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jumaringjeff
Mar 8, 2005, 5:24 PM
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In reply to: oppose all stopper placements
completely unecessary and uses up gear that could be needed further up on the route or in your next anchor. moreover, how many times have you done this on a difficult lead in an awkward stance? in that situation, this approach could waste a lot of energy.
true, some passive placements need opposition, but not always.
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jumaringjeff
Mar 8, 2005, 5:29 PM
Post #52 of 63
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In reply to: What about those two bolts you used on the nth pitch of your last climb? Did you put those there? Who's to say those two bolts are any safer than pipsqueekspire's two cam belay? Sure, a correctly placed bolt... and all that.... BUT, did you correctly place it
this brings up a good point. I prefer to not trust my life exclusively to fixed gear (pitons, bolts, in-situ gear, etc.) which I always try to back up. however, the operative word here is try. as iamthewallress pointed out, climbing situations are not always perfect and thus you must make do with what the route offers.
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crotch
Mar 8, 2005, 6:12 PM
Post #53 of 63
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In reply to: That, If I recall rgold's argument correctly, is where the potential danger of an all-cam anchor lies.
Jay,
If anyone else posted this, you'd take them to task. You're citing a vague memory of a maybe post. Point us to rgold's post.
Empirically, it's difficult to put a truly lateral force on a cam. Try it sometime. If the crack allows, a cam will rotate so that the stem approaches the direction of pull. I'll allow for the possibility that the system behaves differently under larger loads than I could generate. In any case, I'd guess that the majority of falls on cams aren't perfectly in line with the stem and will generate some moment, and yet we don't hear about cams failing all the time.
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jt512
Mar 8, 2005, 7:19 PM
Post #54 of 63
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In reply to: In reply to: That, If I recall rgold's argument correctly, is where the potential danger of an all-cam anchor lies. Jay, If anyone else posted this, you'd take them to task. You're citing a vague memory of a maybe post. Point us to rgold's post.
No, Crotch, I wouldn't. I'm just being honest about my memory being vague. I couldn't find Richard's post; otherwise, I would have re-read it myself.
In reply to: ...yet we don't hear about cams failing all the time.
Yet we do hear about all-cam anchors failing sometimes, and one explanation that has been suggested for some of these failures is cascade failure due to a lateral force being applied to each cam as it fails in sequence.
-Jay
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brutusofwyde
Mar 9, 2005, 5:54 PM
Post #55 of 63
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In reply to: Whatever floats your boat. My anchor's job is to keep the team from getting ripped off in case of a factor two fall.
For example, like when the leader places a piece, climbs above it, and falls hard enough to place significant upward pull on all of your anchors...
then the piece the leader placed fails...?
Hmmm.
Sorry, but I think I'll have to decline that invitation to climb with you next weekend. I need to give my dog a bath.
Brutus
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murf
Mar 9, 2005, 7:19 PM
Post #56 of 63
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In reply to: In reply to: ...yet we don't hear about cams failing all the time. Yet we do hear about all-cam anchors failing sometimes, and one explanation that has been suggested for some of these failures is cascade failure due to a lateral force being applied to each cam as it fails in sequence. -Jay
Actually the main example being floated here is the Tahquitz accident. There is no over bearing proof that there was a three cam anchor failure in that incident. However, I believe that the start of the "three cam anchor" conspiracy was in that thread. The proponent of the view was Largo himself.
The only other one that I have heard of recently was the DNB anchor failure. It was supposed in that incident AFAIR that the belay was in a single feature that potentially expanded.
With all that, the inital premise of a cordellete equalized anchor being suseptible to cascading failure when weighted at medium to extreme angles makes some sense to me. However, it makes sense whether it is 3 cams, a cam/nuts, etc. If each placement is weak when weighted in the proposed direction, one could see the potential for cascading failure. Cams could be weak due to rotation ( most esp. bigger cams ), nuts could lift out and to the side, slung horns could pop. It would seem that an piece restricting moving for an upward as well as medium to large side-to-side motion would take care of this.
Something to think about, especially for those who don't put in many upward directionals into an anchor.
Murf
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omerdimsum
Mar 9, 2005, 7:33 PM
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Murf, you rock.
You in J-Tree this weekend?
JD
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cracklover
Mar 9, 2005, 7:41 PM
Post #58 of 63
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There are som very rare times when I would add an upward pull piece to an anchor. If the anchor was not sufficiently high enough above me, and a fall like the one you mention is possible, and the anchor is not able to take an upward pull... then I'd add an upward piece.
Typically, though, there is about five feet between me and the lowest of my anchor pieces, and I take a stance against the wall. You've climbed a good long time, Brutus. You ever hold, or see someone else hold, or even hear a reputable story about someone holding, a fall that rips them off their belay stance and up ten vertical feet?
Anyway, that wyde stuff kicks my ass, so I should probably thank my lucky stars that your dog needs a bath!
GO
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irockclimbtoo
Mar 9, 2005, 7:57 PM
Post #59 of 63
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ab
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brutusofwyde
Mar 9, 2005, 8:07 PM
Post #60 of 63
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In reply to: You ever hold, or see someone else hold, or even hear a reputable story about someone holding, a fall that rips them off their belay stance and up ten vertical feet?
Yes. Tangerine Trip. Leader: Craig Francois. Belayer, Eric Coomer. November 12, 1996 at about 09:20 am.
But, to answer this question in another way, I typically set the anchor such that upward extension is minimized. And the belayer has been jerked upward to the end of his leash many times. My first serious leader fall, on North Overhang in Josh circa 1973, jerked my belayer right off the ledge. Without a piece for upward pull, I would have decked, head-first, and my climbing career would have ended right there.
I stopped Eric Pearlman's 60-foot fall on the Salathe Wall, and in doing so was jerked to the end of my leash, the taut lead rope breaking my nose in the process. Upward travel on that one was about 7 feet.
Come to think of it, last fall I took was last November on Lava Falls in Pinnacles NM when a hold broke. Fell 20 feet, my unanchored belayer on the ground was jerked 10 feet into the air, and she stopped at the first bolt on that climb.
Don't feel too bad though. The wyde kicks my ess as well. Thats one of the reasons why I like it.
Brutus
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cracklover
Mar 9, 2005, 9:11 PM
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Wow, that's good food for thought. I'd never seen or heard of such before.
Now, if I've got a leash from my harness down and forward to the wall, and a lead rope up and forward to the first piece (or the "power point") isn't a hard fall going to cause you to pivot around the anchor point of the leash and slam hard into the wall?
Ah, well I suspect it kicks my ass harder than it does yours, though I'm pretty okay at Leavittation. But if you decide some day that the dog wash can wait, I'm willing to sign up for that ass-kicking.
GO
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brutusofwyde
Mar 9, 2005, 9:28 PM
Post #62 of 63
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In reply to: Now, if I've got a leash from my harness down and forward to the wall, and a lead rope up and forward to the first piece (or the "power point") isn't a hard fall going to cause you to pivot around the anchor point of the leash and slam hard into the wall?
The closer to the wall you are, the less horizontal force to slam you into it. Simple vector math, and the same reason why we want less than a 90 degree angle betwen the legs of an equalized anchor.
If you're good at leavittation, you could probably give me a few lessons.
Brutus
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murf
Mar 10, 2005, 3:41 PM
Post #63 of 63
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In reply to: Murf, you rock. You in J-Tree this weekend? JD
Should be there both days. Buy you a beer?
Murf
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