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Holey dogbones, Batman! (Yet another anchor thread)
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surfstar


Jul 6, 2012, 9:53 AM
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Re: [johnwesely] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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johnwesely wrote:
How is this different than a knotted sliding x? Am I missing something?

You're knott missing a thing.


Double length nylon sling - add knotts when needed. $6-8, $2 if you tie your own loop.


blondgecko
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Jul 7, 2012, 3:27 AM
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Re: [surfstar] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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surfstar wrote:
johnwesely wrote:
How is this different than a knotted sliding x? Am I missing something?

You're knott missing a thing.


Double length nylon sling - add knotts when needed. $6-8, $2 if you tie your own loop.

The long (loooooong) series of threads that led eventually to the equalette a few years back came about because the sliding X isn't actually all that great at equalizing. The wrap around the biner creates enough friction to make the load distribution surprisingly asymmetrical. The novelty in the equalette was that it did away with the wrap, significantly improving the biner's freedom to move and equalize without compromising safety. As I said in the OP, this design is functionally equivalent - just ready-made and somewhat streamlined.


surfstar


Jul 7, 2012, 7:37 AM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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and the bodies keep piling up! Damn you, sliding X!!! You bastards.

Two bomber bolts don't need equalization anyways.


patto


Jul 8, 2012, 5:36 AM
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Re: [surfstar] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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surfstar wrote:
Two bomber bolts don't need equalization anyways.

Agreed. I proceed with the whole anchor routine primarily to achieve minimise shock loading and provide redundancy.

The only time I go for better equalisation is when I place tiny nuts (5kN and below). If I have two near each other then I'll use a sliding-X.


blondgecko
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Jul 9, 2012, 5:19 PM
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Re: [surfstar] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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surfstar wrote:
and the bodies keep piling up! Damn you, sliding X!!! You bastards.

Two bomber bolts don't need equalization anyways.

A couple of points:

1. The various anchor discussions in The Lab have almost exclusively been about optimising trad anchors. I'm sure you'll find very few people who disagree with your statement that solid bolts don't need equalization. Marginal gear, on the other hand...

and

2. There's no harm in playing around to improve upon and/or optimise existing methods, even if current methods work well. If you disagree, perhaps The Lab is not the place for you.


wivanoff


Jul 10, 2012, 4:11 AM
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Re: [patto] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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patto wrote:
The only time I go for better equalization is when I place tiny nuts (5kN and below). If I have two near each other then I'll use a sliding-X.

I assume you're not talking about anchors here but, rather, running belays along the route (?)

I sometimes carry a 2 foot sling with pre-tied limiter knots for use when placing tiny nuts. Since the nuts are likely to blow out at low loads anyways, do you see any advantage to clipping only ONE stand between the limiter knots? This would be an attempt to eliminate friction from the sliding-x and actually get equalization on the micro-nuts.

I suppose I could clip one carabiner into each strand equalette style. Do you see any advantage/disadvantage in either method?


jktinst


Jul 13, 2012, 10:18 AM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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The anchor systems I have seen to date that have 2 redundant & extension-limited strands bearing the central locker and one or two additional strands closing the loop to lock it in were based on the following 3 systems:
- a single strand folded in an S shape, as in the mexican system discussed in the other thread mentioned here. This has a single locking strand, which means less clutter and weight.
- one huge sling looped so as to create a smaller ring inside a larger one (havenít been able to retrace the original reference on this one so if someone has it, please pitch in): this gives the less efficient two strands for locking or 3 strands for bearing.
- two separate slings, a smaller one inside a larger one as in the holey dogbones system discussed here and other cord-based ones. In addition to the two locking strands this also has the downside of having two sling-closing knots or bar-tacks.

The main advantages of these systems are that:
- only one central locker is required (as opposed to two for the equalette);
- they have the absolute minimum amount of friction (no squeezing of the strands between the 2 lockers when they are loaded, as in the equalette; and no crossings of strands or clutch effect, as in the sliding X).

The main drawback of these systems is that they are not adjustable in the field. Even if knots are used instead of bar-tacks to create the extension-limited central system, moving those knots in the field to adapt to an asymetrical belay configuration is not realistic because it is not just a matter of loosening and shifting the knots. You have to undo them completely, refold the cord in a new S shape or move the smaller loop to one side of the larger one and redo the knots.

My take on these systems is that they are most useful to equalize 4 not-so-bomproof pros, as shown, using a system inspired from one proposed by healyje a long time ago. This is where, in my mind, it becomes critical to have the best possible dynamic equalization with the most even distribution and the least amount of friction, and where it becomes worthwhile to take the time to build a system that will achieve that over all 4 pros. Of course, thereís a good chance that these pros will be all over the place instead of neatly lined up so the system needs long arms to avoid having to add several extra biners and slings to reach the pros. These long arms make undoing and redoing the knots in the field particularly impractical.



This poor field-adjustability led me to switch to the more easily adjustable system shown. It is essentially one long cord sling with two Fig8s delimiting 2 central strands, to which a third locking strand is added once the Fig8s have been shifted to the correct positions for the belayís specific configuration. This locking strand is rethreaded once through each Fig8 and backed-up with cloves on the secondary lockers. As an alternative to clipping these secondary lockers directly through the extension-limiting Fig8s as suggested by healyje, it is possible to set up each secondary arm and its Fig8 as 2 bunny ears: a tiny one for clipping the locker and a long one for the equalized/ extension-limited arms, as described recently by Neoshade. http://www.rockclimbing.com/...ring=elette;#2542669

For 3-pro anchors, I actually prefer to use stacked sliding Xs (or in my case, sliding double Xs) because I can take advantage of the friction to achieve a better load distribution than the theoretical 50:25:25. This involves setting up the "50" arm on the same side as the probable load, as I discussed in one of my last posts to Neoshadeís thread. Since I reserve the fancy system for equalizing 4 or more somewhat iffy pros, I carry only one on multipitch trad routes that do not have bolts at the belay stations and park it on the belayerís harness. If I were to come to the end of a pitch and find that I have no choice but to set up this kind of 4-pro belay anchor, Iíd find a way to quickly and temporarily rig it well-enough to bring up the second and Iíd replace it with the fancy one for the next lead. However, Iíve not had to use this system for real yet since I came up with it and thatís just fine by me.

(This post was edited by jktinst on Jul 13, 2012, 12:30 PM)

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