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Holey dogbones, Batman! (Yet another anchor thread)
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blondgecko
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Jul 2, 2012, 8:27 PM
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Holey dogbones, Batman! (Yet another anchor thread)
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So, the discussion on the latest equalette thread got me thinking, and last night I sat down to play with a needle and thread and some old slings. Here's what I mocked up: a "holey dogbone"



Basically, it's just a 2-foot sling with a smaller sling bar-tacked inside it, with a little reinforcement I'll describe below. Topologically, though, it basically is the equalette, just built into a more compact form.

Here's what it looks like set up as a 2-point anchor:



For more anchor points just stack copies:



Of course, this configuration only gets load distribution of 50-25-25 (ideally), but as has been hashed out in a great many threads, this is about the best you can hope for anyway.

In the event of failure, the load remains trapped within the inner loop:



In the first one I made, it was entirely internally redundant (meaning that you'd have to break at least two strands for complete failure), except at two points - here (and its symmetrical equivalent):



Cutting at this point while under load would put all the load onto the top bartack, leading to the inner loop potentially peeling itself all the way out. So, in my second version I added an extra layer of reinforcement here:



... which, unless I've missed something, makes it entirely functionally redundant, meaning just one could be used as the power point.

In terms of handling, each one weighs not much more than the equivalent length nylon sling, and it would take at least half a dozen to weigh the same as a cordelette. They'd still behave perfectly well as long quickdraws. Clip one biner through both end loops, and the other around the bottom end (leave a small gap un-tacked between inner and outer loops on the unloaded strand to clip your biner through, and it'll keep it well-behaved while not falling off the end as soon as you lengthen the draw. On the whole, you wouldn't lose much by replacing all your longer draws with these - just use whatever's left to build the anchor.

So, advantages, as I see them:

- simple and relatively (I've learned to never say completely) foolproof
- lightweight
- versatile - unlike a cordelette, they're still very much functional if necessary mid-route
- ???

Disadvantages

- since it requires bartacking, it will only ever become widely available if manufactured and sold by a gear company (have at it, guys - it's now public domain)
- ??? I'm sure I'll be told below.
Attachments: holey_dogbone.jpg (27.9 KB)
  2pointanchor.jpg (38.4 KB)
  3pointanchor.jpg (41.6 KB)
  single_fail.jpg (36.6 KB)
  closeup_weaklink.jpg (39.3 KB)
  closeup.jpg (38.6 KB)


jt512


Jul 2, 2012, 10:48 PM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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I predict that someone will copy this idea and patent it. I hope you're ok with that.


caughtinside


Jul 2, 2012, 10:56 PM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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Pretty innovative, nice.

I think some guys would go for it even if you can accomplish everything with normal slings.


moose_droppings


Jul 2, 2012, 11:10 PM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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I think it might have an advantage with a 2 bolted anchor where the two bolts are some what close together. It might be more advantageous to make one up out of a four foot runner which would give more leeway for pro that might not always be close together to avoid wider angles in the anchor. This is also where an equallette might have an edge. Just a thought.

Jay may be right with his prediction. It does seem simple, light and versatile in uses.

Edit:
Banz yourself for 5 days for starting another anchor thread.

Laugh


(This post was edited by moose_droppings on Jul 2, 2012, 11:17 PM)


blondgecko
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Jul 2, 2012, 11:37 PM
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Re: [jt512] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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jt512 wrote:
I predict that someone will copy this idea and patent it. I hope you're ok with that.

Yup. Thought about it for a while. Then I thought to myself, "self, you're a research academic in a secure, fairly well-paid job with three patents to your name as it is. If you're going to get rich someday, it probably won't be from selling a new piece of climbing gear."

Besides, having been through the patenting process a few times from a professional perspective, the thought of doing it as a private citizen gives me cold chills. The only thing that really gave me pause is that manufacturers are often only really interested in taking on new products if they have a guaranteed monopoly for a while (i.e. a patent). But the reason for that is to make sure they recoup development costs - and the development costs on something like this are pretty tiny.

Anyway, if it ends up on shelves, consider it my gift to the climbing community. Smile


blondgecko
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Jul 2, 2012, 11:43 PM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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Oh, and if someone somehow does manage to get a patent, I'll happily volunteer as a witness to the inevitable court challenge... in return for an all-expenses-paid family trip to the jurisdiction of the trial. Cool


theguy


Jul 3, 2012, 1:57 AM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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I guess I'm wondering when I would use this.

If the anchor points are this close together and at such similar heights I'm guessing I'm either sport-climbing, in which case I'd just use draws, or trad climbing with a pretty sweet pair of cracks for pro, and would just use bunny-ears.

I use a cordellete/equalette because I can hook up anchor points which are fairly far apart and adjust the limiter knots to match the different heights of the pro (which I end up doing just about all the time: if I'm equaletting, they are rarely in the right spot right off my harness). And since I don't know what I'm going to run into anchor-wise tradding, I'd be carrying the cordellette anyway, so this would be additional rather than replacement gear.

I guess if you're doing lots of tradding on routes you know and which have the right anchor setup, this would be nice.


blondgecko
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Jul 3, 2012, 2:59 AM
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Re: [theguy] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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theguy wrote:
I guess I'm wondering when I would use this.

If the anchor points are this close together and at such similar heights I'm guessing I'm either sport-climbing, in which case I'd just use draws, or trad climbing with a pretty sweet pair of cracks for pro, and would just use bunny-ears.

I use a cordellete/equalette because I can hook up anchor points which are fairly far apart and adjust the limiter knots to match the different heights of the pro (which I end up doing just about all the time: if I'm equaletting, they are rarely in the right spot right off my harness). And since I don't know what I'm going to run into anchor-wise tradding, I'd be carrying the cordellette anyway, so this would be additional rather than replacement gear.

I guess if you're doing lots of tradding on routes you know and which have the right anchor setup, this would be nice.

Well, I've always been a "use the rope" type of traddie myself. Bought a cordelette once, used it twice...

Anyway, I see two options: use a 4-foot or longer sling as suggested by moose above, or simply extend arms as needed using other gear, just as you would when using a sliding x, for example. Remember these were thrown together using the first old slings I found in the cupboard. There's all the usual trade-offs to be made: arm length vs rackability, size of inner loop (range of motion vs. length of possible extension on failure, etc.). In the end it's just another potential weapon in the arsenal.


JimTitt


Jul 3, 2012, 5:15 AM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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There was a (Spanish?) guy touting this concept around the manufacturers a couple of years ago, probably the same person who posted about how to tie this out of a sling which was discussed on here a while ago.
There were some technical issues about using bar tacks due to potential wear from the karabiner but a protective cover was thought to be an acceptable solution.
As far as I know there was no interest in producing them as you need another load of stuff to adjust the lengths of the legs and so while it is neater in itself the end result in practice isnīt. And the Euroīs donīt want any of that equalising stuff anyway so it would never sell, at least over here.
Three layers of Dyneema hybrid bar-tacked together give a load split of 66%/34% for a two-point anchor and 22%/12%/66% for the three point you show.


patto


Jul 3, 2012, 6:08 AM
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Re: [blondgecko] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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I give you extra points for style and beauty with the colour combination with matching biners. Wink

My normal response to these threads is to rubbish the design and say use climbing rope or cordalette. This time I not going down that path (maybe its the beer and my good mood, or maybe its a clever design)

It seems like a useful anchor which, if given the item and a couple of bolts, I wouldn't hesitate to use. (There might even be a market for it!) Laugh

But back to my normal response: Wink

Still the differences between this and a long sling knotted with extension limiters is minimal. Also without the reinforcement the anchor sling strength would be rated at less than the loop rating (load is held by two strands + angle)

Finally the obsession with obtaining an anchor that will survive a cut in any point seems a bit silly really. Redundancy makes sense when there is a non negligible probability of failure. In makes sense to approach some gear placement with this attitude. Equipment failure (rope breakage, sling breakage, carabiner breakage) is pretty much negligible. As such redundancy is not necessary.

A similar comparison are in engineered structures. Redundancy is not considered at all important for most members in most circumstances. What is important is ensuring the maximum expected loads are less than the capacity and ensuring appropriate quality control so that members behave as expected.


(This post was edited by patto on Jul 3, 2012, 6:09 AM)


johnwesely


Jul 3, 2012, 9:37 AM
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How is this different than a knotted sliding x? Am I missing something?


JimTitt


Jul 3, 2012, 10:30 AM
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johnwesely wrote:
How is this different than a knotted sliding x? Am I missing something?

Essentially no. However it looks more `purpose builtī, will be stronger and would allow a manufacturer to charge a bit more. Looking at some of the other offerings on the market this is not to be sneered at.


johnwesely


Jul 3, 2012, 10:58 AM
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JimTitt wrote:
johnwesely wrote:
How is this different than a knotted sliding x? Am I missing something?

Essentially no. However it looks more `purpose builtī, will be stronger and would allow a manufacturer to charge a bit more. Looking at some of the other offerings on the market this is not to be sneered at.

I also just realized that without the twist, it will be much easier to clip multiple carabiners into the master point.


JimTitt


Jul 3, 2012, 11:18 AM
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johnwesely wrote:
JimTitt wrote:
johnwesely wrote:
How is this different than a knotted sliding x? Am I missing something?

Essentially no. However it looks more `purpose builtī, will be stronger and would allow a manufacturer to charge a bit more. Looking at some of the other offerings on the market this is not to be sneered at.

I also just realized that without the twist, it will be much easier to clip multiple carabiners into the master point.

Iīm a bit like Patto here, itīs nice looking and more elegant then knots in slings (which I detest anyway) and well though out. It is also sellable to punters which is half the game and a massive improvement on at least one similar item on sale.
But I couldnīt visualise ever using it, if someone gave me one Iīd probably cut the stitching so I had two slings!


blondgecko
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Jul 3, 2012, 1:12 PM
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Heh - might have known it had already been thought of. Interesting what you say about the load split- is that just because the three-layer construct is too stiff to adjust itself to true 50:50?


JimTitt


Jul 3, 2012, 2:22 PM
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Well you never get to 50:50, the best Iīve got is 58/42 with 10mm dyneema. The 12mm hybrid like you used normally gets 59/41 but stiffening it up and probably the bar tacks push it up a lot, thatīs actually the highest Iīve seen by quite a way. A ring of stainless steel cable would be good though!


blondgecko
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Jul 3, 2012, 3:00 PM
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JimTitt wrote:
Well you never get to 50:50, the best Iīve got is 58/42 with 10mm dyneema. The 12mm hybrid like you used normally gets 59/41 but stiffening it up and probably the bar tacks push it up a lot, thatīs actually the highest Iīve seen by quite a way. A ring of stainless steel cable would be good though!

Interesting. Some sort of stainless eyelet design is also possible, but weight and cost becomes an issue.

One other thing, though: there's no reason why you would need three layers (or, indeed, bar-tacking) all the way across. That third layer is only there to reinforce the joint (as patto said, functionally it's overkill - but I'd hazard that it's probably not so much when it comes to liability). It only needs to be long enough to give a solid overlap on each side. In the middle (where your load should spend most of its time) it can be just the two, unconnected strands. In fact, that's how it is in my mock-up, though that may be hard to see. You'd have to make the inner loop bigger (say, a foot) to make that stretch of a particularly useful length, though.


notapplicable


Jul 3, 2012, 8:37 PM
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Nice. Ultimately superfluous but nice. Given the number of PAS's I've seen floating around the crags, that thing will probably sell just fine.


blondgecko
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Jul 3, 2012, 8:50 PM
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notapplicable wrote:
Nice. Ultimately superfluous but nice.

I bet you could find someone to say that for any piece of climbing gear - and that includes the rope. Laugh


Mark_Hudon


Jul 3, 2012, 9:56 PM
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Can't say I'd use it but I applaud the creative thinking!


patto


Jul 4, 2012, 3:13 AM
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blondgecko wrote:
notapplicable wrote:
Nice. Ultimately superfluous but nice.
I bet you could find someone to say that for any piece of climbing gear - and that includes the rope. Laugh
So true.

I like it! Wink But I still think it is not needed. But given the disparaging comments from the usual suspects like myself are so extremely mild I'd almost go as far as saying this is the best thing since the sling & the cordalette. Wink But I still use the climbing rope.

Anyway well done! :-)


blondgecko
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Jul 4, 2012, 3:29 AM
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Re: [patto] Holey dogbones, Batman! (Yet another anchor thread) [In reply to]
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Awww, man - so you mean I put on my asbestos undies for nothing? Do you have any idea how much these things itch?


JimTitt


Jul 4, 2012, 9:42 AM
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blondgecko wrote:
Awww, man - so you mean I put on my asbestos undies for nothing? Do you have any idea how much these things itch?

Dream on, after the Adatesman fiasco we hacked the server and when a moderator clicks on a thread they get the computer-generated family-friendly version. You can always tell the difference because jt512 is pleasant though programming this wasnīt easy, we had use Mother Teresaīs psychological profile in the end.


blondgecko
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Jul 4, 2012, 4:23 PM
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JimTitt wrote:
blondgecko wrote:
Awww, man - so you mean I put on my asbestos undies for nothing? Do you have any idea how much these things itch?

Dream on, after the Adatesman fiasco we hacked the server and when a moderator clicks on a thread they get the computer-generated family-friendly version. You can always tell the difference because jt512 is pleasant though programming this wasnīt easy, we had use Mother Teresaīs psychological profile in the end.

LaughLaughLaugh


qwert


Jul 6, 2012, 6:15 AM
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I'd might get one because
a) I am a gear whore
and
b) looks like this could be an easy way to "equalize" two pieces mid pitch. At least asier than using a 30cm quickdraw sliding X.

But other than that i think it solves a problem that does not really exist.

And i wonder that no one has yet posted that link:
http://www.rockclimbing.com/...rum.cgi?post=2363707

qwert

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