Author Topic: practical uses for ring-loading knots?  (Read 4312 times)

Andy

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practical uses for ring-loading knots?
« on: November 30, 2012, 09:10:09 PM »
Starting a new thread for this to tidy up another thread that was in danger of going off topic.

On that thread, Dan explained ring-loading a knot.

Quote
That term means"loading the eye of an eye knot by expansion

Thank you for explaining, Dan.
To rephrase, it sounds like the action on the loop is similar that of holding a metal ring with two hands on opposite sides of the ring, and pulling the hands away from each other as though one were trying to break the ring. After reading your explanation, I looked in a mountaineering book and saw drawings of how they use ring loading.

My memory may be foggy, but at the moment I don't recall having to do that to a loop (pulling it apart from different directions), although if I had to I would go to the Alpine Butterfly.

Apart from mountaineering, can anyone think of practical situations where one might need to do that?

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SS369

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Re: practical uses for ring-loading knots?
« Reply #1 on: November 30, 2012, 09:25:49 PM »
Hi Andy.

Though I can't at present think of a real world application of a ring loaded loop per se, I can think of where similar forces come into play. In the instance where you might use a loop of choice around a very large diameter object and the "knot" part is close to the encircled entity. As the load causes the eye loop's legs to spread towards 180 degrees, the connection to each other deforms and could come undone or capsize.

I feel confident that someone out there has seen this used as you ask, perhaps "knots in the wild".

roo

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Re: practical uses for ring-loading knots?
« Reply #2 on: December 01, 2012, 01:04:12 AM »
Apart from mountaineering, can anyone think of practical situations where one might need to do that?
Any time you throw a loop over an object that gets larger as you travel from the end (think cone or wedge shape), there is a potential for the legs of the loop to be pulled in opposite directions, roughly. 

I'm sure there other odd jobs that call for a sling combined with a loop.

Aside from need, such loading can also occur from snagging of some foreign object and having it or the intended object travel.
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Andy

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Re: practical uses for ring-loading knots?
« Reply #3 on: December 01, 2012, 12:17:49 PM »
Hi SSS369, hi Roo

Thanks for sharing your thoughts.
Apart from inadvertent or accidental configurations that result in forces that mimic ring-loading, it sounds like apart from mountaineering, as in my case, neither of you have a clear picture of a time when one would deliberately make a loop with the intention of ring loading it?
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roo

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Re: practical uses for ring-loading knots?
« Reply #4 on: December 01, 2012, 05:54:06 PM »
Hi SSS369, hi Roo

Thanks for sharing your thoughts.
Apart from inadvertent or accidental configurations that result in forces that mimic ring-loading, it sounds like apart from mountaineering, as in my case, neither of you have a clear picture of a time when one would deliberately make a loop with the intention of ring loading it?
When I put a loop over a wedge-shaped object and size the loop so it can only go so far, I am very aware of such loading.  There's no accident involved. 

You could also pull a sling-suspended object with the standing part of the loop, such as with a overhead rail system.  Such a system would, by design, have the legs of the loop being pulled in opposite directions.
« Last Edit: December 01, 2012, 06:21:16 PM by roo »
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Andy

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Re: practical uses for ring-loading knots?
« Reply #5 on: December 03, 2012, 06:26:49 AM »
Hi Roo,

Quote
There's no accident involved.

In that post, I was looking for the right word to describe configurations that result in forces that mimic ring-loading as a by-product of the structure attained, rather than designing an empty ring and loading it at the sides. I came up with "inadvertent" and felt that wasn't quite the right word---apparently you did too.

What I meant was, apart from mountaineering, so far it doesn't sound like we've come up with a clear picture of a situation where one would think "Ooo, for this application I'll make an empty loop, and pull it apart at the sides".

Regards,

Andy
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Dan_Lehman

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Re: practical uses for ring-loading knots?
« Reply #6 on: December 04, 2012, 07:06:50 AM »
Starting a new thread for this to tidy up another thread that was in danger of going off topic.

On that thread, Dan explained ring-loading a knot.

Quote
That term means"loading the eye of an eye knot by expansion

...  After reading your explanation, I looked in a mountaineering book
and saw drawings of how they use ring loading.

Really?!  How did they use it, in that book?

Quote
I would go to the Alpine Butterfly.

Because ... ?  And since the concern here is about the
knot's failure at the end of the line, you'll need to specify
which orientation of the asymmetric linesman's loop you want!

As for practical situations, I don't see the wedge issue
--what's to drive the wedge to ring-load?

But if one e.g. wanted to have a dog-leash extender for
a pair of leashes, there's be the chance that dogs chased
different squirrels, and that could ring-load an eye joining
the two short leashes.  ("squirrels" : are we talking knots
or nuts, here?)


 ;)


Andy

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Re: practical uses for ring-loading knots?
« Reply #7 on: December 04, 2012, 08:33:19 AM »
Hi Dan,

Running out of time today, but briefly:

Quote
Really?!  How did they use it, in that book?

P. 139 of Craig Connally's Mountaineering Handbook: "Ring loading" or "wrong loading" refers to applying a perpendicular load to the strands as they enter the knot. This can arise if someone else, a rescuer perhaps, clips to you. (...) Avoid loading a figure eight this way because it'll fail by rolling over itself at surprisingly low loads (...) The Yosemite bowline does not have this problem, but clipping to its loop is a bad habit anyhow.

Why the Alpine Butterfly? I've always heard it's safe to pull it from any side, so that's just my go-to loop when I want something grunty. I might well be delusional though.

Your idea for a practical application of ring loading sounds great, but as far as I'm aware, there are no squirrels in New Zealand. Is there another way I could test it out?

Regards

Andy
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