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flyinglow
Mar 2, 2006, 10:16 PM
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In reply to: Is that powerpoint knot a bunny-ears without "folding" the upper loop over the rest of the knot and in behind it? That's how I see it..... anyone?
^ that one looks like a lot of work to use up 2 more biners than charlesjmm's current setup, it is pretty though. just my opinion.
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healyje
Mar 2, 2006, 10:33 PM
Post #427 of 915
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flyinglow,
It is just a non-commercial version of an Alpine Equalizer (AE). It is quick and easy to set up once you know the powerpoint knot. It is functionally equivalent to kachoong's rig. Several of the AE rig variants here are just that - Kachoongs, mine, and the one with the alpine butterflies all just differ in how the "power point" is constructed.
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healyje
Mar 2, 2006, 10:38 PM
Post #428 of 915
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flyinglow,
I put that one up and is just a non-commercial version of an Alpine Equalizer (AE). It is quick and easy to set up once you know the powerpoint knot. It is functionally equivalent to kachoong's rig. Several of the AE rig variants here are just that - Kachoongs, mine, and the one with the alpine butterflies all just differ in how the "power point" is constructed. Also, I like the one-biner version better but overall prefer the equalette and mousolette to all these AE rigs including my own.
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flyinglow
Mar 2, 2006, 10:51 PM
Post #429 of 915
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Has anybody tried the setup i put in a couple pages back? I realize now it was kind of hidden within another post....
anyway here it is in recap:
1. start with a single biner AE,(like charlesjmm's "step 2", no limiters or twists in the cord,yet).
2. tie a "loop on a bight"(figure 8 or butterfly loop about 6 inches long) just to one side of the power point on EACH piece of cord passing through the power point.
3. clip all the loops through the power point in addition to the original cords.(loops should bear no weight, but sit slightly loose, they're there for backup and only bear load if a piece blows or cord is cut.
only takes a few seconds longer than charles' and gives limited extension no matter how many pieces blow (obviously, not if they all go, but even if all but one piece blows, you only get about a foot of extension.)
it can be used in any configuration,(horizontal, vertical, etc) and should give the same or better load sharing than charlesjmm's because it's not so tuning sensitive, it's almost totally self equalizing(within limits, defined by how big the backup loops are.) With practice, it may be quicker to set up because you don't have to unclip any of the pro once it's placed.
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flyinglow
Mar 2, 2006, 10:57 PM
Post #430 of 915
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healyje: i totally agree with you, was just wondering what the point of the fancy knot was aside from using up cord and biners.
I couldn't see any advantage to it.
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kubi
Mar 2, 2006, 10:57 PM
Post #431 of 915
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In reply to: In reply to: Is that powerpoint knot a bunny-ears without "folding" the upper loop over the rest of the knot and in behind it? That's how I see it..... anyone? ^ that one looks like a lot of work to use up 2 more biners than charlesjmm's current setup, it is pretty though. just my opinion.
That knot is really easy to tie, stretch out a cordalette and fold over about 1.5 feet at one end, so that you have two double loops, then tie a figure 8 on a bight on that folded over section.
Uh...that doesn't make much sense, but if you try it on your own it's really easy. The beauty of this anchor, as I see it, is that you never need to untie that knot. Once you get your protection in it just takes a few clips and you are all set-up, no knots to fiddle with.
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healyje
Mar 2, 2006, 11:10 PM
Post #432 of 915
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In reply to: healyje: i totally agree with you, was just wondering what the point of the fancy knot was aside from using up cord and biners. I couldn't see any advantage to it.
kubi said it as well as I could. I just aesthetically like it better and the fact that both power point loops (up and down) load in-line with one another. I alse like that you clip through two strands instead of one at the bottom of the power point. As I said I'd just use one biner instead of two on the equalization loop.
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flyinglow
Mar 2, 2006, 11:12 PM
Post #433 of 915
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my point was, the knot is unnecessary. you don't need to tie it in the first place, just clip a single biner through all the loops. and you save a biner or two in the process(i understand how to tie the knot, what i'm wondering is why)
added:
I'm not trying to start an argument, just asking a question that hasn't been answered in a way i can agree with yet. do what you like. it just seems like work(only a little bit) for no particular reason to me.
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tradklime
Mar 2, 2006, 11:16 PM
Post #434 of 915
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In reply to: my point was, the knot is unnecessary. you don't need to tie it in the first place, just clip a single biner through all the loops. and you save a biner or two in the process(i understand how to tie the knot, what i'm wondering is why) |
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healyje
Mar 2, 2006, 11:25 PM
Post #435 of 915
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In reply to: my point was, the knot is unnecessary. you don't need to tie it in the first place, just clip a single biner through all the loops. and you save a biner or two in the process(i understand how to tie the knot, what i'm wondering is why)
I like that the load biner is captured by the two strands of the power point and is isolated on the other side of the knot from the equalization. It only costs one biner and dog-gone-it, I just love tying that knot....
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charlesjmm
Mar 3, 2006, 1:47 AM
Post #436 of 915
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I think its time to baptize my new anchor design. In doing so I lean towards names that convey intrinsic qualities of the subject or that set it apart from the rest. The qualities that concern us are basically: equalization, redundancy, simplicity, efficiency, etc. Where I believe my design offers something unique is in terms modularity, in other words, it is applicable to 2, 3, 4,
..,n placements (at least theoretically).
So the name of my new rig will be the Modu-lette.
I will update all pertinent posts to reflect this.
CharlesJMM
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hugepedro
Mar 3, 2006, 2:33 AM
Post #437 of 915
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Isn't the modu-lette just a 3 legged sliding-x? I mean, it's a fine rig, but I don't think there's anything new or original about it, is there?
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moose_droppings
Mar 3, 2006, 2:40 AM
Post #438 of 915
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He CJ,
Maybe call it russian roul-lette
just kidding :)
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justthemaid
Mar 3, 2006, 3:24 AM
Post #439 of 915
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In reply to: That knot is really easy to tie, stretch out a cordalette and fold over about 1.5 feet at one end, so that you have two double loops, then tie a figure 8 on a bight on that folded over section.
Thanks for explaining how to tie that knot. I agree that this anchor definitely gets the aesthetic award.
Unfortunately if you blow any piece you get knarly extension. If any cord gets cut you have total failure.
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hemp22
Mar 3, 2006, 3:36 AM
Post #440 of 915
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In reply to: Thanks for explaining how to tie that knot. I agree that this anchor definitely gets the aesthetic award. Unfortunately if you blow any piece you get knarly extension. If any cord gets cut you have total failure.
You can resolve those 2 issues by clove hitching a biner to 2 of the strands (similar to the gordolette method). If you get the right 2 strands, then it limits the extension in the case of a piece blowing, and also in the event of a strand cutting. [This was described by dr_monkey several pages back].
I believe you can also just add a limiter knot to the middle leg above the biners (just like Trango suggests w/ their Alpine Equalizer).
If you do either of those things, then the only way for this rig to get significant extension is if you cut through the upper loop of the knot (the one w/ the 2 biners).
I think I have a picture of that floating around somewhere that I could post.
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jakedatc
Mar 3, 2006, 5:43 AM
Post #441 of 915
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is there any serious draw back to having a overhand as the power point? (double looped in this case) cordalettes are so freaking bulky that i almost never get them to dress nice the first time.. taking up more time.
my attempts at josephs AE rig.. and yes cool knot. i like.. uses up a bunch of cord though.
http://img.photobucket.com/...ocjake/3_3_06002.jpg
once piece fails
http://img.photobucket.com/...ocjake/3_3_06003.jpg
Problem i found is that if any 2 blow.. ur looking at a few feet of extension. meebe i did something wrong.. since i dont think the trango AE fails like that.
it was kinda clunky equalizing back and forth.. either the cord i have is >7mm, still a bit stiff or just the way i had the biners hooked up.
Either way i think i'm going to pick up an AE tomorrow and use either sliding x w/ knots or some version of a -lette that i finally can make work well as the 2nd on the rack.
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healyje
Mar 3, 2006, 6:26 AM
Post #442 of 915
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In reply to: Unfortunately if you blow any piece you get knarly extension. If any cord gets cut you have total failure.
Yep, it's just a straight AE rig, nothing more nothing less, and the Trango unit works exactly the same. If I were going to use this for hauling or a portaledge I'd probably use a double-strand techcord version thus making it with two redundant, independent cords. You can use an overhand, I just don't think it looks as pretty.
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kubi
Mar 3, 2006, 2:59 PM
Post #443 of 915
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In reply to: is there any serious draw back to having a overhand as the power point? (double looped in this case) cordalettes are so freaking bulky that i almost never get them to dress nice the first time.. taking up more time.
Mine wasn't very bulky even with a figure-8. The good thing about this knot, is you only have to tie it once, so you can take the time to make it nice. Also, try making the loop coming out the top shorter, it'll take up less yardage that way.
In reply to: my attempts at josephs AE rig.. and yes cool knot. i like.. uses up a bunch of cord though. Problem i found is that if any 2 blow.. ur looking at a few feet of extension. meebe i did something wrong.. since i dont think the trango AE fails like that.
can you try moving the load-limiting knot closer to the powerpoint?
In reply to: it was kinda clunky equalizing back and forth.. either the cord i have is >7mm, still a bit stiff or just the way i had the biners hooked up.
try using two biners instead of one locker. Mine equalized smooth as silk when I used two biners.
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charlesjmm
Mar 3, 2006, 3:20 PM
Post #444 of 915
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I have been playing with the Equalette and concluded that it is the only design (so far) that satisfactorily handles the failure of (N-1) placements of an anchor with N placements. This virtue deserves very high marks.
I think the Equalette is inviting us to embrace the notion of equalization (meaning uniform load redistribution amongst all placements) with different eyes. I found that, as the power point of the Equalette relocates, the load will generally be equalized amongst 2 placements even if 3 or more exist. So, the question to ask ourselves is: Am I willing to rely on 2 equalized placements at any moment knowing the anchor affords more placements? Lab results apparently provide us an affirmative answer; I hope these results are disclosed soon.
CharlesJMM
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healyje
Mar 3, 2006, 3:22 PM
Post #445 of 915
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Jake, can you add a photo of the quad to your list post. Or can someone post up a shot...
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tradklime
Mar 3, 2006, 4:08 PM
Post #446 of 915
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In reply to: Either way i think i'm going to pick up an AE tomorrow and use either sliding x w/ knots or some version of a -lette that i finally can make work well as the 2nd on the rack.
If you buy a Trango "AE" consider the 3 ft. version. The extension with this set up is acceptable, in my opinion, and you can use the rope or slings to extend to placements if needed. The result will be similar the one of the "firewall" set-ups previously posted in this thread.
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billl7
Mar 3, 2006, 4:13 PM
Post #447 of 915
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In reply to: _So, the question to ask ourselves is: Am I willing to rely on 2 equalized placements at any moment knowing the anchor affords more placements? Lab results apparently provide us an affirmative answer; I hope these results are disclosed soon.
So, in a fully distributed system like your latest, even though each piece initially sees the same load and that per-piece load can never be more than the load from the sharp end of the rope (assuming a centered piece), things can change disasterously if the center piece blows and the outer pieces are widely separated.
Of course, multiplicative forces due to angles is not a new concept. It.s just that this thread presents a new view of it IMHO.
Bill L.
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jakedatc
Mar 3, 2006, 4:20 PM
Post #448 of 915
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Joe.. no idea which one is the quad... post it up and i can add it though
Tradklime thanks for the advice.. i will try to find the 3 ft.. although it may have to come from Trango as i dont think REI carries them :P
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fingertrouble
Mar 3, 2006, 4:34 PM
Post #449 of 915
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charlesjmm, there may be a subtle but worisome flaw in your Modulette. Consider this:
The rig consists of two bights (formed between the center leg and each outer leg) and a loop formed between the two outer legs. The biner clips all three. The loop equalizes tension between the outer legs; the middle leg plays no part, which is why there's little extension if it goes missing.
The two bights distribute tension between the outer legs and the middle leg, but unfortunately, not equally. In fact, their result is twice the tension on the middle leg as on the outer ones. You can see this if you deliberately tie the loop component with slack.
The problem seems to be that the limiter knots don't let the cord slip around the biners at the ends of the outer legs. At a minimum these effects seem to require meticulous construction of the limiter knots (which is what cracklover was getting at), but I don't see any way to do that properly or to test for success.
Other designs may also have the problem of apparent, but not actual, balance of tension (force); the analysis can be tricky.
Why is anyone worried about what happens when 2 out of 3 placements fail? If one placement could hold the load, why was equalization attempted in the first place? A strategy of redirection or redundancy would likely have been more appropriate, and might have prevented failure of the two placements.
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fingertrouble
Mar 3, 2006, 5:01 PM
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It's important to understand the magnitude of fall forces when designing anchors to manage them, but too much digression into calculation details wanders OT.
Therefore, rgold, just some summary points
[*:e7d87e59c3]All these fall force numbers start with the maximum force that the belayer can put on the rope. Figure 1 kN for a hip belay, 1.5 to maybe 2.5 for ordinary belay devices, and around 3 kN for a Münter hitch (mentioned in my book and by John Long early in this thread). Any greater pull will result in rope slip. Pick a belay type and that gives you the peak force on the climber and belayer (and belayer's anchor) in a vertical fall directly on the belay, Factor 2 or Factor 1.
[*:e7d87e59c3]The amount of rope slip will be proportional to the length of the (hard) fall
[*:e7d87e59c3]"body weight" is the maximum force a hanging climber could put on the rope by deliberately jumping around but not actually falling; figure twice the climber's actual weight or 1.5 to 2 kN
[*:e7d87e59c3]IIRC the new Petzl calculator content came from the Italian who contributed the UIAA Journal article on belaying forces, if that's what you were referring to; anyhow I'd expect Petzl read the article. Their model certainly goes beyond conservation of energy and momentum. You could always do the calcs yourself (check Alan Sheehan's work in Technical Rescue; he uses 1.5696 kN for the belay force). The calculations are only tricky in determining the amount of rope slip or the forces in cases where there isn't any. Hooke's Law makes my brain hurt. Sorry, waaay OT. Please PM me your results.
Thanks for your refreshingly unfiltered comments, roy_hinkley_jr. I can sense your desire to contribute constructively. I'm always interested in learning more from alpinists who subscribe to the authority of Freedom of the Hills, so I'd love to hear more from you--I strive to improve my work. But let's take it off line; please PM me with corroborating details, including invalidation of the Petzl fall force calculator that you seem to find troubling.
Craig
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