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asdf
Jan 5, 2007, 5:44 PM
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Just wondering if anyone else out there is worried that the equalette hangs all the safety on just two strands of cordalette? I know that nylon 7mm can hold great amounts of force when tied in a prussik loop but does the sliding portion of the equallette count as a loop? In addition, if you leave your equallette tied then the same portion of the cord will always see the wear and tear weakening the most vital area.
I was thinking about making a equallette without tying the ends together but simply tying the ends into the figure eight knots. This would add a third strand at the power point. Anyone see any concerns with this idea?
triple over at the sliding section
tie loose ends into the figure 8's
now you have three strands
(This post was edited by asdf on Jan 5, 2007, 6:07 PM)
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devils_advocate
Jan 5, 2007, 6:02 PM
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Are you talking about the space inbetween the two limiter knots? Because obviously the anchor side is built off of more than two strands.
The single rope sliding biner concerned me at first too. I figured you could take a normal sling, or 12" loop of cordage and lay it across where the sliding portion will be. Then tie the limiter knots to include that section of cordage/webbing. Now you'll have 4 strands between the knots and you can pick two for your main powerpoint.
...then I convinced myself that the single strand powerpoint with a backup locker on the other strand was sufficient and I stopped worrying about it.
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asdf
Jan 5, 2007, 6:10 PM
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I added some photos to make things more clear. I am sure many of you will think I am paranoid, but there is the possibility for the entire force of a fall to land on just one strand of the cordalette. If that one strand fails because the force was too great, what is the chance of having the other strand hold?
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billl7
Jan 5, 2007, 7:16 PM
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For the reason you point out (less strands at the power point), I am more picky about what cord I will use in the standard equalette: 7mm nylon with a rated strength of 11 kn instead of, say, 6 mm and/or cord of a lower strength rating. So for one locker on one strand of the equalette, that's 22 kn; okay, there are losses to deduct for bending around the biner.
Now compare that to 2 strands going through a limiter knot. This is also 22 kn but less the losses due to the knot.
It's not much of an argument but: if one is comfortable with the limiter knots then one ought to be comfortable with a biner on one strand. That said, I do try to make the strands between the limiter knots the same length so both take some of the load.
And I do regularly replace my anchor cord.
Bill L
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billl7
Jan 5, 2007, 7:53 PM
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deleted - see vivalargo's answer next.
(This post was edited by billl7 on Jan 6, 2007, 12:39 AM)
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vivalargo
Jan 6, 2007, 12:26 AM
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Just wondering if anyone else out there is worried that the equalette hangs all the safety on just two strands of cordalette?
-------------
I suspect you're talking about if the belay anchor gets fallen on directly--as in a hight Factor fall. The whole point of the saftey system is to safegard against this ever happening, and as pointed out in the new boot, the top piece in the chain always bears the most loading--and this should never be the belay anchor. On top rope of belaying the 2nd set ups, the loading is never significant to worry about breaking the rigging rope (providing it's in decent shape). When the Equalette was drop tested it perfomed fine with the two strands. If you're scared, go with the quad, which gives you 4 strands at the power point.
JL
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asdf
Jan 6, 2007, 1:55 AM
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Yeah, it is a factor 2 fall I am worried about. I realize that you should not plan on factor 2 falls hence the "jesus nut," but they do happen. It seems that the worst falls people that I know have taken occured for an unforseen reason, unexpectadely (i.e. a wet root in the wrong place or a hold breaking.) I see no reason why that unforseen reason couldn't occur before you place your first piece. If you place 20 pieces of pro per pitch on average, that gives a 5% chance of each fall being directly onto the anchor. I have begun to use a quad at bolt anchors and it is quite elegant but a nylon equalette has many advantages in my opinion for gear anchors. Does anyone see anything unsafe about what I have above. All it takes is 3 feet of extra cord, it removes a knot from one of the legs and it allows you to clip two strands for a power point and still back up with a locker on the 3rd strand. Can anyone see any reason why the system I pictured above may fail that I am not seeing? Is there a concern about securing the ends into the figure 8's that I am not aware of? If not, I think I will hang my life on it this season.
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vivalargo
Jan 6, 2007, 2:17 AM
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asdf wrote: Yeah, it is a factor 2 fall I am worried about. I realize that you should not plan on factor 2 falls hence the "jesus nut," but they do happen. It seems that the worst falls people that I know have taken occured for an unforseen reason, unexpectadely (i.e. a wet root in the wrong place or a hold breaking.) I see no reason why that unforseen reason couldn't occur before you place your first piece. If you place 20 pieces of pro per pitch on average, that gives a 5% chance of each fall being directly onto the anchor. I have begun to use a quad at bolt anchors and it is quite elegant but a nylon equalette has many advantages in my opinion for gear anchors. Does anyone see anything unsafe about what I have above. All it takes is 3 feet of extra cord, it removes a knot from one of the legs and it allows you to clip two strands for a power point and still back up with a locker on the 3rd strand. Can anyone see any reason why the system I pictured above may fail that I am not seeing? Is there a concern about securing the ends into the figure 8's that I am not aware of? If not, I think I will hang my life on it this season.
Remember that very few people have ever experienced/held a factor 2 fall--not saying that they can't happen, and you shouldn't plan accordingly, but the focus should always be on protecting the belay anchor from direct impact. That's NOT what it's for.
As is, the equalette has redundancy with the two strands. While you can probably find cases where one strand of 6MM (or thicker) nylon broke, I believe there is no existing case of two strands, in working condition, ever breaking outright. The actual forces of most any fall rarely reach such astronomical numbers that dynamic rigging gear--in good shape--simply busts apart. It's much more probably that primary placements should rip out.
So what I'm saying is that, while anything can happen, the probability of both strands of a solid equalette simply busting from loading is almost certainly minute, approachoing zero. There is never a case where all risk can be removed, but focusing on other aspects of the anchor chain that often do fail will probably serve you better than trying to safeguard eventualities that are so small to almost be moot.
JL
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asdf
Jan 6, 2007, 2:35 AM
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Thanks for your responses JL, take solace in that you are offering your much appreciated opinion to someone who has purchased, read and re-read most of your books. So one strand is enough you say, I got it. Now if to serve my own neuroses, if I wanted to have more than two strands does anyone see a problem in the system I suggest up above? To me it seems a little cleaner as there is no knot in the leg of the equallette to accomodate and an extra strand to accomodate my "issues."
Asside from the needless redundancy, does anyone see an issue with the above 3 strand equallette?
Thanks all for looking/responding.
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vivalargo
Jan 6, 2007, 3:02 AM
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asdf wrote: So one strand is enough you say, I got it.
No you don't because I never said ONE strand was enough. The Equalette has TWO strands. The Quad, four. One strand is not enough, ever.
JL
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asdf
Jan 6, 2007, 3:12 AM
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Well that's kinda what my issue is. If the two strands are not the same length, not clipped in with the same type of biner etc. Then you are basically on one strand, then if it breaks you have a similar lode on an identical strand, not good. Obviously you believe this to be an acceptable amount of risk as you believe each of those strands is strong enough on it's own. Yes, there is stretch in the coralette to accommodate small variances in length, but if you clip one biner to two strands, the stress will be more evenly shared by the two strands. I just wish to know if anyone sees an issue with the above rigging aside from perceived redundancy.
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billl7
Jan 6, 2007, 4:10 AM
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asdf wrote: Well that's kinda what my issue is. If the two strands are not the same length, not clipped in with the same type of biner etc. Then you are basically on one strand, then if it breaks you have a similar lode on an identical strand, ....
I don't see a danger in what you suggest except for maybe tieing off the loose ends to backup the figure 8 in case it rolls or something. On the other hand, some tests show that an overhand has less of a tendancy to roll (i.e., in a one arm failure). Back on the first hand, I think an overhand is not as strong as a figure 8 for the usual kind of forces the limiter knots will see (i.e., pulling it tighter). And what if instead of breaking the now doubled strand it breaks one arm of the equalette that has a single piece of pro (3 piece anchor); that seems as similarly likely to break as breaking one strand at the powerpoint. That would cause the powerpoint biner(s) to slide up against the limiter knot in order to arrest the fall. Aren't we then back to relying on 1 strand of cord at the power point? Or couldn't that happen without breakage if the anchor is simply not set up for the actual direction of pull?
This last part is sort of tongue in cheek. I mean, if there is enough concern to put in a 3rd strand at the powerpoint then it seems there is a train of similar thoughts that will tweak the perfectly good equalette into the "elephant strong" Quad.
Bill L
(This post was edited by billl7 on Jan 6, 2007, 4:14 AM)
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vivalargo
Jan 6, 2007, 4:15 AM
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Actually, at the power point, the two strands between the limiter knots (unless you have bungled said knots, the two strands should be the same length) mean you are never on one strand, you're always weighting both strands since you're clipped into and are weighting both. There is not one strand absorbing a lot more than the other strand because the diferences in length should be very marginal if the system is properly rigged. You'll never get the strands perfectly equal, but the differences in length only become meaningful when said differences are in the range of inches, not millimeters.
JL
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ericbeyeler
Jan 6, 2007, 4:24 AM
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asdf wrote: Well that's kinda what my issue is. If the two strands are not the same length, not clipped in with the same type of biner etc. Then you are basically on one strand, then if it breaks you have a similar lode on an identical strand, not good. Obviously you believe this to be an acceptable amount of risk as you believe each of those strands is strong enough on it's own. Yes, there is stretch in the coralette to accommodate small variances in length, but if you clip one biner to two strands, the stress will be more evenly shared by the two strands. I just wish to know if anyone sees an issue with the above rigging aside from perceived redundancy.
Eric
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antiqued
Jan 6, 2007, 5:11 AM
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asdf wrote: I am sure many of you will think I am paranoid, but there is the possibility for the entire force of a fall to land on just one strand of the cordalette. If that one strand fails because the force was too great, what is the chance of having the other strand hold?
I think you should reconsider your fear. Mammut 7mm cord, for example, is rated to 13kN. A UIAA test fall is typically <=9kN, and even if applied to only one strand of the equalette, that load is shared by each side, so the strength is ~20kN (13*2*75% for knot and angle reduction) This is a higher safety margin than most climbing ropes, than most runners on protection, and most protection pieces.
Look at it another way. Many people are climbing on half ropes now only 7.8-8.1mm diameter. So they are taking falls on a single strand not much thicker than the doubled strand you are questioning.
As vivalargo said, back it up with the other strand in the equalette and it should be pretty safe.
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billl7
Jan 6, 2007, 5:17 AM
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ericbeyeler wrote: This [ equalette] is a great setup if used properly.
(I realize that the equalette isn't the only game in town for this.)
Bill L
(This post was edited by billl7 on Jan 6, 2007, 5:44 AM)
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notch
Jan 6, 2007, 11:56 AM
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asdf wrote: I know that nylon 7mm can hold great amounts of force when tied in a prussik loop but does the sliding portion of the equallette count as a loop?
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el_jerko
Jan 8, 2007, 5:44 PM
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In reply to: Afterall, the lead rope is dynamic and so a considerable amount of energy would be used up in breaking the first strand.
Not to be changing the subject, but I have always wondered about this; if the rope stretches and sucks up some energy, then the piece pulls, it seems like the next piece is going to be hit with a more static like load because the rope will have lost some of it's bungee. Is this the case?
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billl7
Jan 11, 2007, 3:08 AM
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el_jerko wrote: In reply to: Afterall, the lead rope is dynamic and so a considerable amount of energy would be used up in breaking the first strand. Not to be changing the subject, but I have always wondered about this; if the rope stretches and sucks up some energy, then the piece pulls, it seems like the next piece is going to be hit with a more static like load because the rope will have lost some of it's bungee. Is this the case?
Bill L
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knudenoggin
Jan 13, 2007, 7:26 AM
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asdf wrote: Just wondering if anyone else out there is worried that the equalette hangs all the safety on just two strands of cordalette? ...
(becket hitches): this gives you an ELET, with double strands of the sling
as the sliding-over part (the "V"), and the V sealed along the top with the
doubled cordelette running between the sheet bends to the ends of the folded
sling. The 6-8mm Dyneema slings will nearly match the 7mm cord, and are great
for letting the 'biners slide (clip both 'biners or a monster locker around both
parts of the sling).
*kN*
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foreverabumbly
Jan 23, 2007, 8:55 AM
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I think also to mention that, even though 1 strand is only 13KN using the two strands around 20KN, the human body (when testing for impact forces etc) can only withstand less than 12KN without injury. with the breaking strain of only 12KN, your body is going to break before your equalette does.
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drfelatio
Jan 23, 2007, 9:21 AM
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Ever since I first learned about the equalette, I noticed its striking similarity to a Sliding-X w/limiter knots. The only differences being the clove hitches used on each strand and the manner in which the lockers are attached at the powerpoint. What I have been wondering is why the lockers are attached that way in the first place? It would seem to me as though we could just clip them in the same manner in which one clips a Sliding-X -- by twisting one of the strands. I know this is required when you only have one locker, why isn't it done when you have two? Would clipping the powerpoint this way eleivate some of the OP's concerns?
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healyje
Jan 23, 2007, 10:11 AM
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I would clip them in an X if I only had one locker at the belay; otherwise clip the individual strands to eliminate the friction of strand on strand.
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billl7
Jan 27, 2007, 6:31 PM
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drfelatio wrote: Ever since I first learned about the equalette, I noticed its striking similarity to a Sliding-X w/limiter knots. The only differences being the clove hitches used on each strand and the manner in which the lockers are attached at the powerpoint. What I have been wondering is why the lockers are attached that way in the first place? It would seem to me as though we could just clip them in the same manner in which one clips a Sliding-X -- by twisting one of the strands. I know this is required when you only have one locker, why isn't it done when you have two? Would clipping the powerpoint this way eleivate some of the OP's concerns?
Bill L, edit ...
I'm pretty sure that clipping the power point with 1 biner and the sliding X wouldn't alleviate the OP's concern since there are still only 2 strands.
The book makes detailed comparisons of when each type of anchor/feature tested out to be best or not: sliding X versus traditional knotted cordalette versus equalette. Get the book and meditate.  
(This post was edited by billl7 on Jan 27, 2007, 7:17 PM)
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niloc
Apr 10, 2007, 7:59 PM
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With the equalette I really want to use both strands to share the load; I just don't feel comfortable with using only one strand plus the other for backup. Two strands of 7mm Mammut (rated at 13kN) is enough for me. There are basically only two options: you use a single biner with a sliding-x or you use two biners on each strand both attached to the same knot. I don't think you can have multiple biners in a sliding-x since the strand with the X would become a lot shorter than the other strand - so you cannot use multiple "single biners on both strands" to minimize the number of biners in the powerpoint.
One acceptable solution (for me) is to use two biners on both strands as my primary hookup plus a single biner on one strand for my backup. (Note that I really am not in the minimalist school "you don't need a backup nor double biners" - but this is for me... and my family ;)
I went to Red Rocks a few weeks ago and it was the first time I used both the equalette and the quad on long multipitch routes. My only problem was with using the equalette in a hanging belay stance: I found it difficult to manage the powerpoint under tension with all the biners and especially when belaying the second with an autoblock at the anchor.
We decided to simply use a single large master biner at the equalette powerpoint with the sliding-x. This allowed a quick & easy clip-in powerpoint. The belayer would also have a backup attachment point on a second locker on only one strand of the equalette. So basically you'd only deal with 2 biners in the powerpoint.
I have read that using a master biner and clipping biner on biner is an acceptable practice among guides but I must say that I don't really like that. Should I reconsider?
Would anyone have other suggestions for making the equalette anchor under tension easier to manage?
Thanks for your input.
Colin.
(This post was edited by niloc on Apr 11, 2007, 1:34 PM)
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