RRC Archives

caribe wrote:Artsay: was your brake hand on the other end of the rope? How could this have happened if it had been? If it wasn't why wasn't it? If the brake end is unmonitored next time this could happen again.

Steep4me solution is to yell "Let go" while you are falling to your death instead of having the belayer minimize risk by doing it right.

WTF?

That's not my solution. I am just saying that the only time I have seen someone being dropped not hit the deck was when he yelled for the belayer to let go. All others hit the dirt. Obviously, keep your right hand in contact with the rope at all times. I have it running over my hand even when I am feeding out slack--then, just grab the rope (which always results in letting go of the cam--the most important part.

kek-san wrote:So just a dumb question. Are the GPS coordinates in the printed guidebook? Do first responders have GPS's or maps with GPS grid lines on them? Might eliminate some location confusion.

NOT a dumb question. WCSART and RRGMRT have gridded maps and GPS's that we use for search ops. If the GPS for an incident scene is given to a dispatcher, and if the dispatcher can accurately communicate the coordinates to the team, then that would be immensely helpful.

I have GPS coordinates in the print guide for some walls (mainly remote) and will be including more as I get them.

Okay, just one last comment on the whole gri-gri thing. I think you'll find that the amount of friction generated by an "un-cammed" gri-gri is quite a bit less than the amount of friction generated by an ATC just due to the angles involved and the way the rope threads through the gri-gri mechanism. So, even if you have your break hand on the rope appropriately, if that rope ever starts moving and the gri-gri cam doesn't engage for whatever reason it's going to be much harder to stop than with an ATC.

Disclaimer: this does not constitute an endorsement of "letting go".

ewaaser wrote:Okay, just one last comment on the whole gri-gri thing. I think you'll find that the amount of friction generated by an "un-cammed" gri-gri is quite a bit less than the amount of friction generated by an ATC just due to the angles involved and the way the rope threads through the gri-gri mechanism. So, even if you have your break hand on the rope appropriately, if that rope ever starts moving and the gri-gri cam doesn't engage for whatever reason it's going to be much harder to stop than with an ATC.

Disclaimer: this does not constitute an endorsement of "letting go".

This is true, but the only thing that has ever prevented the cam on a gri gri from engaging is someone or something holding it down. I have never heard of it just randomly freezing up.

steep4me wrote:

ewaaser wrote:Okay, just one last comment on the whole gri-gri thing. I think you'll find that the amount of friction generated by an "un-cammed" gri-gri is quite a bit less than the amount of friction generated by an ATC just due to the angles involved and the way the rope threads through the gri-gri mechanism. So, even if you have your break hand on the rope appropriately, if that rope ever starts moving and the gri-gri cam doesn't engage for whatever reason it's going to be much harder to stop than with an ATC.

Disclaimer: this does not constitute an endorsement of "letting go".

This is true, but the only thing that has ever prevented the cam on a gri gri from engaging is someone or something holding it down. I have never heard of it just randomly freezing up.

Apparently there is a way. Norma described it to me. Maybe she'll post but basically it has to do with the way you are standing and the angle which the rope is feeding into the device. She said someone in her gym can make it happen at will.

If you guys mean 'let go of the grigri' I am on board with that. The first reaction of someone who is startled is to do something instead of do nothing. If the importance of the brake to arrest a fall is wired as the only thing to do, that is what will get done reflexively. To do this effectively the brake hand has to always monitor the brake. This methods will work with any device.

When we stop in an automobile suddenly in a traffic situation we don't hit the accelerator and the brake because the brake is brain-wired as the stopping mechanism. When you use the grigri the brake hand on the rope hits the waist and the other hand is doing whatever except holding the cam open.

Wire the positive response to the brake hand only, monitor the brake rope by ALWAYS holding it when you belay and keeping at hand if you briefly have to pinch. These aspects are common to Petzl's two recommended ways to grigri.

I think these accidents are happening due to startled positive responses and sloppy belaying. The startled responses may be a function of the immediate movement of the thinner ropes through the device especially when the ropes are new.

Steep4me, I agree . . . in all these incidents the cams are being held open; this is grigri freeze; the devices are not failing we are.

caribe, i think we need to do some spearmentin! i'll let you be the guinea pig because you'd probably just crater a hole into the ground and come out unharmed and laughing like a hyena!

Since Michelle has mentioned my name...

To my knowledge there are 3 things that can cause a gri-gri to not engage (this is not gri-gri failure, it's a failure of the user to know what the gri-gri will and won't do).
1. pinch the cam (or hold the lever open) so that it can't engage. (we've all discussed this option ad nauseum)
2. have very low tension on the rope at the point where it enters the gri-gri, so there is not enough force (or torque around the pin) to cause the gri-gri to engage. Two ways this could happen: not enough weight (I really don't know how light a climber would have to be, and it probably depends on slickness and diameter of the rope, as well as any rope drag through the draws), or holding the rope above the gri-gri, thus putting a friction force on the rope which reduces the tension in the rope at the top of the gri-gri. (this possibility was mentioned by Wes and Gaar)
3. pull the climber end of the rope out of the gri-gri at a large angle to the usual. You are not holding the cam open, but it fails to engage because the pull is oriented along the axis of the pin and thus the torque around the pin is too low. If you hold a gri-gri so that it is flat (as though it were lying on a table, but *without* pinching the cam) and pull the rope straight up (i.e. at a 90 degree angle to what you usually pull at), it feeds easier than if the gri-gri is in it's usual orientation. Play with the angles a bit and you'll find that there are certain angles at which it is very easy to feed rope. With a lot of no-hands belayers, the gri-gri hangs from the harness at this funny angle. Most often the gri-gri rights itself, but I believe it's possible that if it is righted slowly enough that it may not lock (because by the time it is righted, the rope is already zipping through quickly so the acceleration (and thus force, torque, tension) is low). I had a near accident in which I nearly decked (new-ish gri-gri, 145 pound climber, 10.2 rope, loaded correctly, belayer had neither hand on the rope or the gri-gri). On realizing the gri-gri wasn't locking, my belayer reverted to his ATC skills and grabbed the brake end (and only the brake end) of the rope, and I stopped about 6 feet off the deck. I can come up with no other, simpler, more reasonable explanation as to what happened other than the gri-gri righting slowly from an unusual orientation (it was pointed out to me by a friend and is what I'd mentioned to Michelle.)

Every time this damn topic comes up, I spend a few more minutes contemplating the physics of it all. Then I stop myself because, as caribe and others have mentioned, the simple solution is to train an automatic response to grab with the brake hand and only the brake hand, in the case of a fall. Besides which, I have other things I need to be worrying about, like finishing my dissertation. And on that note, I intend never to wade into this discussion again.

regarding your #3 canuck, that brings up a question in my mind that i forgot to ask artsay. ARTSAY, when you belayed that day i'm curious if you had the locking carabiner through the belay loop or through the two harness loops?