoblocking device with just their hands - it isn't going to happen. In order to stop a fall you have to have the ingrained instinct of braking falls over your lower hip / upper thigh regardless of the belay device in use. The lack of that instinct isn't so much generational as device-driven. If you come up learning on autoblocking devices as your primary belay device you are just not likely to develop such an ingrained instinct.


deltav


Dec 30, 2012, 4:34 PM
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Re: [healyje] Cinch Issues? [In reply to]
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I know what you mean and I still don't think it is really possible without friction from some sort of device.


csproul


Dec 30, 2012, 4:51 PM
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Re: [healyje] Cinch Issues? [In reply to]
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healyje wrote:
jt512 wrote:
There are lots of climbers harboring the illusion, for instance, that if they were to thread a Grigri (I) backward that they could catch a fall. They're wrong.

They're not if they know how to belay. There isn't an autoblocking device made I couldn't hold a leader fall just fine with the device held open.
[:roll:]


jt512


Dec 30, 2012, 4:54 PM
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healyje wrote:
deltav wrote:
For those of you who claim that you can hold a fall with an assisted locking device loaded backwards; have you actually tried this? I have, and find it extremely difficult to do so even in a top top setting. I imagine I couldn't even come close in a lead fall..,

Let me be clear, no one is going to stop a fall on a free-running autoblocking device with just their hands - it isn't going to happen. In order to stop a fall you have to have the ingrained instinct of braking falls over your lower hip / upper thigh regardless of the belay device in use. The lack of that instinct isn't so much generational as device-driven. If you come up learning on autoblocking devices as your primary belay device you are just not likely to develop such an ingrained instinct.

No one is going to stop a fall on a free-running Cinch by braking over their hip either. As Jim's numbers show, an open Cinch is essentially no belay device at all.

Jay


danabart


Dec 30, 2012, 5:15 PM
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I think you're off on this one Joe. I've done plenty of hips belays, caught leader falls with them and so on. Consider the hand position in which these devices are used. If one of these auto whatevers is threaded wrong or open for some reason, the belayer is not going to be able to hold the rope in a way that is equivalent to a properly done hip belay. Wouldn't be enough friction and the wrist would not be in a position of strength.


healyje


Dec 30, 2012, 5:29 PM
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I brake over my hip/leg on all falls regardless of device type and I can assure you it's enough to stop a fall reliably regardless of anyone's numbers. We've seen the numbers / drop test business not being aligned with reality on the rope-slippage-through-devices issue. I've held endless long and hard falls, including FF2 falls, without gloves over thirty-eight years and have never experienced any significant rope slippage of any kind.


JimTitt


Dec 31, 2012, 12:25 AM
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Re: [healyje] Cinch Issues? [In reply to]
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However using your personal experience as a bench mark to either design equipment or recommend techniques is neither desirable nor sensible.
The various hand strength tests take of nescessity only a sample of the population and have to use some kind of analysis to provide a solution which works for most people, not all. The most commonly used sample (K & K Mauthner) shows a wide range of abilities and depending on whether you use the average with a standard deviation (DAV/Randelzhofer) or the better 95% of the population (CAI) we get a range in which most are operating. It is clearly stated that there are no limits outside this range (obviously 0 is really the lower limit).
So we work with a solution which applies to nearly everybody, not an elitist one which few can achieve, I personally can hold nearly 3 times the value used by the CAI and twice that from the DAV but don´t expect everybody else to be able to do so.
Somewhere out in the world there will may be someone who can stop a fall just holding the rope in one hand but this doesn´t mean we should ALL belay with this method since we would end up with a climbing population of just one person.
The climbing community could use your position of "I can do it so everybody else must be able to" by looking at Adam Ondra and saying "he climbs 5.15 so scrap all routes below this grade", a position equally as stupid and unreasonable as yours.


healyje


Dec 31, 2012, 4:18 AM
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There is absolutely nothing whatsoever special about my hand strength. If anything I'd guess I'm on the light side of the bell curve. In fact, there's nothing exceptional at all around what I'm saying. What I can do, however, and do fast and reliably by instinct, is brake a fall over my hip / thigh such that my hand ends up 180 degrees around behind the top of my thigh.

My main point is braking falls over the hip / thigh in that manner is essentially no longer done or practiced which I consider quite unfortunate in a world of 'almost always' autoblocking devices. If you delegate the braking function to an autoblocking device 100% of the time and the device can't reliably autoblock 100% of the time (for whatever reason) then it's hard to escape the conclusion you're gambling.

Let's put it this way, how often do you take your brake hand off the rope when a partner is resting on your grigri? Hopefully never, because your hand is backing up the blocked device. Not braking falls over your hip / thigh means during the fall there is no backup to the device catching the fall - it either works or it doesn't and if it doesn't someone's going for a ride.

Personally, being old, I just don't trust any device that much.


(This post was edited by healyje on Dec 31, 2012, 4:20 AM)


JimTitt


Dec 31, 2012, 9:20 AM
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Curiously enough the hip belay has never been in use in Europe, at least I´ve never seen it described or used, when I started it was a shoulder belay which died out rapidly except for top-roping and the waist belay which was the standard in the mid-sixties. Neither of course being realistically suitable as a back-up strategy for any kind of device.
The issue of residual braking force for the various types of device is of interest since clearly an unexpected drop in braking performance is very likely to have severe consequences, some designers are bothered about this and some clearly not. The solution is more likely to be a technical one since most of the current designs could at least be considerably improved with little effort, teaching generations of climbers another technique is unlikely to be a great success.

Happy New Year!


Kinobi


Jan 4, 2013, 5:44 AM
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myusername


Jan 4, 2013, 7:16 AM
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Kinobi wrote:
Provided that I am the distributor of the Cinch in Italy.
Provided that my opinion are not necessarly the same as Trango's.
Provided that I have done two videos on how to use the Cinch, that have seen about 40K times.

Kinobi's alternate video instruction

http://www.trango.it/video/usarecinchweb.mov

Looks scary to me. I'm thinking the official Trango video is probably best.


patto


Jan 4, 2013, 9:40 AM
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healyje's thighs:


healyje's thighs:


Seriously though. Braking around the thigh really doesn't add that much friction. Anybody who thinks they can hold the several hundred kg of a severe fall in their hands without a proper friction device is kidding themselves.


(This post was edited by patto on Jan 4, 2013, 9:44 AM)


Partner cracklover


Jan 4, 2013, 10:49 AM
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lonequail wrote:
I had a Cinch not properly lock on me several years ago. The Cinch was relatively new and not worn.

The incident was in a gym, the leader was on a near horizontal roof a few feet out from his last clip. I watched him get sketchy, knew he was coming off and I was ready for the catch. The rope pulled through maybe 20 feet before locking up, fortunately still off the deck. As this happened I grasped harder with my break hand and got some rope burns. Note that I am positive that my break hand was completely on the rope, not on the device or interfering with the proper function of the device, and it was positioned below the device. I’ve climbed for a long time (well before active belay devices were available) and instinctively bring my hand down to catch falls.

After playing with the Cinch I see how this is possible. The situation:

• The device is rotated 90 degrees clockwise from its fall catch position
• The belayer’s break hand is low
• The face plate is in the position rotated clockwise, not in the locked position

With this setup, the rope can run straight through the slot without going around the pin, and the plate does not pinch the rope. Unless there is an action, such as rope friction, it is possible for the devise and the face plate to stay in this configuration and not lock up! The belayer’s break hand can keep the face plate from rotating and pinching the rope. Note that for my incident, the fall was soft without a jerk that might have rotated the device and made it lock up.

To avoid this failure mode, the belayer would need to be sure that the device was always rotated counterclockwise, as it is when loaded and locking the rope. However, the realities of belaying are that the device will flop around in different positions as the belayer gives rope, takes in slack, and prepares for a fall. Alternatively, if the belayer were to bring their hand up (not down) in the event of a fall, the device would rotate counterclockwise and lock. However, this is counter intuitive, not standard practice, and relies completely on the action of the device rather than (at least the backup of) the belayer’s break hand below the device.

Diagrams/photos are probably needed for a full explanation – maybe later. It’s probably impossible to know if this action was the problem in my incident, or if something else happened. Regardless, my later experiments convinced me that this failure mode is possible. I do not trust the Cinch and will not use one again.

Yikes! Thanks for sharing the only actual first-hand example of the failure in this thread, along with your analysis.

GO


healyje


Jan 4, 2013, 1:53 PM
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Re: [patto] Cinch Issues? [In reply to]
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patto wrote:
Seriously though. Braking around the thigh really doesn't add that much friction. Anybody who thinks they can hold the several hundred kg of a severe fall in their hands without a proper friction device is kidding themselves.

You'd actually not want big thighs or hands. You want a sharper bending surface around the top of your thigh and you don't want your hand so large you can't bring it around behind your thigh.

But seriously, though, one of us actually has experience holding lots of long and hard leader falls with no friction device at all and one of us is talking out their ass.


patto


Jan 4, 2013, 3:09 PM
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I've never had the experience a catching whipper fall from an elephant, but I know it isn't going to work out well.

Seriously though, not having experience in something (catching big falls without a functional friction device) ,does not mean somebody is "talking out of their ass".

I'm sure I've agreed with you on other topics, I'm sure you have alot of good experience to contribute to the discussion. But this time just because I disagree with you, doesn't mean im talking out of my ass.


healyje


Jan 4, 2013, 3:33 PM
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patto wrote:
I've never had the experience a catching whipper fall from an elephant, but I know it isn't going to work out well.

Seriously though, not having experience in something (catching big falls without a functional friction device) ,does not mean somebody is "talking out of their ass".

I'm sure I've agreed with you on other topics, I'm sure you have alot of good experience to contribute to the discussion. But this time just because I disagree with you, doesn't mean im talking out of my ass.

Well, the problem I have here is you keep making assertions as to what is or is not possible or what will or will not work out well when you have no experience at all in the matter. I've held lots of really hard lead falls with no belay device whatsoever and with no rope slippage and know exactly how much friction is provided by the body braking I use. It's not a 'sort of' or 'kind of' or 'maybe' sort of deal and not one that is too painful or unreliable - if it was I wouldn't have used it then or still occasionally now.

In short, belay devices are a convenience, they are in no way necessary. It's an entirely modern illusion that they are somehow necessary to a 'safe' belay.

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