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Sewn vs Tied Runners


Jeff_T

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Though it was stated in the linked post, it bears repeating. The biggest problem with tied runners is that they can untie themselves due to cyclic loading. The tails slowly get closer and closer to the knot until they pull through.

 

This isn't a big deal if you pay attention to your runners and retie them every once in awhile. But it is imperative that you do pay attention to the runners and their knots over time.

 

Jason

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There is a trick with the 9/16" tubular that takes care of the tails and "supposedly" decreases the slippage.

 

Tie a single water knot and move it away from the bitter end.

 

Then, open up one of the tubular webbing and sleeve the other end into the open hole.

 

Be sure you have plenty of "tail" both inside and out, before you work the waterknot back over the sleeved portion.

 

Check by feel to insure there is extra webbing inside, as well as visually inspecting the outside tail.

 

I have climbed on this setup for several years without any noticable slippage.

 

wave.gif

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Hey MisterE, that's called a "Beer Knot." It works with 1" tubular as well. It's cleaner, but slightly more bulky than a water knot.

 

Thanks. I didn't know the name. Basically an overhand knot slid to the side until the sleeving is done:

 

overhand.jpg

 

It ends up being an sleeved waterknot.

 

No, Ted. The knot won't come undone. That's the point. rolleyes.gifrolleyes.gif

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That's pretty darn cool, if you ask me. It should be stronger than a water knot. My only concern would be the ease with which you can monitor the length of the tails when buried out of sight.

 

In a similar vien, there are some single braid splicing techniques from the sailing world that could applied to tubular webbing. These are very strong and can be executed safely by the amateur.

 

Example: http://www.ropeinc.com/sp12b_sbraid_eye_lock_stitch.htm

 

The splice may be too long to be worth the weight. Maybe for a double runner.

Edited by catbirdseat
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There is a trick with the 9/16" tubular that takes care of the tails and "supposedly" decreases the slippage.

 

Tie a single water knot and move it away from the bitter end.

 

Then, open up one of the tubular webbing and sleeve the other end into the open hole.

 

Be sure you have plenty of "tail" both inside and out, before you work the waterknot back over the sleeved portion.

 

Check by feel to insure there is extra webbing inside, as well as visually inspecting the outside tail.

 

I have climbed on this setup for several years without any noticable slippage.

 

wave.gif

Is there any trick to getting one end to sleeve into the other? I should think you would need a fid to do that. The weave may be too tight to get the fid to exit.
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There is a trick with the 9/16" tubular that takes care of the tails and "supposedly" decreases the slippage.

 

Tie a single water knot and move it away from the bitter end.

 

Then, open up one of the tubular webbing and sleeve the other end into the open hole.

 

Be sure you have plenty of "tail" both inside and out, before you work the waterknot back over the sleeved portion.

 

Check by feel to insure there is extra webbing inside, as well as visually inspecting the outside tail.

 

I have climbed on this setup for several years without any noticable slippage.

 

wave.gif

Is there any trick to getting one end to sleeve into the other? I should think you would need a fid to do that. The weave may be too tight to get the fid to exit.

 

Another fisherman! I haven't heard the term "fid" for a few years!

 

I usually take a piece of coathanger and embed it partway into the webbing, then you can sleeve it and pull the wire.

 

wave.gif

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Sorry to add to the flogging of a thoroughly dead horse, but this is one of my favorite subjects (I have a list, just ask).

 

Runners tied with beer knots (one strand inside the other in a simple overhand knot) are superior to water knots for a couple of reasons: they don't self-untie and they preserve about 80% of the runner strength compared to about 50% for water knots. Beer knots can be untied without too much trouble, easier than a double fisherman (which is what you'd use to re-tie an opened nylon runner). Water knots untie themselves when subject to repeated low loads (like body weight; think: rappelling).

 

To tie a beer knot you need at least 10 inches of overlap with 1-inch webbing and at least 8 inches with 11/16th inch webbing. I can't imagine using beer knots with 9/16 webbing, due the pain of getting one strand inside the other; even 11/16 is questionably worth it--use double fisherman knots instead. I use a chop stick to finagle one strand inside the other.

 

Even better, sew your own runners in nylon webbing. You can't do this with Spectra/Dyneema webbing or thread, but according to The Mountaineering Handbook, "if you can find the right thread (DB92 bonded polyester) and know how to pick the needle and set bobbin tension" you can sew you own runners on a beefy home machine. Home-sewn runners can be as strong as commercially sewn versions, as strong as the webbing itself. That won't be 22 kN for 9/16th inch webbing, but I'd challenge anyone to come up with a realistic climbing scenario where 22 kN would be approached.

 

I admit to sewing my own, have for years, and I've tested the results. The only requirement is getting enough stitches, and that's a matter of dividing the strength of the webbing by the half the strength of the thread and adding a modest safety margin. You can make the sewn section stronger than the webbing itself just by sewing enough stitches. (Don't disagree unless you've actually done the testing.) Sewn runners (commercial or DIY) work because the webbing and threads distort enough so that the load is shared among all (except for Screamers, which are sewn differently).

 

Why would you want to sew your own runners? To make cheap, light 48-inch runners (in 9/16 or 11/16 webbing, which are hard to find commercially) that are multipurpose (can be used to make Klemheist knots that hold on wet or snowy ropes where Spectra/Dyneema runners might not). Also, to make extra long runners on pro, potentially saving the addition of an extra runner and biner. (If the pro will hold 10 kN, the stitching only needs to hold half that, so pro runners don't have to be as strong as separate runners--in principal). To make runners that you can cut and re-tie around a natural feature; Spectra/Dyneema runners won't work because it does not reliably hold knots. Also, nylon webbing, unlike Spectra/Dyneema, does have some energy absorption, comparable to static climbing rope, so "equalized" anchors made with them might actually be closer to real equalization.

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...this is one of my favorite subjects (I have a list, just ask).

 

After reading with rapt attention your erudite treatise on synthetic polymer runner construction and the potential applications thereof, I, for one, would find it most elucidating to hear what your other favorite subjects are.

 

The list please.

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Yo, Alpinfox! Wussup wid dis "show me your list" bidniss? Can't you see from my profile that I'm a lurker? Besides, it's totally OT.

 

But in the spirit of good clean fun... I'm especially interested in (mainly in the contexts of mountaineering and ski mountaineering):

>complex anchors and why SRENE is mostly bogus

>performance nutrition

>training for alpinism

>pulley, rescue, and autoblock systems in the real world

>fast and light climbing tools and techniques

 

Elucidatin' enough fer ya?

And how do y'all know it isn't Ms Tumblemark ;-) wave.gif

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Yo, Alpinfox! Wussup wid dis "show me your list" bidniss? Can't you see from my profile that I'm a lurker? Besides, it's totally OT.

 

But in the spirit of good clean fun... I'm especially interested in (mainly in the contexts of mountaineering and ski mountaineering):

>complex anchors and why SRENE is mostly bogus

>performance nutrition

>training for alpinism

>pulley, rescue, and autoblock systems in the real world

>fast and light climbing tools and techniques

 

Elucidatin' enough fer ya?

And how do y'all know it isn't Ms Tumblemark ;-) wave.gif

 

 

Those are nice nice topics, care to elaborate Ms. Tumblemark?

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Yo, Alpinfox! Wussup wid dis "show me your list" bidniss? Can't you see from my profile that I'm a lurker? Besides, it's totally OT.

 

But in the spirit of good clean fun... I'm especially interested in (mainly in the contexts of mountaineering and ski mountaineering):

>complex anchors and why SRENE is mostly bogus

>performance nutrition

>training for alpinism

>pulley, rescue, and autoblock systems in the real world

>fast and light climbing tools and techniques

 

Elucidatin' enough fer ya?

And how do y'all know it isn't Ms Tumblemark ;-) wave.gif

 

 

Those are some nice topics, care to elaborate Ms. Tumblemark?

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