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yodadave
Oct 12, 2009, 10:23 AM
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So earlier this summer a friend and i got on a multipitch with my frankenrack. Going into it we knew that in order to protect the ~6th pitch crux we needed a #4 cam. The biggest cam i have on the frankenrack is a 2.5 so i was trying to think around the problem. What i came up with was 2 cams with a flake of rock in between them equalised so that in a fall they would hopefully push equally against the crack on the outside and the piece of flake in the middle.
Now in reality we decided not to bother protecting the crux even though it was above a ledge as the moves weren't that hard and they were relatively easily reversed.
However i've been wondering if the need arose whether this ghetto rig would have held?
So any thoughts or has anyone come up with the same rig?
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colatownkid
Oct 12, 2009, 10:44 AM
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yodadave wrote: So earlier this summer a friend and i got on a multipitch with my frankenrack. Going into it we knew that in order to protect the ~6th pitch crux we needed a #4 cam. The biggest cam i have on the frankenrack is a 2.5 so i was trying to think around the problem. What i came up with was 2 cams with a flake of rock in between them equalised so that in a fall they would hopefully push equally against the crack on the outside and the piece of flake in the middle. Now in reality we decided not to bother protecting the crux even though it was above a ledge as the moves weren't that hard and they were relatively easily reversed. However i've been wondering if the need arose whether this ghetto rig would have held? So any thoughts or has anyone come up with the same rig?
Theoretically that sounds okay, but I'd be worried about that flake of rock breaking.
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shimanilami
Oct 12, 2009, 10:52 AM
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If you pulled on it, wouldn't the inner lobes and flake just "roll" out?
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notapplicable
Oct 12, 2009, 11:06 AM
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I think the biggest problem with that scenerio (out of the 10 different things that could go wrong) would be the flake falling out and landing on your belayer. You would need some serious spring upgrades to make it stay put.
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notapplicable
Oct 12, 2009, 11:08 AM
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I guess you could wire both cams and the flake together beforehand and place it as a preconstructed apparatus. That would work.
I think.
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yodadave
Oct 12, 2009, 11:13 AM
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do i get to hear the other 9 things? 
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acorneau
Oct 12, 2009, 11:14 AM
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yodadave wrote: ... we needed a #4 cam.
[Edited 10-13-09 for correction!]
Just an FYI: A #6 Tricam fits the same range as a #4 C4, is half the weight (7.5 oz vs. 13.4 oz.) and half the price (~$45 vs. ~$85).
My biggest cam (#10 Metolius) goes up to 3.5" so I carry the #5, #6 and #7 when I might need the larger stuff.
(This post was edited by acorneau on Oct 13, 2009, 8:01 AM)
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djlachelt
Oct 12, 2009, 11:18 AM
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You are kidding, right? Have you given any thought as to you how you'd actually place it? Can you go hands free at that spot? Even with two hands I can't think how I'd place it, but maybe I'm not creative enough.
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yodadave
Oct 12, 2009, 11:21 AM
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like i think i said, the crux is right off a ledge and I'm pretty dextrous.
If i get a chance i'll rig it for a photo
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skelterjohn
Oct 12, 2009, 11:28 AM
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If there is an actual equilibrium here, under load, then it is an unstable one. IE this will not work. If you want to do the climb then run it out.
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charlie.elverson
Oct 12, 2009, 11:29 AM
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I think you would just hold the flake in place against the first cam then place the second one while holding the flake.
I would put good money on this falling apart really easily. say you place the cams perfectly and they do hold the block in place. I doubt there's much to keep the cams from walking. Even a tiny bit of walk in one cam would probably offset it enough that the flake would just roll out from between them (or so I'm guessing). Then if the flake stays in place until a fall, I think you would have the same issue if one cam shifted slightly more than the other when being loaded.
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cracklover
Oct 12, 2009, 12:05 PM
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Of course it wouldn't work. Good grief. They would just fall out. Do y'all have no ability to visualize concepts in your heads?
You could, however, nest two hexes. Not easy, but it can work.
Theoretically, you could even nest a hex and cam, but the hex would have to be sitting on a big nub for it to hold, and the chances of it holding a real fall are, IMO, pretty tiny.
GO
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yodadave
Oct 12, 2009, 12:21 PM
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ok so i just debunked my own theory.
it is very easy to set up but when you apply any force the cams act as if to push the rock out from in between them. It does look hilarious all set up though 
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shimanilami
Oct 12, 2009, 12:26 PM
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You could bring a ~4" long piece of 2x4 and effectively narrow the crack. This works on aid, at least. I don't know why it wouldn't work to hold a fall.
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cracklover
Oct 12, 2009, 12:26 PM
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Of course. Any force on either cam would result in a downward force on the rock in the middle, and there's nothing to oppose that force, so it would just fall out.
As a troll, this would have been much better played if you'd posted a pic first! You could have strung this out to five pages, no problem!
G
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yodadave
Oct 12, 2009, 12:35 PM
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your right in retrospect this could have been an awesome troll.
i just thought that the opposing cams would keep the rock centered
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tomtom
Oct 12, 2009, 3:10 PM
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Point one of the cams up and it should work fine.
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rschap
Oct 12, 2009, 5:41 PM
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Just bring up an old cast iron stove leg and protect it with that. Or you could also put a nalgine on the other side of the flake then you would only need one cam.
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Rudmin
Oct 12, 2009, 6:49 PM
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I have seen someone ball up their sweater and throw it behind their cam to keep it from walking around. The same kind of idea could help hold your contraption in place.
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ShibbyShane
Oct 12, 2009, 6:59 PM
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Dude, we need pictures!!!!!!!! 
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kachoong
Oct 12, 2009, 7:00 PM
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If you're gonna carry a rock just to wedge between two cams, why not just carry a rock to jam in and use as a chock?
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patto
Oct 12, 2009, 7:42 PM
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It would work as long as the contact points of both cams on the flake where parallel and in line with each other. Otherwise there would be a torque force on the flake.
I would suggest that this would make it next to impossible.
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notapplicable
Oct 12, 2009, 9:28 PM
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patto wrote: It would work as long as the contact points of both cams on the flake where parallel and in line with each other. Otherwise there would be a torque force on the flake. I would suggest that this would make it next to impossible.
I tell ya, pre-rigging is the key. Just grab the tape out of your pack, run it through the lobe holes on one unit, around the flake and through the lobe holes on the other unit. A few wraps and your golden!
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scottydo
Oct 12, 2009, 11:06 PM
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i've heard of people doing this with small two by fours ( i think ) to protect really wide spots. not sure i'd be comfortable with using a flake of rock.
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king_rat
Oct 13, 2009, 2:31 AM
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It might work. It would probably hold body weight at least, though I think falling on it would probably result in it twisting round and pulling lose. I suppose if it’s all you have and you’re facing a ground fall, then it may be worth while, but I think that the effort expended would be greater then the level of protection gained.
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j_ung
Oct 13, 2009, 9:19 AM
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^^
That's what I pictured when I first read the OP. I've done similar things before involving loose-but-semi-fixed flakes in cracks, but I confess, I have no idea if it would have worked if needed. At the time, I imagined it might come down to leverage (were the cams placed so as not to simply see-saw the flake out) and the degree to which they were actually equalized, rather than just in theory.
Edit: This might be an interesting experiment next time I see a similar situation low enough to the ground to bounce test over a crash pad.
(This post was edited by j_ung on Oct 13, 2009, 9:21 AM)
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csproul
Oct 13, 2009, 9:26 AM
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I recently read a big-wall trip report where the climber didn't have a large enough cam to aid up a wide section. He used a board up against the side of the crack to effectively make the crack smaller such that the cam he did have would fit. It worked for aiding, but I am not sure I'd trust it for fall protection.
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altelis
Oct 13, 2009, 9:28 AM
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All PTFW claims that are part of an edited post will be held as suspect.
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altelis
Oct 13, 2009, 9:45 AM
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Worthless without screen shots!
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