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Neoshade
Aug 18, 2011, 7:14 PM
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One last point on the whole "a knot is equalizing" thing.
Why are people getting all panties-in-a-bunch about a knot slipping a little and cinching down a little? This happens during loading of every single knot ever!!
The Double 8 for a little rig on one leg only needs about 1inch of slip between the loops to equalize from a 3 foot movement in Master Point down below! This is TINY and normal for all knots as they come under load!
What I'm saying is, that when the double 8 tightens up under load - as all knots do - it actually equalizes a LOT during this 1 inch of rope movement through the knot!
Go try it out. Hang it on a wall and pull it off axis, and fall as hard you can on it. The darn thing works! And, again, I'm only offering it up here for use in only small loops on one leg on an anchor: For a situation where the tiny amount of rope taken up in a knot during loading is enough to get the equalizing you're looking for. And this knot does it.
Again, it's just an alternative to clove hitches, and I'm looking for constructive criticism and input, I'm sorry for making any claims other than "What do you think of this?"
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Neoshade
Aug 18, 2011, 7:19 PM
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vencido wrote: If I get hooked up with a partner that has a big hunk of accesory cord tied together with a double fisherman's and then extra fisherman stopper knots (tied 3" from the end of the main knot) I'll quickly come to the conclusion that he tends to waste time and overthink things.
hahaha, That was the first cordalette I ever tied. I did it while killing time sorting my gear. Seriously, who cares?
Thanks for trolling jerk.
(This post was edited by Neoshade on Aug 18, 2011, 7:28 PM)
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JimTitt
Aug 18, 2011, 7:34 PM
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Before you make claims about how the knot equalises under load perhaps you ought to actually test it under real loads, 6kN is generally considered the minimum one to use.
Iīve already know (and have given you) the information of how to calculate why it wonīt in any way, shape or fashion begin to be remotely equalised so I donīt need to bother.
For your sliding X variant the need to slide through 3 karabiners makes it a similarly useless proposition and it would be more effective (though still not equalising) if you short-hitched into the karabiners. You can replace the funny 8 with an overhand.
If you want dynamic equalisation then friction must be eliminated.
Use the rope or clove hitch, you may love your funny 8 but Iīve never found any useful application for it in 44 years climbing, instructing, 7 years living aboard a sailing boat and 15 years in the marine industry. The same goes for the sliding X.
Jim
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Neoshade
Aug 18, 2011, 7:46 PM
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Thanks for the link to the DAC info, BTW, but I can't read German, and unfortunately Google won't translate a PDF.
I'd love to see the research though, and figure out how to measure 6kn myself under a dynamic load. (static weights are pointless)
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JimTitt
Aug 18, 2011, 8:45 PM
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A force is a force but thatīs going to get complicated, for their tests you need the dynamics anyway.
But being a good chappie I have actually wandered over to my workshop, beer in hand (itīs 10.30 at night here) and pull-tested your knot theory.
As usual (for us anyway) we set up a 60° two-point anchor and start pulling with the centre-point offset to the side (and line of pull) and see what the loads are on each anchor point. This gives the ratio of the unevenness of the load you will get in practice with dynamic equalisation (if thatīs the word to use).
I pulled at 6kN with 6mm cord.
Simple equalisation (just on a single strand, no X or whatever) - 1.53:1
3 karabiner sliding X as in your example - 3.71:1
Funny 8 - 7.25:1
So now you can put this into your diagrams and work out the loadings you get in reality when you start your equalisation from one side or the other. And then you will appreciate why 95% of the systems are worthless and the rest not much better. And why "nearly true equalisation" has to be accompanied by "using a collection of large and very expensive pulleys throughout the system".
Jim
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Neoshade
Aug 18, 2011, 8:54 PM
Post #31 of 88
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The use of a double 8 for the entire anchor can be found in disucssion here:
http://www.rockclimbing.com/...ew_flat;post=2127276
[edit] In discussing the use of a double 8 as an anchor...
USnavy wrote: This method is similar to what Beth Rodden uses and well... she climbs 5.14 trad. I took Beth's multi-pitch class in Red Rocks last month and she taught us to build the anchor using the rope and tie a double loop figure eight similar to whats in the picture.
I'll take Beth Rodden over many other people. (and further innuendo)
(This post was edited by Neoshade on Aug 19, 2011, 2:10 PM)
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JimTitt
Aug 18, 2011, 9:26 PM
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Using an Alpine Butterfly to belay is a lot older than me, it has no relevance to what you are doing as far as I can work out.
Quoting US Navy wonīt get you any bonus points or do anything for your credibility!
Jim
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rgold
Aug 18, 2011, 11:18 PM
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If you need to get a 5.14 climbed, you probably want Beth Rodden over Jim Titt (sorry Jim, I don't even know you, just guessing...) But if you want authoritative advice about anchors, not only do you want Jim Titt over Beth Rodden, I'd guess Beth Rodden isn't on any conceivable short list.
Most climbing "knowledge" is seat-of-the-pants BS, typically justified by, "I've never heard of procedure XXX ever faiiing." There is little reason to believe that very good climbers know any more about the subject than the average climber. They are both going on a combination of folklore and tradition.
Part of the lesson of all this is that there is a wide range of procedures, many of which are very far from optimal, which are still good enough most of the time, primarily because "most of the time," circumstances do not provide a severe test.
With nylon rubbing on nylon, the SSE is even further from optimal then similar concoctions. It probably won't engender a total catastrophic anchor failure, because such things are very rare under all circumstances. But if your anchoring philosophy involves doing what you can to stack the deck in your favor, then the SSE doesn't seem like a sensible option to me.
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patto
Aug 18, 2011, 11:31 PM
Post #34 of 88
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Neoshade wrote: Also, sorry Patto for getting preachy and aggressive when I was treating John Long's work and the extension testing like gospel and just beating the bible at you. 
Neoshade wrote: Well shucks, I feel like being a John Long believer is now a black mark upon my soul. :-/
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Neoshade
Aug 19, 2011, 3:17 AM
Post #35 of 88
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JimTitt wrote: Using an Alpine Butterfly to belay is a lot older than me, it has no relevance to what you are doing as far as I can work out. Quoting US Navy wonīt get you any bonus points or do anything for your credibility!
Uh, Jim, you lost me. Is the thread and discussion I referenced talking about an Alpine butterfly? I don't think it is. The discussion I linked to and quoted USnavy from is about the Double Figure 8 or "bunny ears" knot that I've used here in the rig.
Alpine Butterfly is a rather elegant knot too though.
And BTW thanks for the testing. 
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Neoshade
Aug 19, 2011, 3:07 PM
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Wow Jim,
I just took a look at your credentials and other forum posts.
I tip my hat to you sir! I was not not aware that was arguing with a professional! :)
So you're telling me that a carabiner Sliding-X like I used in my second set of photos (right, 3 carabiners in total, counting the pro) doesn't equalize at ALL when the Centre-Point / Master-Point is pulled to one side before loading??
Wow. OK.
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acorneau
Aug 19, 2011, 3:34 PM
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This whole mess reminds me of something some students came up with for anchoring a double-line rappel...
(This post was edited by acorneau on Aug 19, 2011, 3:35 PM)
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Triple Double8.jpg
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Neoshade
Aug 19, 2011, 4:08 PM
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Ha!
OK, that's a little ridiculous!
This setup is an obvious FAIL with it's terrible angles, but it looks like it's quick to tie, super easy to adjust, and otherwise bomber.
(Except for one other thing - I don't much like the double 8 in primary anchor rigging, for lack of redundancy in the strands, especially if they can slip at all under load.)
Anyone else?
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JimTitt
Aug 19, 2011, 4:56 PM
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rgold wrote: If you need to get a 5.14 climbed, you probably want Beth Rodden over Jim Titt (sorry Jim, I don't even know you, just guessing...) But if you want authoritative advice about anchors, not only do you want Jim Titt over Beth Rodden, I'd guess Beth Rodden isn't on any conceivable short list.
Ha! If you want a 5.14 bolted then Iīm your man, climbing-wise Iīm a few digits short somewhere. Though if I can have the age-related allowance at one number grade per decade Iīm on!
(Iīm really a 58 yr old onsight 5.11dīish bumbler who should be 10kg lighter and Iīve been like that for 40 years now so no prospect of sudden improvement).
Iīm on holiday for 3 weeks in the world centre of trad climbing (the UK) where cordalettes and their relatives are looked upon as madness and only for beginners so Iīll try to bash out an article on anchoring and the physics.
Jim
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JimTitt
Aug 19, 2011, 5:44 PM
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Well Iīm a professional when it comes to making some types of climbing gear (at least the tax man says so) and I know a lot about frictional dynamics in climbing gear, whether there is any money in anchoring systems is debatable!
The killer all the way through the whole equalisation thing is the resistance over the karabiner or ring, 1.6 is the magic number (roughly) and is the factor (usually called the karabiner factor) you always end up using when you look at the approximate forces on one side against the other. And until this is eliminated you cant get equalisation, add another turning point and you add another lot of "unequalisation".
Your sliding X has three turning points and a quick test gave a karabiner factor of 3.71:1 (for the relatively thin 6mm cord and 12mm diameter karabiners a single bend gave 1.53:1 and if you multiply 1.53 X 1.53 X 1.53 you get 3.58 so obviously it was near enough).
So when you load the centre point slightly off to one side with say 5kN one of the anchors gets 3.94kN and the other gets 1.06kN, whether you call that equalised is a matter of opinion! And donīt even look at an Alpine Equaliser!!!
Your Funny 8 was a dead man walking because I knew beforehand that the resistance of nylon on nylon is far higher than over metal so it would be horrific, with our 5kn load you will get 0.6 on one side and 4,4 on the other, basically you could just tie to one piece and chuck the other one down the cliff.
I shall try to find time to write an article and show how to simply calculate all this but then what will happen to the endless creativity we see?
Jim
Jim
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hugepedro
Aug 19, 2011, 6:26 PM
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Neoshade wrote: Ha! OK, that's a little ridiculous! This setup is an obvious FAIL with it's terrible angles, but it looks like it's quick to tie, super easy to adjust, and otherwise bomber. (Except for one other thing - I don't much like the double 8 in primary anchor rigging, for lack of redundancy in the strands, especially if they can slip at all under load.) Anyone else?
Think you got that backward. There is nothing wrong with the angles, and it's ridiculous overkill so "quick to tie" would not be one of its features.
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JimTitt
Aug 19, 2011, 7:45 PM
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Itīs a sort of chicken and egg thing really. In all my climbing career I can only really remember one fatality from a failed belay in the sense we are discussing because typically cragging one has more time and spends more effort on getting a worthwhile belay. And anyone who is playing for months in his bedroom working out these systems is going to be so anal about his gear placements that nothing will ever fail anyway.
On the other hand a friend of mine has had 8 belay failure fatalities in one year in his local area because it is mountaineering where clip the peg and go is normal, replacing the rotting pegs with bolts cured that but that is another whole ball game.
So one set of climbers will probably be safer than another, even though the system itself isnīt but there we are.
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Neoshade
Aug 19, 2011, 9:38 PM
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+1 drecter & Jim.
Thanks again for the friction info Jim, I think it'd be helpful for a lot of us "bedroom anchor geeks" to have some hard info to work with. My claims were based on nothing more than familiarity with the knot in general, and yanking as hard as I could on it. Nothing above a 1 Kn.
So I guess I can only offer the double 8 for use as an alternative to cloves, (not for any "self equalizing" abilities) being faster to tie and adjust for myself, but probably not for others.
FYI - I get into this stuff out of curiosity and study. When I'm at the crag I still use the classic simple methods I was taught
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patto
Aug 19, 2011, 10:08 PM
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The thing is that cordalettes can do a pretty good job of equalising everything.
If its just two pieces horizontally in line with each other then predicting the fall line and trigonometry will ensure 'even enough' loading.
Three pieces are much harder to equalise. But personally I have no issues with 50:25:25. This obsession with perfect equalisation was created by JLong.
The thing is that I currently don't even own a cordalette. I build my anchors out of climbing rope. Its just as fast, more flexible, stronger and dynamic. I create a statically equalised anchor and its totally bomber.
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vencido
Aug 19, 2011, 10:19 PM
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patto wrote: I build my anchors out of climbing rope. Its just as fast, more flexible, stronger and dynamic. I create a statically equalised anchor and its totally bomber.
90% of anchors I make I just use the rope.
But occasionally I know from the parking lot that I'll be leading every pitch, or that I'll need to lead the second half of the route.
On these occasions I bring two cordolettes with me.
Do the never ever cordolette people just use slings if they will be leading everything?
Or do you swap ends or something else I'm not naming?
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patto
Aug 20, 2011, 7:53 AM
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vencido wrote: Do the never ever cordolette people just use slings if they will be leading everything? Or do you swap ends or something else I'm not naming?
I currently don't own a cordalette so I have no choice but to use the rope. I currently have no plans to buy another cordalette. (Slings rarely suffice for the trad anchors where I climb.)
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rgold
Aug 20, 2011, 2:52 PM
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I never swap ends. I'll carry cordelettes for long multipitch routes and for inexperienced seconds, but what I do at each stance is governed by the complexity of the anchor. With simple anchors and on shorter routes where an extra minute is far from critical, I'll usually just rebuild the anchor for the second.
Since I use half ropes for everything, anchor-building is simplified considerably and rebuilding really takes very little time. One reason it is simple and fast to rebuild a double-rope tie-in is the absence of the almighty but rarely essential power point. Independent connections to parts of the anchor can be undone while still leaving the party tied in. (The most obvious example of this is the two-piece anchor with one rope tied to each piece.)
Another thing that helps with changeovers is having an installed tether on the harness. I clip mine to the best single piece (but loosely enough so that if the anchor is loaded it will be the ropes that take the load). Being clipped this way means that anything can be undone and changed and I'll still be tied in. It also means, in the ordinary case of shared leads, that as soon as the leader is off belay I can start taking apart the anchor and so will usually be very close to ready to climb (just the final piece to clean) as soon as they are on belay.
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mbrd
Aug 21, 2011, 4:35 AM
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coming in late here, so sorry if i am asking stupid questions, but are you saying you initially clip the most solid piece and the rope when you arrive at the belay? good plan...
and regarding the issue of cleaning up the belay as the lead has swung, you're just talking about scrapping what isn't gonna help henceforth in a fall, right? i mean you're not bagging the whole station, are you?
i guess i know that how much prelim cleansing of the station one can do depends a lot on the upcoming pitch, but i am wondering if there are more efficient transitions i could be considering.
the embarrassing thing is that all this brainwork is happening on my couch- and my part is not even really good brainwork. it's also a sort of mediocre couch...
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rgold
Aug 21, 2011, 4:54 AM
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mbrd wrote: ...are you saying you initially clip the most solid piece and the rope when you arrive at the belay?
Yes. But the rope is eventually set up to take any belay load. If I am trying for speed/efficiency and am climbing with experienced partners, I'll say "off belay" as soon as I'm tethered in to the first (good) piece, so that the second can take me off belay and start getting ready to climb while I'm setting up the rest of the belay anchor.
mbrd wrote: ...and regarding the issue of cleaning up the belay as the lead has swung, you're just talking about scrapping what isn't gonna help henceforth in a fall, right? i mean you're not bagging the whole station, are you?
I'm not sure we understand each other here. When the tethered-in leader calls "off belay" and continues to set up the belay anchor, the second takes the leader off, puts on or tightens up their shoes, puts on the pack if there is one, and dismantles every part of the anchor except the single piece they are tethered to. When the leader takes up the rope and calls "on belay," the second un-tethers and removes the final piece and is ready to climb.
I should emphasize that the procedure is for experienced parties on long routes who consider time savings to be worth a small extra risk. There is a period when both leader and second are both tethered to a single piece with neither belaying. There is no reason to be doing this on short multipitch climbs.
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