Multipitch W/ a GriGri. Safer to Not Clip the Belay Station?

rockandice.com/climbing-gea…

rockandice.com/climbing-gea…

Deja vu. Personally, I thought the R&I's reply a bit too simplistic.

Agh! Beat me to it!

Xam wrote: I am confident we don't disagree on the elementary physics. But thank you for copying this info here for others to see.

Well maybe you should disagree. The account is full of vague statements verging on misunderstandings, the most prominent of which is equating impulse and force.

Xam wrote: It wasn't a question...I was just trying to understand what you were trying to say because isn't very clear. I agree that mechanical advantage is not the correct term. You can't just apply it because it sounds correct. It has a meaning. But thank you for the discussion.

This is simple. We're talking about a leader fall on a multipitch rock climb, but comparing a shock load on the bolted belay to the weight on the bolted belay being relieved when the belayer gets picked up. What'd I miss?

These cam-action belay devices are two separate parts, connected to make a pivoting action. You can hold the device in your hands and move the cam forward by pulling on the lever. When catching your leader with the first placement of pro being no more than 2 ft away from you (unless you lower yourself from your belay station), the only thing that the rope pulls on is the moving part on the belay device. Your body weight continues to pull the body of the device the other way. For the device to get held open there'd have to be a way for the rope to pull the bottom part of the belay device in the same direction. That's how the cam-action belay device manufacturers can produce these things--there's nothing other than two opposing forces pinching a rope between two surfaces. No matter how hard something pushes against the cam, our fat ass will remain pulling the rest of the device the opposite way.

Same goes for catching a leader DIRECTLY on your cam action belay device. There will never NOT be two opposing forces. I just think it's more dangerous to set it up that way.

I'm out!

This is what a fixed point belay (usually with a munter--google it) is for. It's super simple with a bolted anchor. You can use an ATC too, but the story above of using a Grigri off the anchor to belay a leader seems very ill-advised.

rgold wrote: Well maybe you should disagree. The account is full of vague statements verging on misunderstandings, the most prominent of which is equating impulse and force.

I simply don't have the energy. I leave it in your capable hands. Maybe while you are at it you can explain to Paul Hutton how a fixed point belay will not get 'shock loaded' by a lead fall, assuming that fall is on a dynamic rope?

All,

I think if you draw the free body diagram with the climber and belayer at rest you will see that the in the scenario where the anchor is clipped, the load is approximately 2x (so there is mechanical advantage).

I like the OPs original question about being drawn into the anchor, but think the answer is more situational.... personally I do not often clip the master point.

However, if one of my three pieces comprising the anchor is a solid placement (or a bolt) and is high enough I will clip that as my first piece of protection. I guess this is based on being more afraid of a FF2 event that the piece pulling or the bolt breaking.

I can also seeing lead belaying directly off the anchor, perhaps with a munter having an advantage when swinging leads. (See Mike Barters video on youtube.com/watch?v=1CbFpRP…)

-Brian

Brian Banta wrote:All, I think if you draw the free body diagram with the climber and belayer at rest you will see that the in the scenario where the anchor is clipped, the load is approximately 2x (so there is mechanical advantage).

You mean the load at the lead bolt, right? Still no mechanical advantage for the belayer (or the fixed point belay). At best, for friction free (i.e. an ideal pulley) you get 1:1 (no advantage). For friction, you get less than that. But don't take my word for it:

Consider lifting a weight with rope and pulleys. A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a single pulley. It has an mechanical advantage (MA) = 1 (assuming frictionless bearings in the pulley), moving no mechanical advantage (or disadvantage) however advantageous the change in direction may be.

en.wikipedia.org/wiki/Mecha…

The fact that the bolt takes 2x the force does not provide mechanical advantage.

Ted Pinson wrote:Fairly relevant: mountainproject.com/scripts… I'm curious how likely the whole "Grigri pinned in the draw, pushing open the lever" scenario actually is. Has this been tested?

Yes, it's happened numerous times in the real world and people have decked because of it. There are people on this very forum that have experienced or otherwise witnessed it. It's common/ important enough that at one point Petzl was warning about the danger of pining the cam open against a quickdraw and the warning was illustrated in the user manual. One thing I can say for sure if that if the cam is pinned against something, such as the rock, the device absolutely will not lock and the GriGri is a really shitty ATC. The other dude claimed he caught a fall with a GriGri threaded backwards--great, there are tons of belayers who havent and their partners paid the price for it by decking. Also, no one is catching a legit FF2 with the GriGri threaded backwards, no matter how strong they may be. It's hard enough to catch one with an actual ATC.

Good to know. I believe this was also one of the reasons Petzl warns against using Grigris for direct belays.

Ted Pinson wrote:Good to know. I believe this was also one of the reasons Petzl warns against using Grigris for direct belays.

I am not aware that Petzl does not recommend the GriGri to belay a leader directly off the harness on a multipitch. Where do they say that?

Not off your harness, directly off the anchor (autoblock mode):
petzl.com/CA/en/Sport/Belay…

Petzl wrote:Take up slack regularly as the second climbs, always holding the brake side of the rope. This method of belaying the second is less than ideal: in this position, the GRIGRI's braking action on the rope is not optimal (especially with thin ropes). In addition, the risk of blocking the cam is greater. We therefore recommend a different technique, using a redirect point.

Did everyone completely miss Slim's post about the solution to this issue? DING DING DING! Cuz he nailed it.

1) I always use a GRIGRI when doing hard muiltipitches.

2) Unless the climbing is very easy, I always use the anchor as my first piece of pro to prevent a factor two. Unclip this once one or two more solid pieces have been placed.

3) If a high fall factor fall is likely, or if I need to ensure a more dynamic catch, I POSITION THE BELAYER WELL BELOW THE ANCHOR.

Josh Janes wrote:Did everyone completely miss Slim's post about the solution to this issue? DING DING DING! Cuz he nailed it.

My question was not about what options exist when I think a FF2 is likely. I am aware of the several options that exist when an FF2 is likely, including the one you mentioned and several others that were not mentioned. The question is about when an FF2 is not likely, should one clip the belay or not. So far I am at the conclusion that clipping the belay when using a GriGri makes the situation more dangerous, not less, because a GriGri is capable of catching a FF2 directly, but if your device gets locked in the open position by a draw, which seems like a very plausible scenario, you're going to take a ride. The exception to this would be if the climber can get a first piece in rather early on, in which a fall possibly wouldent generate enough force to lift the belayer to the draw. However, once the climber is well out of the belay, there is more than enough energy involved to pull the belayer straight into the draw.

20 kN wrote: However, once the climber is well out of the belay, there is more than enough energy involved to pull the belayer straight into the draw.

I would think that your tie-in to the anchor would catch you before you got sucked into the draw. If not, then tie in shorter once the leader gets several good pieces.

No I get it: You're asking which is less horrific, option A or option B, and I'm saying if either is a possibility maybe you should be thinking option C. But it sounds like you have your answer: A GRIGRI is capable of catching a FF2 but will do squat if it can't lock properly.

Ted Pinson:

Those Petzl instructions are for belaying the seconder... from the top. The question you were answering (and one of this thread's topics) is about belaying a lead climber, using a GriGri, not using your harness. He's going up, you are down at the last belay station, and you are hands free. Your GriGri is clipped to the master point, not to you.

Ugg...yet another thread debating how to use a flawed device the "right" way. The Gri is way past its prime, time to move on.

Ted Pinson wrote: I'm curious how likely the whole "Grigri pinned in the draw, pushing open the lever" scenario actually is. Has this been tested? Also curious if the "panick mode" feature on the new Grigri will fix this...

Anecdotally, I've seen this happen. It was at the Motherlode (Tuna Town if you know the routes there) at the RRG, with a ~165 lb climber and ~110 lb belayer, during an intentional victory whip, of all things.

Basically, the climber pulled the belayer up to the first draw, and both her small hand AND the grigri were pulled into the quickdraw somehow. The grigri was stuck in the open position, she was able to lower him to the ground, then it took five minutes or so for several of us to get her unstuck from the biner. Definitely could have been tragic if the belayer had been less on it.

As for the original poster, I can't think of too many occasions in which the risk of a grigri getting stuck in a biner is greater than the risk of an ugly FF2. Factor twos are infinitely safer when belayed with assisted locking devices, but even still a FF2 is a big fricking deal and really dangerous.

I would always insist on the climber clipping into something on the anchor- maybe just a single biner instead of a quickdraw or extendable if you're really worried about the grigri being too close to the anchor. And, just like 90% of the time, you can go ahead and unclip the lead line from the anchor once the leader has clipped 2 or more pieces of pro anyway.