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fingertrouble
Mar 11, 2006, 1:00 AM
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I posted the gist of this on the original Improved Sliding-X thread, but that has turned into a cesspool, so maybe I can be more constructive here.
This latest round of anchor building discussion came as the result of John Long's query as to what climbers think of the sliding-X and the cordelette. Unfortunately, John didn't distinguish what he meant by cordelette. Did he mean a general purpose, long runner made of accessory cord, or was he referring to a specific means of linking three or four placements with such a cord tied with a big knot at the master point? That confusion bedevils discussions on rc.com.
As I and more recently John have pointed out, the later rig (cordelette with master point knot) can't deliver true equalization. This surprises most climbers. In my book (sorry to mention it, but I offer it as a means of accessing more details instead of coyly posting anonymously) I backed up my claim of no equalization with a numerical example, while John has done better by alluding to tests done at Sterling rope. John implicitly challenged rc.com members to come up with a solution that would provide true equalization under load and he required that it be economic of hardware and have lots of KISS-ability.
There have been many attempted solutions in the sliding-X thread and elsewhere, none successful though the thread is worth reading; the requirements for achieving true equalization under load, especially with KISS, seem somewhat demanding. I thought I would post and illustrate a solution (the only one so far) that meets John Long's criteria for a simple rig that provides true, multidirectional equalization under load using a long accessory cord runner.
The instructions are simple (KISS, remember):
Set up the classic 3-anchor equalizer using a slightly shorter cordelette (call it Craig Short)--except give each bight between the carabiners a half twist before clipping them (just as you would with a sliding-X, thus no need to learn new skills). This achieves a modicum of extension limiting but you still get perfect equalization under load. This is what's shown in the first and second parts of the illustration on page 152 of my book (The Mountaineering Handbook McGraw-Hill 2005).
If you believe what I've written in my book and what John Long has independently measured and posted ad nauseum on rc.com (that so long as there's dynamic rope in the system, shock loading due to extension from a blown placement isn't a big deal) YOU'RE DONE!
If you're irreconcilably paranoid or irrationally technoid and insist upon limiting extension (or have a good, specific reason), the solution is abysmally simple: connect another, preferably slightly longer cordelette (call it John Long) to the existing placement carabiners, tie an overhand knot in the conventional manner, and clip this cordelette's master loops to the main locker so that the result hangs loosely and takes no force unless a placement fails. Presto! No additional carabiners are needed, only one additional piece of soft hardware (another cordelette, which you'll likely want along anyhow), and only one additional knot (an overhand, for a total of one knot in the entire system). As a bonus you also gain some redundancy.
It doesn't get simpler, lighter, or more easily checked. No need for the screwball inventiveness, Newtonian rejectionism, or contrived nit-picking that have laced otherwise informative threads.
http://i2.tinypic.com/r26vt5.jpg
Just a few points:
There's nothing new about the classic, un-named 3-anchor equalizer appearing in the sliding-X thread; you can see it, for example, in the tie-outs for BD's Fitzroy tent. The first time I've seen it published with limiting half twists in the bights is in my book, but who cares.
Anyone who thinks that overlapping cords at the master biner in Craig Short might result in excessive friction should simply test their hypothesis: do some drop tests and look for evidence of sheath melting in that area. You won't find any.
This recipe is readily extrapolated to equalizing four placements, but I personally think that anyone who thinks they must equalize four placements has lost their grip on physical reality.
Don't forget that a cordelette (the long runner made of 6 or 7 mm accessory cord) has uses in addition to equalization and that equalization per se is not a recipe for success with every anchor building problem.
Craig Connally
(Thanks to wkswo for helpful PM comments and suggesting naming the two cordelettes.)
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leezerdgirl
Mar 11, 2006, 1:46 AM
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Thank you. It's simple, makes sense, and I will use it.
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vivalargo
Mar 11, 2006, 2:14 AM
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That looks pretty suave, Craig. The best solutions are usually very simple.
How might this rig (Craigolette??) respond if you tied limiter knots into each arm? Needed? Debatable with good primary placements; but I'm still curious how it would work with said limiter knots.
JL
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seanhabgood
Mar 11, 2006, 2:23 AM
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Hey I tested it I liked it it worked well thanks I will use it. Sean
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healyje
Mar 11, 2006, 2:29 AM
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The "John Long" anchor is going to setup a limiting and not particularly happy relationship between the two rigs in my opinion. You caveat to make the JL rig "slightly" longer overcomes that somewhat, but I still don't much care for the limiting impedence mismatch between the rigs. To some extent this overlay is a no-compromise compromise and not one I'd be inclined to use. I'd much prefer one of the firewalled AE rigs such as RGold's to this configuration. If I got paranoid I still use a single set of extensions, but add a second tandem AE rig to the setup.
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dutyje
Mar 11, 2006, 2:40 AM
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I see a potential problem with this. Forgive me for not being concrete here, as I am just sitting here drinking a beer and am too lazy to anything other than think about it.
The Craig Short, independently, will automatically equalize in the direction of pull. The John Long, independently, is (roughly) equalized in a single direction, but its inclusion is to limit extension.
That's where the problem begins. By limiting extension, you are limiting the radius that the master point is able to achieve as it is pulled away from the originally equalized direction of pull. Specifically, if the load direction shifts to the right, the auto-equalizing Craig Short would need to extend the left-most leg while shortening the right-most leg. However, the John Long would limit the distance that this left-most leg is able to be extended.
Think of how an ellipse is defined, geometrically. You have two focus points, and the edge of the ellipse is defined by points for which the sum of the distance from each of the two focii (sp) is a constant. Of course, the distance from each focus point is different as you move around the ellipse. Then think of how a circle is defined. It is the collection of points that are a constant distance from a given center point.
Now, the non-limiting John Long anchor will behave in a similar manner to the way a circle is drawn. On a three-point anchor, imagine each leg (independently) could move around in a circle around the anchor point, with a radius of the length of that leg. The master point would be restricted to the space contained in the intersection of each of those defined circles.
In order to maintain its proper auto-equalization, the Craig Short would need to be able to move around in some kind of three-point ellipsoid shape whose definition seems to escape my brain at the moment. Anyway, as you get even a small distance from the originally equalized direction of pull, your John Long would begin to limit the travel of the master point, and you would unfortunately likewise lose the benefits of your auto-equalisation.
I could be wrong with all this. I'm suggesting the theory. Like I said, I'm too lazy to go 20 feet over to the counter and grab a pen and paper to fiddle around with the pictures. Maybe some of the other nerds around here can either support or shoot down my theory?
Edit: healyje is saying the same thing I'm saying, but with far fewer words. He also was able to type and submit his much faster than me :)
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moose_droppings
Mar 11, 2006, 2:44 AM
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Wow, 2 anchors instead of one.
Pure genius. Why not post this on the other thread if this is the end all of all holy grails?
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boltdude
Mar 11, 2006, 2:53 AM
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Basic logic:
1) you want equalization because the pro is questionable
2) if the pro is questionable, even with equalization, a piece could potentially blow out
3) if a piece blows out, you get tremendous extension
4) biners can and do break, and this sort of extension to a massive force on the anchor is exactly when they would break.
So, WHY does everyone insist on equalization? Sliding X or this sliding cordalette, 99.9% of trad anchors that people will be using should NEVER be in danger of a piece blowing out.
In a situation that results in a piece blowing (such as a factor 2 on the belay), the rope will likely have been shock loaded already, and will be closer to a static rope than a dynamic (a friend broke 2 biners in a fall this way after a fixed nut broke).
You should NEVER use a sliding X or a sliding cordalette (whatever you want to call it) except when equalizing gear in truly tenuous anchors and in extreme aid placements. If you feel the gear is so poor as to need true equalization, you're already in trouble.
And authors: a fraction of newer trad climbers will set gear poorly, including in anchors. A piece may blow due to incompetence in placement. True equalization GREATLY increases the chance of full anchor failure in such a case.
Greg Barnes, Director, ASCA
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roy_hinkley_jr
Mar 11, 2006, 3:07 AM
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In reply to: The first time I've seen it published with limiting half twists in the bights is in my book, but who cares.
Apparently you do. But you're correct this is nothing new, though it has been published elsewhere.
Greg, there's this thing called "data." Show some.
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healyje
Mar 11, 2006, 3:09 AM
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Greg,
Not sure if you've been following along from the beginning. I think the case for what you are saying has been made for two bolt anchors, but beyond that I believe John is suggestioning approaches that do equalize. The equalette doesn't dynamically and fully equalize like one of the true AE rigs, but it more distributes (equalizes) the load sufficiently to be secure a good load distribution across an anchor set. I don't think anyone here is as set on equalization as it appears (it is fun though), or at least I'm not, but rather an "adequate amount" that provides a good load distribution - something a cordalette appears to fail miserably at beyond to points.
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curt
Mar 11, 2006, 3:55 AM
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dutyje and healyje are, of course, correct. Adding the "John Long" scenario (as shown here) to the "Craig Short" system does exactly the same thing as adding limiter knots to the equalizing system--i.e. it limits the range over which the equalizing system can function.
Curt
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flamer
Mar 11, 2006, 4:07 AM
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In reply to: How might this rig (Craigolette??) respond if you tied limiter knots into each arm?
I've done this for quite awhile. It provide's both EG and limited extension.
The only problem being that it's not as "clean" when all 3 knots are clipped to the same krab.
Now I view this as another tool for the box. I still use the standard single point single knot anchor sometimes, hell i still use a series of cloves on occasion. However when I really NEED perfect EQ AND limited extension I use the "limiter knot" in each "arm" technique.
josh
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moose_droppings
Mar 11, 2006, 4:50 AM
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John
If you tie a limiter knot on more than one arm, it negates EQ when redirected.
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vivalargo
Mar 11, 2006, 4:50 AM
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[quote="boltdude"]Basic logic:
1) you want equalization because the pro is questionable
I WOULD SUGGEST THAT EQUALIZATION IS DESIRED SO YOU HAVE A REDUNDANT AS OPPOSED TO A MERELY BACKED UP ANCHOR--BE THE PRO GOOD, BAD OR OTHERWISE. IN TERMS OF BELAY ANCHORS, REDUNDANT MEANS THE LOADING WILL NEVER FALL ON ONE PIECE OF GEAR--AS LARGELY HAPPENS IN A CORDELETTE WITH UNEQUAL ARMS (OF THAT WE MAY BE SURE).
2) if the pro is questionable, even with equalization, a piece could potentially blow out
ABSOLUTELY TRUE.
3) if a piece blows out, you get tremendous extension
NOT WITH LIMITER KNOTS, AND MOREOVER, RECENT LAB TESTS TOTALLY DISPROVE THE MYTH THAT SHORT EXTENSION CAUSES SO-CALLED "SHOCK LOADING." IT DOES NOT HAPPEN THAT WAY AT ALL.
4) biners can and do break, and this sort of extension to a massive force on the anchor is exactly when they would break.
BINERS ONLY BREAK WHEN A FALL IS ON VIRTUALLY STATIC, HIGH TENSILE STRENGTH CORD DIRECTLY CONNECTING THE CLIMBER TO AN ANCHOR--AS IN THE RECENT TESTS DONE BY ROCK AND ICE FEATURING A LEADER CLIPPING OFF A BELAY ANCHOR WITH A SPECTRA DAISY CHAIN, THEN FALLING A FEW FEET DIRECTLY ONTO THE ANCHOR. WHEN A DYNAMIC CLIMBING ROPE IS FED THROUGH A BELAY DEVICE (WHICH ALWAYS RESULTS IN ROPE SLIP AT THE DEVICE) AND A FALL IS SUSTAINED, THERE IS ENOUGH GIVE AND FLEX IN THE SYSTEM THAT BINERS DO NOT BREAK FROM THE IMPACT. IN SHORT, THE KIND OF EXTENSION POSSIBLE WITH A RIGGING SYSTEM USING LIMITER KNOTS WILL NOT CAUSE SHOCK LOADING IN A SYSTEM FEATURING A DYNAMIC CLIMBING ROPE AND A BELAY DEVICE.
So, WHY does everyone insist on equalization? Sliding X or this sliding cordalette, 99.9% of trad anchors that people will be using should NEVER be in danger of a piece blowing out.
NOR WILL THEY BE IN DANGER OF EVER BEING IMPACTED DIRECTLY AS HAPPENS IN A WORST CASE SCENARIO FACTOR 2 FALL. THE CONCERNS FOR AN EQUALIZED ANCHOR AND A RELIABLE RIGGING SYSTEM TO ACHIEVE SAME ARE ONLY VALUABLE IN THE WORST CAST SCENARIO--BUT BROTHER, YOU'LL MOST ASSUREDLY WANT THEM SHOULD YOU EVER EXPERIENCE ONE. THANKFULLY, FEW OF US EVER WILL--THE VERY REASON THE CORDELETTE HAS LARGELY "WORKED" SO FAR.
In a situation that results in a piece blowing (such as a factor 2 on the belay), the rope will likely have been shock loaded already, and will be closer to a static rope than a dynamic (a friend broke 2 biners in a fall this way after a fixed nut broke).
A DYNAMIC CLIMBING ROPE WILL NOT SHOCK LOAD IN THIS WAY, NOR DOES IT TURN INTO A DYNAMIC ROPE ONCE WEIGHTED--OR THAT'S WHAT THE RECENT STERLING TESTS SHOWED US. YOU'D LIKELY HAVE TO LOOK AT OTHER FACTORS THAT CAUSED TWO BINERS TO BREAK IN SUCH A FALL.
You should NEVER use a sliding X or a sliding cordalette (whatever you want to call it) except when equalizing gear in truly tenuous anchors and in extreme aid placements.
I CAN ONLY MAKE SENSE OUT OF THIS STATEMENT BASED ON A BELIEF THAT EXTENSION IN A SLIDING X OR EQUALETTE WILL CAUSE SHOCIK LOADING. SINCE THIS HAS RECENTLY BEEN DISPROVED (PROVIDING LIMITER KNOTS ARE USED), THIS STATEMENT NEEDS TO BE RETHUNK.
If you feel the gear is so poor as to need true equalization, you're already in trouble.
TWO IS BETTER THAN ONE IS THE STRATEGY USED BY MOST COMPETANT TRAD CLIMBERS--THAT'S WHY THERE ARE TWO BOLTS ON HANGING BELAYS ON EL CAP--NOT JUST ONE.
And authors: a fraction of newer trad climbers will set gear poorly, including in anchors. A piece may blow due to incompetence in placement. True equalization GREATLY increases the chance of full anchor failure in such a case.
FOR STARTERS, I ASSUME THAT ALL NEW TRAD CLIMBER WILL PLACE SUSPECT GEAR. AGAIN, I SUSPECT YOUR FEAR HERE IS THAT AN EQUALIZED SYSTEM WILL CAUSE EXTENSION THAT WILL CAUSE SHOCK LOADING THE WILL "GREATLY INCREASE THE CHANCE OF ANCHOR FAILURE." THAT'S WHY THE RECENT DROP TESTS DONE BY STERLING ROPES WAS IMPORTANT--BECAUSE THEY SHOWED THIS DID NOT HAPPEN.
MY SUSPECION HERE IS THAT YOU HAVE AN IDEA FIXE WITH THE CORDELETTE, WHICH YOU STILL INSIST IS THE BEST SYSTEM BECAUSE IT LIMITS EXTENSION. I WOULD ENCOURAGE YOU TO READ RICH GOLDSTONE'S COMMENTS AND MATHMATICAL WORK UPS ON "CASCADE ANCHOR FAILURE." I SUSPECT THAT WILL MAKE THIS ALL CLEAR.
JL
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kobaz
Mar 11, 2006, 5:36 AM
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Can you please not type in all caps? It's quite troublesome to read. I like the anchor debate, carry on.
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curt
Mar 11, 2006, 5:37 AM
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In reply to: Can you please not type in all caps? It's quite troublesome to read. I like the anchor debate, carry on.
STFU.
Curt
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bhilden
Mar 11, 2006, 5:53 AM
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I don't want to put words in Greg Barnes' mouth, but I think what he is saying is that in a very large percentage of climbing a competent climber with good equipment doesn't have to worry about setting up a belay with the absolute best method of equalization. Certainly, if you can't place pro very well or you can place pro but the rock won't let you get good stuff in, then you probably need to worry about the absolute best method of equalization.
Airline pilots have a thing they call "situational awareness". I think this also applies to climbing. A competent climber knows when it is time to worry and when it is not. I don't think this makes the current discussion moot. It just means that it isn't as significant to the majority of the situations faced in building anchors. Get good gear in, make sure it is reasonably equalized and climb on.
Bruce
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harris
Mar 11, 2006, 6:11 AM
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There is one aspect of comparison of both anchor methods that I have not seen discussed. that is the result of failure of the webbing or cord used to tie the anchor points together.
All discussion so far has been about the results of a failure of an anchor point. The pros and cons of each method in that regard are clear:
The "Craig Short" method, while providing perfect equalization, and allowing for maintaining equalization with a change in direction of pull on the anchor, will shock load in the event of a failure of an anchor point.
There may be disagreement as to the seriousness of the shock load, considering the mitigating value of the dynamic rope. Generally, I would think that the shock load is best avoided.
The "John Long" method, if carefully constructed, will provide near perfect equalization in one direction of pull, and that is likely all that is needed. If an anchor point fails, there is no movement of the anchor and no shock load, but the equalization changes to load heavier on the remaining anchor point that is most in line with the direction of pull.
There is a critical difference between these two anchor methods, however, in the event of failure of the webbing or cord used to create the anchor.
In the "craig Short" method, failure of the cordellette, at any point, causes total failure of the anchor, regardless of how many anchor points were tied together. The cordellette, or webbing, will no longer be a loop, and the weighted rope will pull the broken cord out of all anchor points.
If limiting knots were tied between the main tie-in point and each anchor point, that could avoid total anchor failure, but, again, limits the amount of sliding equalization available for changes in the direction of pull on the anchor, which is the reason for using that method in the first place.
On the other hand, it is not likely that a large amount of directional change, if any, is necessary. But creating the sliding equalization, and then limiting it with internal knots, is cumbersome, time consuming, and somewhat self-defeating.
In the "John Long" method, a break in the cord anywhere above the knot that creates the tie-in point will have exactly the same effect as the failure of an anchor point: simply the loss of the anchor point that was tied into the broken section of cord. The remaining anchor points are still tied by independent loops.
A break below the knot would have no effect, as there are several redundant loops created below the knot.
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vivalargo
Mar 11, 2006, 6:16 AM
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In reply to: Airline pilots have a thing they call "situational awareness". I think this also applies to climbing. A competent climber knows when it is time to worry and when it is not. I don't think this makes the current discussion moot. It just means that it isn't as significant to the majority of the situations faced in building anchors. Bruce
A terifically equalized anchor only matters in a very, very small fraction of situations--like one in a million, maybe less. The problem is we often don't know, for sure, when those situations are. So the only thing we can do is guard against the very long odds without going crazy with the thing or wasting time. As a person who helped invent speed climbing big walls, I'm the last person who wants to fiddle around with needless rope shenanagans. I won't, in fact.
I've said all along that the only viable alternative to a traditional cordelette is something that takes the same time and ease to rig, but renders better results in those super rare situations where it might matter. If you can find such a system, there's little reason not to use it.
JL
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bhilden
Mar 11, 2006, 6:32 AM
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In reply to: In reply to: Airline pilots have a thing they call "situational awareness". I think this also applies to climbing. A competent climber knows when it is time to worry and when it is not. I don't think this makes the current discussion moot. It just means that it isn't as significant to the majority of the situations faced in building anchors. Bruce A terifically equalized anchor only matters in a very, very small fraction of situations--like one in a million, maybe less. The problem is we often don't know, for sure, when those situations are. So the only thing we can do is guard against the very long odds without going crazy with the thing or wasting time. As a person who helped invent speed climbing big walls, I'm the last person who wants to fiddle around with needless rope shenanagans. I won't, in fact. I've said all along that the only viable alternative to a traditional cordelette is something that takes the same time and ease to rig, but renders better results in those super rare situations where it might matter. If you can find such a system, there's little reason not to use it. JL
I agree 100%. I am just trying to keep from getting stuck behind a slow party because they are being totally anal about constructing the very best, most optimal, anchor when they can get 99% of the same anchor with 10% of the effort.
Bruce
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hemp22
Mar 11, 2006, 6:34 AM
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harris, a couple points:
The "john long" cordalette setup does NOT perfectly equalize even in 1 direction according to JL's recent drop tests. The shortest leg of the cordalette takes almost all of the force of the fall. see sliding X thread for more info on this.
For the "craig short" system, yes, if the cord is cut, the whole anchor would fail. But when people mention adding limiting knots to that particular system, they're usually not talking about adding knots to all 3 legs of a 3-piece anchor. in the other thread there are also lots of pics and info on ways to make an equalizing 3-piece system also have limited extension. but, with all those systems, and even Craig's combined anchor suggesting (the "craig short" + "john long") the more you limit the extension, the less range you get for direction of pull that still allows equalization.
As for the simplicity of Craig's combined anchor suggestion, I don't see it having much more range of equalization that a lot of other systems that also limit extension, and when it comes to the complexity of a system, I'd rather just have to add 1 or 2 more biners to a single piece of cordalette, than have to carry up a whole second cordalette to set that system up.
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blondgecko
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Mar 11, 2006, 7:46 AM
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In reply to: I posted the gist of this on the original Improved Sliding-X thread, but that has turned into a cesspool, so maybe I can be more constructive here.
Abrasive, not particularly inventive, and breathtakingly arrogant. A big steaming pile of poo from me.
The other thread put forward a number of rigs that would use less material, be faster to set up, and are no more complex than this. To put yours forward as the only usable solution is incredibly intellectually dishonest.
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jonqdoe
Mar 11, 2006, 8:35 AM
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In reply to: John If you tie a limiter knot on more than one arm, it negates EQ when redirected.
Maybe someone suggested this in the other thread, I stopped following it at about page 34, but here goes:
Since we're already carrying two cordalettes, instead of having one as a John Long and the other a Craig Short (the problems with that have been pointed out by many), why not just use two "Craig Shorts"? You can limit the extension in this setup by putting one limiting knot on each short, only on different pieces. In other words, if your pieces are numbered 1,2, and 3, and number 2 is in the middle, on the first short tie a limiting knot on the strand to piece 1, on the 2nd short tie the limiting knot on the strand to piece 3. Then you have something simple and redundant that *should* equalize, and won't extend past your knots. I'll draw a diagram if that's not clear...
My concern with this is the equalization. Having two shorts going to one biner will require a lot of cord sliding past itself in order to equalize, and I'm not sure how realistic that is. I don't have two cords so I can't try it, but it was just something I thought I'd throw out there.
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kricir
Mar 11, 2006, 10:17 AM
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Id like to hear any thoughts on the “3 loop sliding figure 8 on a bight thing”. I don’t know the real name for this knot, so I will just refer to it as the sliding 8. Im sure you know of what I speak, you tie a figure 8 on a bight with a small loop on one end and the rest of the cord on the other. You then take the long end and pass it through the hole from were it came, only on the other side of the knot. This produces 3 loops. This seems to me to provide “perfect equalization” although it requires some adjusting if direction changes. If any pieces pull, or if the cord is cut above the knot, It usually locks up, and will not extent wildly like a sliding x. I see this knot to be a good compromise between the two.
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healyje
Mar 11, 2006, 10:52 AM
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I would second hemp's comments to harris and add that folks really need to read the sliding X thread start to finish before jumping in here otherwise we are going to just be repeating most of that conversation unnecessarily.
------------------------------
The sliding X page where Jake gathered all the photos - A good link to use as a signature in all posts in either thread of these threads.
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