Another Accident due to mis-use of the Gri-gri

Christian wrote:I think they're homophones, actually.

Not that there's anything wrong with that.

rgold wrote:Slim, the only thing we know (and, frankly, the only thing you know) is that you haven't encountered the problem. You have an explanation for this, based on something you call seriousness, whose implication is that anyone who does lose control under the rare circumstances that seemed to obtain in this accident is not taking their job seriously. You are turning what could be nothing more than your good fortune into some sort of personal virtue and then suggesting bad things only happen to those who are not sufficiently virtuous.

BS, you know and i know that if a belayer has a solid grip on the brake end this won't happen. you can fully open the lever and if someone falls you will still catch them.

Mort - even with a fully open grigri it really isn't that much different than using an atc, provided that your hand is adequately positioned and you have a solid grip on the rope.

Eric Engberg wrote: brake - can no one spell?

good call on the spelling.

csproul wrote: Not that there's anything wrong with that.

Lol!

Always thought homonyms were the same spelling and different meanings, like "bank" of the river and "bank" where the money is.. but,

"In non-technical contexts, the term "homonym" may be used (somewhat confusingly) to refer to words that are either homographs or homophones.[1]"

slim wrote: BS, you know and i know that if a belayer has a solid grip on the brake end this won't happen. you can fully open the lever and if someone falls you will still catch them. Mort - even with a fully open grigri it really isn't that much different than using an atc, provided that your hand is adequately positioned and you have a solid grip on the rope.

this needs to be tested with real world whippers

ill see if i can get 2 other climbers to help me ...

one tapes the cam open on the grigri and uses it as an ATC ... the other does a backup belay with some slack

ill need to take decent whippers, not just be lowered

now to find 2 climbers for the test out here !!!

and ill need a thin rope too !!!

slim wrote: BS, you know and i know that if a belayer has a solid grip on the brake end this won't happen. you can fully open the lever and if someone falls you will still catch them. Mort - even with a fully open grigri it really isn't that much different than using an atc, provided that your hand is adequately positioned and you have a solid grip on the rope.

Wow, that's a bold claim. Lucky for you, it's an easy one to prove. Just post a video of you catching a lead fall while holding the lever on the Grigri fully open. That will convince the non-believers.

Mort wrote:What if you seriously grab both?

It will still lock, simple as that.

aikibujin wrote: Wow, that's a bold claim. Lucky for you, it's an easy one to prove. Just post a video of you catching a lead fall while holding the lever on the Grigri fully open. That will convince the non-believers.

I agree. I have serious doubts that most would be able to arrest a fall with an open Grigri. As I've said before, I've tried it with a Grigri threaded backwards and it did not provide adequate friction IMO. I have little reason to believe that a Grigri with the cam held open would behave any differently. I'd love to see someone test this.

reboot wrote: It will still lock, simple as that.

You may be wrong in some cases, simple as that. Glad you and Slim won't be belaying me.

Some open-cam Grigri tests would be interesting. But in addition to using a new slick thin rope, make sure to use a 100 lb belayer (under the hypothesis that grip strength is very roughly proportional to body weight). Climbing is a strength-to-weight game, but when it comes to hanging on to a loaded rope, strength is all that matters, lighter people will need more help from their device, and one of the factors influencing the choice of a Grigri over an ATC is precisely the concern that the belayer might have trouble with control.

Before lobbing leader falls (which sounds dangerous to me---what if the belayer can't hang on) I'd try some static tests. The climber hangs on a single strand on their device (atc, Grigri with cam taped open) as if rappelling, and weight is added to the braking strand until the climber is held in position without slipping. The climber's feet can be inches above the ground so no risk involved. I'm not able to do this myself right now or I'd do that test. The ratio of the climbers weight to the holding weight would give an estimate of the "force multiplying factor" for the belay device (a linear concept that has been used in a number of papers in spite of appearing, according to some of Jim Titt's tests, to be not at all linear).

This could at least settle the question of whether or not an open Grigri provides at least ATC-level braking.

rgold wrote:Some open-cam Grigri tests would be interesting. But in addition to using a new slick thin rope, make sure to use a 100 lb belayer (under the hypothesis that grip strength is very roughly proportional to body weight). Climbing is a strength-to-weight game, but when it comes to hanging on to a loaded rope, strength is all that matters, lighter people will need more help from their device, and one of the factors influencing the choice of a Grigri over an ATC is precisely the concern that the belayer might have trouble with control. Before lobbing leader falls (which sounds dangerous to me---what if the belayer can't hang on) I'd try some static tests. The climber hangs on a single strand on their device (atc, Grigri with cam taped open) as if rappelling, and weight is added to the braking strand until the climber is held in position without slipping. The climber's feet can be inches above the ground so no risk involved. I'm not able to do this myself right now or I'd do that test. The ratio of the climbers weight to the holding weight would give an estimate of the "force multiplying factor" for the belay device (a linear concept that has been used in a number of papers in spite of appearing, according to some of Jim Titt's tests, to be not at all linear). This could at least settle the question of whether or not an open Grigri provides at least ATC-level braking.

Done.

I set up a rappel in my basement with an old-model grigri with its lever tied open with a cam strap (like on a crampon). There was no visible movement of the cam.

Rope: a short length of 9.8mm in okay condition. Not fuzzy yet.
Climber weight: 130lb
Rappel glove: OR Airbrake that fits me well

With the rope running off the end of the device, I found it impossible to stop with a single brake hand. I just slowly slid down the rope. I could stop by squeezing hard with both hands.

With the rope running off the right side "rope guide", I could stop with one hand but just barely. Having the rope run off of the sharper left side provided better braking, but it still took a lot of work to stop.

I am not going to try dynamically loading the device, as it was hard enough to brake when gently easing my weight into the rope. I get way, way more friction from body belay/rappel techniques than with a disabled grigri.

I rapped off Pente (120') in IC years ago on an 8mm tag line using a 1st gen Gri gri. I never felt concerned. I did allow the cam to work though.

nicelegs wrote:I rapped off Pente (120') in IC years ago on an 8mm tag line using a 1st gen Gri gri. I never felt concerned. I did allow the cam to work though.

You should always lower off in IC. Its way safer. At least that's what some guy on the internet said.

Not the issue nicelegs.

Dobson wrote:I am not going to try dynamically loading the device, as it was hard enough to brake when gently easing my weight into the rope. I get way, way more friction from body belay/rappel techniques than with a disabled grigri.

You have to brake the rope across your hip as if you where doing a hip belay.

rgold wrote:Not the issue nicelegs.

The issue is that none of this is the issue. I might as well have added that hippo milk is pink, it's just as on topic as any of these "experiments".

The grigri was set up properly, therefore we know that it was used improperly.

Slickness of the rope, weight of the belayer, and diameter probably contributed. No matter how many pages this topic gets to, we all know that had the belayer held on with her brake hand and stuck her left hand up her nose (as per MY recommended technique) that nothing would have happened. All else is hand wringing and I figured you were above that (I'm not, but I'm a poor role model).

nicelegs wrote: No matter how many pages this topic gets to, we all know that had the belayer held on with her brake hand and stuck her left hand up her nose (as per MY recommended technique) that nothing would have happened. All else is hand wringing and I figured you were above that (I'm not, but I'm a poor role model).

No, we don't all know that. Petzl apparently hasn't gotten the memo, for example. And I'm not "handwringing," whatever that is supposed to mean. My original comment way back was that I thought it possible that a belayer might not be able to control a fall if the Grigri cam didn't engage, with their brake hand properly applied. I still think that is a very real possibility, and Dobson's test seems to indicate my concerns are reasonable. Could he turn out to be some kind of outlier? Perhaps some more people will report.

rgold wrote: My original comment way back was that I thought it possible that a belayer might not be able to control a fall if the Grigri cam didn't engage, with their brake hand properly applied.

Maybe, maybe not, but we don't know the part in bold for any of the accident cases brought up in this thread.

I'm perfectly willing to concede uncertainty. But the fact that we don't know is not equivalent to the unfounded assumption the brake hand was not properly engaged and so the belayer was at fault. And the fact that we don't know does not mean that the Grigri cannot slip in a way at least some belayers cannot control.

In the case that started this, the belayer's hand was badly burned, for whatever you want to do with that piece of information.

reboot wrote: Maybe, maybe not, but we don't know the part in bold for any of the accident cases brought up in this thread.

You wouldn't know that for ANY accident that might be brought up and given the reactions on this thread, you/we probably wouldn't believe a belayer who claimed to have a properly applied brake hand. That's kind of the point. Without better testing, we're relying on anecdotal accident reports. And in the absence of better testing, I'd rather err on the side of caution and assume that under certain circumstances, the Grigri cam CAN be overridden, and that if it is, there is not adequate friction to arrest a fall.