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flyinglow
Feb 23, 2006, 2:00 PM
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In reply to: In reply to: downside to the single biner setup, if you blow two pieces on a three piece anchor, it extends a lot. I'm leaning back towards the gordolette now that i've spent a few more minutes playing with it. I can't see how one biner vs. three makes any difference in the length of the extension in the case of the failure of N-1 anchors in the setup. In reply to: I was playing with a fully equalizing setup, and not exactly what charles has pictured. it looks like charles' would load heavier on the center piece/pieces than on the outer legs.. The principal weakness of the multiple sliding-X design is that once you get more than three anchor points you can't easily equalize across the multiple X units anymore. At that point it starts acting more like a cordalette. In reply to: what i was trying to go for was more like a sliding x but with 3 equal legs. it would equalize forces nicely, but is a royal pain in the A55 to stop it from extending. back to the drawing board. Someone early one was talking about a three point sliding-X but I don't think they posted up any pictures.
sorry about lack of clarity, the single biner doesn't affect extension, it was the setup i was using, which was fully equalizing.
setup as follows:
loop cordelette three times around your hand creating three consecutive loops of equal size.
clip master point biner through all three.(where your hand holds the three loops)
clip one loop to each piece of pro.
problem: when moved away from center the piece which the master point is moved away from gets double force compared to the other two if limiter knots are tied. (this is what i was trying to avoid in the first place)
w/o limiter knots, the cord isn't redundant, and it's badly extending unless your pieces are really close to each other.(hence a really short cordelette)
on a tripled x, the limiter knots keep it from equalizing over a range of movement. two cloves on a biner won't work in place of a knot,(opposite the case of the gordolette), as the limiter knots are directly loaded in the case of a failure. you could theoretically use a piece of sling or prusik, but it adds a lot of complexity and uglyness to the system.
i thnk gordo's is the only 3 piece anchor that's fully equalizing and redundant that i've seen so far in this thread, and it's pretty quick/simple to set up
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healyje
Feb 23, 2006, 2:14 PM
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Gordo's setup does equalize, but limited by the biners, so I wouldn't call it "fully equalizing".
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flyinglow
Feb 23, 2006, 3:14 PM
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maybe not 100%, healyje, but it had a much better range than the other setups i've tried, and within it's operating range seems well balanced. it seemed to offer the best range of equalization/extension limiting ratio.
Equalization range could be imroved by the addition of quickdraws instead of single biners for limiting. At the cost of increasing extension and complexity. I think you have to weigh the benefits of equalization range against extension and the falls you're likely to see in a particular instance. I can't figure any way to create a non-extending anchor that will fully equalize any direction of pull. i think we may be stuck with a trade-off between equalization range and extension.
i've been playing primarily with 3 piece anchors b/c they seem the hardest to eq. a 4 piece is pretty easy to do with 2 sliding x's, equalized with another.
if you can't get 3-4 good pieces to make an anchor you'll trust, things are gonna get complicated pretty quick.
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billl7
Feb 23, 2006, 3:35 PM
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In reply to: Gordo's setup does equalize, but limited by the biners, so I wouldn't call it "fully equalizing".
The duo glide appears to also not be fully equalizing but do correct me if I am wrong. I mean, the legs down to the limiter knots are static in length, yes?
Bill
P.S. I'm not doing tit-for-tat here at all. Just trying to clarify things in my mind.
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healyje
Feb 23, 2006, 4:18 PM
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I think much of the discussion and design fanagling is all about the inital question John raised about the attempt to pursue the fairly mutually exclusive goals of equalization and extension (and redundancy). They work against one another, so I think any solution will always be a matter of trade-offs and compromise. All the various designs boil down to expressions of changing the values of the variables involved with that essential compromise.
The pure sliding-X and AE rigs represent a high value setting for equalization where as cordalettes and other statically limited designs represent a high value setting for extension. I think the designs John and his crew have come up with in this testing - the Equalette and quad - are attempts to moderate both those values settings and provide the redundancy lacking in highly equalized rigs.
Those designs essentially use two sets of static length legs and adequately equalize across those two sets and within each set. In the balance of all the positives and all the negatives I'm fairly sold on the Equalette/Quad direction compared to all the other designs we've played around with here so far. It doesn't provide "the best" of anything, but does provide "enough" of everything. This whole discussion is pretty well summed up by:
You can't always get what you want
You can't always get what you want
You can't always get what you want
But if you try sometimes you just might find
You just might find
You get what you need
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flyinglow
Feb 23, 2006, 4:52 PM
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all right,
equalette=duo-glide, I understand that now, doesn't seem to equalize very well though.
where does the quad fit in?
is it the same thing by yet another name or is it something else?
for 3 pieces of pro i still like the gordolette, it seems to offer a good amount of redundancy and equalization.
i was also able to rig a gordolette with 4 pieces and 3 limiting biners, but you don't get a great range of true equalizaton before it starts to pull on one or two pieces harder (less range and more extension, confusing to rig)
Edited: i opened my mouth too soon and am now eating my words, bold was changed.
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dr_monkey
Feb 23, 2006, 5:57 PM
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I have been trying all of these anchors out and read every page of this thread and I must say it is one of the best ones I have read (and contributed a little bit to.) My thesis is suffering at the moment and I need to go work on it but I need to get this out there so I can think about something else. I'm a little excited because I think that I might have hit on a good idea. Any input would be greatly appreciated.
Here is the problem that I have had with most of these set-ups so far. They work great in linear applications but not when you have a truly funky anchor where you REALLY need to equalize. I often climb where an anchor does look a bit like a shotgun went off. Due to rock quality issues I need to span an anchor over different features (Thanks for the great comments on stance Healyj, sometimes stance is half the anchor :wink: ). I also don't like carrying a bunch of heavy stuff (except for the heavy stuff I am already used to carrying) like a bunch of locking biners.
Sorry for the long intro, please read on.
I thought "why not isolate the functions of the rigging system, somehow separating the equalization and extension problems?" This is what I finally came up with. Sorry the pictures are cluttered, but I should be at school not playing with gear.
http://i42.photobucket.com/...erdavid/DSCN0082.jpg
The cordelette at the top of the anchor both decreases the angles and limits extension. No, I am not worried about the single strands running to a piece. If you are then the cordelette can be rigged differently, or even seperate slings can be used at each piece, it still works. In this picture the pieces are linear, but it still works when one or more are moved out of line.
http://i42.photobucket.com/...erdavid/DSCN0083.jpg
The bottom part is a large loop of the rope tied with a butterfly. The loop is made at a distance from the tie-in to the harness dictated by where you want to be located. Leave enough room to attach to the locker with a clove plus slack between the clove hitch and the butterfly knot. The slack is required to keep your weight of the knot, which limits the equalization. The rope from the other side of the butterfly goes to the other climber via the belay device. Use the loop to create a mini sliding-x. I chose non-lockers for this because 1) they are backed up, and 2) I actually have enough with me on a climb. This is the part of the system that equalizes. Since the loop is so small and made of dynamic rope the "shock loading" from extension here is minimal.
Every system has advantages and disadvantages, therefore the application of any system in a given situation must be weighed. Here is what I can see, please feel free to add to this list.
Advantages; Equalizes in 3 dimensions, limits extension, minimal extra gear, utilizes dynamic properties of the rope, lead rope is strong.
Disadvantages; If the loop of rope is cut the whole thing goes, but isn't that always the case, if the rope cuts your generally screwed? And the loop's exposure is minimal considering it's size and location near your body. The bigger the loop the greater the; range of motion is, the potential extension is, and the exposure to cutting is. Escaping the belay is not easy if you want to stay tied into the end of the rope and take it with you. Also this rig is still complicated and time consuming, but not any more than many other rigs, and less than some.
There it is, give it a try and see if there are any other considerations that I am missing. Sorry if all isn't clear. I am off to school, but I will check back later to see if there is any need for clarification or better photos.
Cheers,
DRS
Edited; Sorry about photo size and orientation, I will try to fix it later. (Fixed)
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vivalargo
Feb 23, 2006, 6:48 PM
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[quote="flyinglow"]all right, equalette=duo-glide, I understand that now, doesn't seem to equalize very well though.
Huh? The reason we are pushing the equalette is not because it is something we are hung up on but because in the actual drops tests it equalized remarkably well. And since extension of a few inches is not an issue, and because the equalette can sustain off axis loading, it's looking the best of the lot so far in terms of field testing. Believe me, I have no preference as to any rigging system save that it is simple, uses no extra gear and actually works as advertised.
JL
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cracklover
Feb 23, 2006, 7:30 PM
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In reply to: Believe me, I have no preference as to any rigging system save that it is simple, uses no extra gear and actually works as advertised. JL
Perhaps the system you're using is not the same one I've seen, but as advertised, it doesn't seem able to equalize well over more than two pieces.
GO
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healyje
Feb 23, 2006, 7:43 PM
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Cracklover, I suspect you're doing something peculiar or not setting the equalette up right. It works as advertised when I've put it up. Look at the diagram on page #6 again and John's iinstructions at the bottom of that same page.
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charlesjmm
Feb 23, 2006, 7:48 PM
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http://i42.photobucket.com/...erdavid/DSCN0082.jpg
Dr_Monkey, your idea looks interesting for its simplicity. The observation I have is that the middle legs bear twice as much load as the outer legs, therefore uniform equalization is not obtained. You might fix this by extending the arm to the outer legs to meet at the bottom biner so you have two strands per leg.
CJMM
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pastprime
Feb 23, 2006, 7:52 PM
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Apologies in advance for my feeble mindedness, but I've followed this thread as it has developed, and still don't know which anchor layout is being called equalette/duoglide. I just went back through the whole thing fairly rapidly, and still didn't pick it up. Moosolette, Gordolette, Alpine equalizer, I got; but I still don't know what layout is being referred to as an equalette or duoglide. Would someone please be kind enough to get me on the bus with everyone else? I'm not asking for explanations, I'm quite clear on that; I just don't know which is being called by that name.
Thank you in advance.
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healyje
Feb 23, 2006, 7:58 PM
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Dr_Monkey,
The logic of separating the equalization and extension is a reasonable tactic but one that does not and I think can not succeed in the end. By introducing a hard demarc or firewall between the two functions you create new and unique problems. This design provides scant (lower) equalization before quickly loading a single outside (upper) strand and collapsing all the other strands. Again, the intent and method is on target, but I think the hard demarc in the system ultimately shows the futility of a "separation of functions" approach. Good go though!!!
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flyinglow
Feb 23, 2006, 8:22 PM
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vivalargo: maybe there's something i'm missing on the setup of the equalette. The way i had it, it will equalize great for a straight down(or whatever axis) pull, but is not self aligning/equalizing(off axis pulls load considerably more or less on different pieces) When i pulled a little to one side on the equalette(as i understand it) one or more of the legs went totally slack(no load at all!)
the problem of off axis loading may not be as big a deal as we're making it out to be, i don't know
dr monkey: your system looks nice, but has the same problem as charlesjmm, the outer 2 pieces are only taking half as much load as the other 2.
add a 4th runner connecting the outer 2 pieces with one more biner and you might have a winner :)
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healyje
Feb 23, 2006, 8:28 PM
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Equalette / Dou Glide :
Look at the healyje diagram on page #6 again and John's iinstructions at the bottom of that same page.
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healyje
Feb 23, 2006, 8:37 PM
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John or RGold (or others),
I've read several statements now by flyinglow, charlesjmm, and others to the effect that "middle leg carries twice the load than the outer ones". I'm not an engineer and looking at the photos I'm really not getting that statement. It doesn't look to be true on the surface so I'm asking what you two or others think about these statements? Are they really true?
Clueless in PDX...
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charlesjmm
Feb 23, 2006, 9:03 PM
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I have been thinking on establishing a comprehensive set of criterion in order to evaluate the quality of all the proposed anchor ideas. If adequate definitions (meaning measurable) for each parameter are established, an evaluation matrix could be obtained and all this great collective effort could be somehow summarized. Thereafter, maybe the most promising designs could earn a trip to the lab test to obtain definite results......
So far I have thought of the following :
1- Proper equalization
1a - In normal operation (no failure)
1b - When failure occurs, will the anchor maintain proper equalization in the resulting configuration? :
1bi -When any placement fails
1bii. When more than 1 placement fails
1biii - When the cordelette is cut at any point
2) Range of equalization (degrees?)
3) Limited Extension during failure
4) Redundancy
5) Minimum gear requirements
6) Simplicity
7) Rigging time
8) Modularity (applicable to 2,3,4, ….. n placements)
9) Potential biner crossloading
10) Suitable for horizontal placements
11) Suitable for vertical placements
12) Suitable for different axis placements
13) Suitable for ice anchors
Some of these parameters may overlap and could be grouped as one.
Any comments/ideas regarding definitions / value scales are welcomed.
CJMM
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billl7
Feb 23, 2006, 9:07 PM
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In reply to: John or RGold (or others), I've read several statements now by flyinglow, charlesjmm, and others to the effect that "middle leg carries twice the load than the outer ones". I'm not an engineer and looking at the photos I'm really not getting that statement. It doesn't look to be true on the surface so I'm asking what you two or others think about these statements? Are they really true? Clueless in PDX...
Now make a similar anchor with four strands going to some pieces and two to others and the pieces are not equally loaded.
Bill
Edit: However, I have not thouroughly thought through the interplay of limiter knots. Still, I think the above holds if it can be said that at any given point, a single strand is under the same tension as elsewhere.
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landgolier
Feb 23, 2006, 9:25 PM
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In reply to: John or RGold (or others), I've read several statements now by flyinglow, charlesjmm, and others to the effect that "middle leg carries twice the load than the outer ones". I'm not an engineer and looking at the photos I'm really not getting that statement. It doesn't look to be true on the surface so I'm asking what you two or others think about these statements? Are they really true? Clueless in PDX...
I'll let the real engineers put in the details, but in simple terms it's the same phenomenon as why you shouldn't climb doubles-style on singles (or if you do, you need to make sure you can't factor 2 onto both lines), and you should never ever ever run singles or doubles like twins. More strands = less extension = more force. I always advocate playing with rubber bands for this stuff - get 4 and put two around your middle finger and one each on the index and ring. Pull on your "power point" and you will see that there is more force on your middle finger. If the effect isn't noticeable, put about 5 on your middle finger and you will feel it - the other two "pieces" almost might as well not be there for all the force they take.
[eyes webolette suspiciously]
Also, as others noted, it is true that the equalette only evenly loads the pieces when pulled from a certain direction, it's just way more capable of finding that direction by itself than you are when tying off a cordalette. Pull off to one side, though, and it's just a sliding x to two pieces with backups, with no possibility for the clutch effect of the normal sliding X. I'm happy with that.
Other notes from home experiements: dress your overhands so that the length of the strands between the knots is really right on. You don't need the monster swallows-four-loops-of-7mil-a-reverso-and-a-lead-line-clove biner for the power point, but you do have to have 2 biners, and they do lay together a little bit weird. Seems to be OK clipping both channels of a B-52, since the device is designed to run that way for belaying doubles/2 seconds, but you'd have to go two biners into one (sort of trixial loading, ugh) or clip in two short slings or something to reel in seconds on a grigri, gigi, or anything else that only takes a single attachment point. Not too bad, but you have to add in that mufti to make it work. With a reverso I guess you could clip it to both biners, but again, loading on more than 2 points gives me that puckery feeling.
I love that we're all sitting around in various places around the country lacing up 4 point anchors on our bannister poles and stuff.
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dr_monkey
Feb 23, 2006, 9:30 PM
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I think everyone is right about the middle legs bearing double weight. The bottom mini-x splits the load 3 ways, each 3rd of the load is distributed to 2 strands of the cord, so each strand takes 1/6th the load after the limiter knots. Since the two center pieces carry 2 strands each they each carry 1/3 the load and the remaining 2 outside pieces take 1/6th of the load each. Not sure if that was a clear description but the math ((2x1/6) + (2x1/3)) works for me, so...
The configuration of the cordelette is not fixed. I am not at home at the moment (I'm "working" on my thesis :wink: ) so I can't play with it, but I think that you can change the cordelette and it still works. I'll try it out later and post pics.
healyje said
In reply to: This design provides scant (lower) equalization before quickly loading a single outside (upper) strand and collapsing all the other strands. Again, the intent and method is on target, but I think the hard demarc in the system ultimately shows the futility of a "separation of functions"
You are right, I think the mutual exclusivity of extension limitation and equalization wins out whether there is a separation or not. The amount of movement is limited, better than a tied off cordelette, but not as good as the duo-glide. It does seem to work better with a non-linear set of pieces though.
So I guess my question now is how much range of motion is actually needed, or even possible. The geometry of both the rigging and the rock limit the direction a force will be applied. Ultimately the force is mostly downward when we are talking about a leader fall through the belayer onto the anchor (usually, but all sorts of exceptions apply.)
I have been using a traditional cordelette for most complex anchors for awhile so I don't need to move around a whole lot while belaying. What I am looking for is good distribution of the load on the pieces, or just enough equalization to negate the "short leg" effect. If I needed to dance around the belay like Mal, then I think that the alpine equalizer would be a good bet.
[sarcasm] Having said all that, of course I like MY way the best and I am going to defend it till my death. [/sarcasm] Really, I welcome criticism and will try not to get to defensive. I am fully aware that this is just another untested way to equalize an anchor.
The safest bet is probably the the one that is actually being tested, not all these funky jobs that we have been brainstorming her,
Cheers,
DRS
Edited for my poor spelling and grammar.
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flyinglow
Feb 23, 2006, 9:42 PM
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is this what people are referring to as an equalette?
http://i42.photobucket.com/...low/straightpull.jpg
if so, my problem is: if you pull off to one side, 2 arms go slack:
http://i42.photobucket.com/...yinglow/sidepull.jpg
maybe somebody can correct me, or clarify things better.
healyje: on the force distribution myself and others have talked about: think of it like a 3-1 pulley system (like you use for hauling), the center piece on the anchor would be your anchor with the rope going through it. and back down to the load
the main anchor point is the load.
the outer piece is the part you pull on.
the outer piece(what you'd pull on in a pulley system) only sees 1/3 of the total force applied to the anchor
the way i see it, the best case is if the limiter knots (and single center biner)keep the anchor point from acting like a pulley, in which case the only problem is the stretch(modulus) of the rope which is twice as stiff with 2 strands.
worst case is with no limiter knots where you basically have a 3-1 pulley set up, and as such 1/3 of the force going to the outer piece/s and 2/3 of the force applied to the inner piece/s.
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charlesjmm
Feb 23, 2006, 9:50 PM
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Healyje, maybe a graphic will help :
http://i49.photobucket.com/...rlosjmm/IMG_3114.jpg
For this system to be in equilibrium, all downward forces must be opposed by equivalent upward forces. The middle anchor bears extra duty since it must hold an additional leg the other anchors don’t have.
Hope that helps.
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cracklover
Feb 23, 2006, 10:00 PM
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Yup, that's what I built, and it only equalizes two pieces at a time.
See flyinglow's pic for an illustration of what happens.
GO
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healyje
Feb 23, 2006, 10:02 PM
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Thanks guys, that does help. Again, once I'm in programming mode little else makes sense and my abilities to follow along or envision some of this goes out the window. Somehow I had it in my mind that the load would be (load / anchors) almost regardless of the rig.
I can see in the chart how what you are saying would work relative to a two knotted powerpoint rig. So my next question would be is it the same deal on single powerpoint AE rigs with sliding versus fixed legs. Something tells me you're all going to say yes.
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healyje
Feb 23, 2006, 10:04 PM
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Cracklover, that's not what John's testing is revealing - they show a cordalette not equalizing well and the equallete equalizing extremely well. It equalized well when I tried it.
====================================
Edit: Ah, I see we are running afoul of verbage and definition here. "Equalization" is a bit of a "loaded" term in this discussion and being used interchangeably for two different meanings.
1) Spreading the load across anchors "evenly" (now I'm cautious about that!)
2) The ability for the powerpoint to move or "slide" side-to-side (in the case of a horizontal spread of anchors)
These are clearly not the same thing. I'm not sure what term to use for #2, but I believe the definition associated with #1 is the operative one in the context John is using the term. He means that in a straight downward drop test all the individual strands equalize against the load quite well.
In the case of the Equalette you are sacrificing nearly all of the "sliding powerpoint" capability in exchancge for reducndancy and equalization [of]. It shares the reduction of that capability with cordalettes.
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