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Posted
catbirdseat said:

snoboy said:

catbirdseat said:BTW, all bolts are omnis.

 

Don't get out much do ya??? wink.gif

What you talkin' 'bout, Willis? I been climbing all day today at Mt. Erie.

 

i believe he is talking about bolts not being omnidirectional... and he is right...

Posted
catbirdseat said:

Fence_Sitter said:i believe he is talking about bolts not being omnidirectional... and he is right...
For the purpose of stopping the "zipper effect", a bolt is omnidirectional.

 

I'm simply being a smartass.

 

Most bolts are wonderfully omni, but there are those ones that I wouldn't even trust to hold a downward pull, let alone an outward, that's the ones I was thinking of. shocked.gif

 

My reference to you not geting out was just the bitterness creeping out. hahaha.gif Oh, and I figured that maybe you hadn't seen enough of the old buttonheads.

Posted

I don't think it is rediculous to discuss the merits of reeling in. Like I said above, if you are ever belaying me, I want you to reel me in when I fall unless I am falling from an overhang where there is nothing to hit. Thus, as has been said already, there is some judgment involved and a discussion of the pros and cons is not a bad thing.

 

I don't put much stock in the numeric calculations, though, just as I dismissed similar mathematical speculation in discussing fall-factors or a prior discussion of whether double rope technique may foster a less dynamic belay. It is not a bad thing to try to quantify or rationalize the discussion, but the simple fact is that, when you get out on the cliff, there are many more factors than a simple equation might suggest. When I am leading, I try to put in a piece right off the belay - a good piece that is "omnidirectional" if possible, not because of a fall-factor issue and not so much because I am afraid that higher pieces might zip, but because one look at the situation usually suggests that it is easier for my belayer to set up to brace against a pull in a single direction and I want to know that the pull will come in the direction they are prepared for. My point is not to dismiss the discussion above, but to suggest that it is often much more intuitive, and much more obvious, than numerical calculations and point-counterpoint might suggest. On just about anything other than a sport climb, if I see my partner start to fall I'll be reeling in the rope - even if only a half of a pull - and he or she will be glad to fall eight feet instead of ten, or ten instead of fifteen, or whatever. And, by the way, I believe I might well be able to take in 3 reels and then be ready to catch the climber, using an ATC, in a situation where the fall lasted 1.3 seconds. Maybe not, but my point here is that after you have belayed falling climbers for a while, you get preetty good at it.

 

Posted

I apologize, I was not clear. I didn't mean "reeling in" was specifically ridiculous. I meant it is ridiculous that climbers who have many years of experience are debating how to do the most fundamental of life-protecting climbing skills at this point in their careers. smirk.gif

Posted

I have yarded-in rope to catch leader falls too, but it usually seems more like about an arm's length, not the 3 meters or so discussed here. I guess I would be hesitant to suggest such a practice for people learning to belay (in this forum perhaps?) when there is enough to keep track of as is when you are starting out. On climbs that are at the leader's limit, a little slack seems nice to give you enough time to assure the leader is not fighting for rope at a desperate clip as they go out of view.

 

Matt, since you have been belaying leaders on hard climbs longer than I have been alive I certainly yield to experience. grin.gif

Posted
iain said:

I apologize, I was not clear. I didn't mean "reeling in" was specifically ridiculous. I meant it is ridiculous that climbers who have many years of experience are debating how to do the most fundamental of life-protecting climbing skills at this point in their careers. smirk.gif

yellaf.gif
Posted
iain said:

Matt, since you have been belaying leaders on hard climbs longer than I have been alive I certainly yield to experience. grin.gif

 

Just don't take me to the sport crag. First of all, I'll whine about how steep it is and, second, I've been reeling in the belay for so many years that I just might do the wrong thing. Old habits die hard.

Posted
mattp said:I don't put much stock in the numeric calculations, though, just as I dismissed similar mathematical speculation in discussing fall-factors or a prior discussion of whether double rope technique may foster a less dynamic belay. It is not a bad thing to try to quantify or rationalize the discussion, but the simple fact is that, when you get out on the cliff, there are many more factors than a simple equation might suggest.
You can't dismiss the Laws of Physics.

 

Sorry.

Posted
Fence_Sitter said:

yeah but rarely do you just start free falling... you shoe rubber will slowly start to go or something like this...

So your buddy starts sketching, so you start yarding on the rope. Once you've taken up some of the slack, you're adding tension to the rope and effectively pulling him downward off his stance.
Posted
jkrueger said:

catbirdseat said:

What if you are using a GriGri?

Under what circumstances does one use a GriGri to provide a lead belay?

 

In my limited experience, quickly feeding large amounts of slack with a GriGri is not an easy task. When a leader wants slack, they want it now!!! and in those situations a GriGri seems to work against me more than it works with me.

 

I know, and have climbed with, people who use a GriGri to belay a leader. Actually, Erden used one when Goran Kropp killed himself. I don't like them when I'm leading; it seems that what you say is correct: it's a bit tougher to feed rope out quickly. I'm tall and make some quick, long moves and have felt the tug of my belayer not being able to keep up.

Posted

You can't dismiss the laws of physics, Attitude, but the "laws of physics" as you state them do not necessarly include all of the relevant factors. Your calculation of the rate of fall is only correct if you assume no friction and no resistence from a climber trying not to fall. If the holds on an overhanging wall suddently blow, your victim may fall at formula speed. However, if he or she desparately tries to cling to a lower hold after missing a reach, or if they fall on terrain that is not quite so steep and slide down the rock or maybe bounce off a couple lower footholds, they will not reach the formula speed quite so fast.

Posted
mattp said:

You can't dismiss the laws of physics, Attitude, but the "laws of physics" as you state them do not necessarly include all of the relevant factors. Your calculation of the rate of fall is only correct if you assume no friction and no resistence from a climber trying not to fall. If the holds on an overhanging wall suddently blow, your victim may fall at formula speed. However, if he or she desparately tries to cling to a lower hold after missing a reach, or if they fall on terrain that is not quite so steep and slide down the rock or maybe bounce off a couple lower footholds, they will not reach the formula speed quite so fast.

We're not in a court of law, counselor. I'm not claiming that one number fits every climbing situation. If your climber is "desparately tries to cling to a lower hold after missing a reach" and you're yarding on the rope, you could be pulling them off their stance. If not, then the clock starts when they pop off that hold and they are in free fall.

 

Actually my calculation overestimates the time to react and do something, as it doesn't take into account the rope. If you're yarding on the rope as it starts elongating, then you are adding to the force the pro must hold.

 

Posted

Excuse me for being so brash as to question your application of a numeric formula, Attitude, but I thought this was supposed to be a discussion of the pros and cons of the use a certain technique and you did in fact state that "on a vertical face, it takes an object about 0.6 sec to fall 10 ft" as if this were some inarguable and invariable fact. Please also excuse me for raising the same kind of counter-argument to your statement that reeling in the rope increases the force on the piece of gear that is going to hold the fall: I think that a shorter fall may well result in lower forces being applied, and the belayer who is watching the fall while they reel in the rope will indeed have locked off (and hence stopped reeling in) at the moment of the catch -- it is a natural reaction.

 

I don't purport to know everything about the situation and I have not studied the matter in any great deapth. However, if you are belaying me, I want you to be ready to try to reel it in.

Posted

Read the discussion, Flash. Attitude was responding to where I wrote:

 

mattp said:

only correct if you assume no friction and no resistence from a climber trying not to fall. If the holds on an overhanging wall suddently blow, your victim may fall at formula speed. However, if he or she desparately tries to cling to a lower hold after missing a reach, or if they fall on terrain that is not quite so steep and slide down the rock or maybe bounce off a couple lower footholds, they will not reach the formula speed quite so fast.

 

I do not question the "laws of physics." I question the application of those laws.

Posted

But Newtons laws cover everything being discussed here. Just add up all the forces on the climber, and divide by his mass, and you will know his acceleration. No problem applying it here. The real problem is calculating all the forces. Drag from friction, skidding on rock, falling while dynoing, the belayer pulling the rope, etc, etc, etc. In real life, it's impossible. This thread should be taken out and shot. thumbs_down.gif

Posted
mattp said:

Excuse me for being so brash as to question your application of a numeric formula, Attitude, but I thought this was supposed to be a discussion of the pros and cons of the use a certain technique and you did in fact state that "on a vertical face, it takes an object about 0.6 sec to fall 10 ft" as if this were some inarguable and invariable fact.

I agree it would take a longer time to fall and bounce 10 ft , but a climber-like object in free fall will take about 0.6 sec to fall 10 ft. Jump off a 10 ft high ladder. In ~0.6 sec you will hit the ground.

 

mattp said:

Please also excuse me for raising the same kind of counter-argument to your statement that reeling in the rope increases the force on the piece of gear that is going to hold the fall: I think that a shorter fall may well result in lower forces being applied, and the belayer who is watching the fall while they reel in the rope will indeed have locked off (and hence stopped reeling in) at the moment of the catch -- it is a natural reaction.

I'll have to think about this, as there are two antagonistic factors. A shorter fall means a lower terminal velocity, but a shorter rope means higher deceleration, therefore higher forces on the protection. Unfortunately, my analysis will involve physical modeling.

 

When is the "moment of the catch"? The freefalling climber reaches terminal velocity right before the rope goes taut, then decelerates until he stops moving downward, and then bounces for a short period.

 

mattp said:

-- it is a natural reaction.

It may be a natural reaction to try to do this, but I'll bet it is a learned behavior to do it correctly (i.e. without yarding too soon and pulling the climber off his sketchy stance or not having him effectively locked off at the "moment of the catch").

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