Author Topic: Rigging Y-Hangs  (Read 4793 times)

Offline ah147

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Rigging Y-Hangs
« on: October 05, 2013, 10:48:44 pm »
Hi All,

Still new to caving but have ending up doing a little rigging (for single easy pitches, i.e. Valley Entrance, Giants pitches) and just got a little question.

All the time so far I have been using a figure eight on a bight and then on the rope going down an alpine butterfly to equalise to a second bolt. This also allows me to rig a safety line with ease on the walk up the Y-hang.

Last night, on a pitch on a straight walk to the Y-hang (no bolts for safety line) I saw some fixed rope rigged as a bowline on one bolt, then the tail going up to the other bolt with a figure 8 on it.

That seemed a real easy way to equalise and make a Y-hang quickly (with the bonus of not required biners if its on P-bolts) and it just got me thinking, is it a good way to rig? And made me think of my own complicated way, is there an easier way?

Sorry, I know its a bit vague and random.

Cheers

Ash

Offline Alkapton

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Re: Rigging Y-Hangs
« Reply #1 on: October 06, 2013, 02:17:18 am »
Personally I use the bowline/figure 8 combination only when there cant be hangers so you cant use mallions.   For instance when using trees or stall instead of hangers.

I don't like bowlines because I think if one belay fails the knot can slip too easily.

Where hangers are available I always use either 'bunny ears' figure 8 or figure 8 on the bight.  There is a difference, figure 8 on the bight will give you a third loop at the other end of the knot which can be useful as ie. extra foothold at a rebelay.
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Offline Gollum

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Re: Rigging Y-Hangs
« Reply #2 on: October 06, 2013, 06:56:30 am »
I use that method sometimes ash. I also use a re-threaded bowline and save on two krabs at the start of Garlands. You will get loads of different opinions about rigging. I always ask myself 1) is it safe 2) is it easy for the people i'm caving with to get on 3) will it be easy for the people i'm caving with to get off. If the answer is yes to those 3 questions then I'm happy
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Offline Joe90

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Re: Rigging Y-Hangs
« Reply #3 on: October 06, 2013, 07:15:59 am »
There are many ways to rig Y hangs, personally I use a running bowline, Fig 8 and alpine butterfly, Bunny ears or whatever else seems to be the most appropriate for the situation. The more you know and learn, the more diverse your skill set, the more versatile you become the easier you will find rigging and dealing with problems.
As Gollum says, If its safe and easy to use then why not?
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Offline GT

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Re: Rigging Y-Hangs
« Reply #4 on: October 06, 2013, 08:29:15 am »
If you have a look at Andy Sparrows website he's put together some short videos on how to rig the way you described.

Offline Cap'n Chris

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Re: Rigging Y-Hangs
« Reply #5 on: October 06, 2013, 08:45:03 am »
There are many ways to rig

Indeed.

Online glyders

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Re: Rigging Y-Hangs
« Reply #6 on: October 06, 2013, 09:38:47 am »
I'd echo the 'do whatever is safe and works'.

One that is used a lot in the situation you described as it requires no krabs/maillons and minimal rope is:
Tie a bowline with a long tail onto one anchor. Tie this tail to another anchor with another bowline. Equalise using the the first bowline.
I first met this back on my LCL1 training course. Having seen it I couldn't work out why I hadn't worked it out before. Since then I have used it a lot rigging for all sorts of things, not just caving.

Offline Cap'n Chris

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Re: Rigging Y-Hangs
« Reply #7 on: October 06, 2013, 10:36:53 am »
I'd echo the 'do whatever is safe and works'.

One that is used a lot in the situation you described as it requires no krabs/maillons and minimal rope is:
Tie a bowline with a long tail onto one anchor. Tie this tail to another anchor with another bowline. Equalise using the the first bowline.
I first met this back on my LCL1 training course. Having seen it I couldn't work out why I hadn't worked it out before. Since then I have used it a lot rigging for all sorts of things, not just caving.

Provided the rigger is safe while leaning out over the pitch head, tho', naturally.

Offline Fulk

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Re: Rigging Y-Hangs
« Reply #8 on: October 06, 2013, 11:13:42 am »
With regard to rigging, we all know the figure of 8 bunny's ear that produces two loops; if you take the same approach to the overhand knot you can tie an 'overhand bunny's ear' knot that also has two loops, uses a tad less rope and is a bit easier to adjust. Can anyone give a reason why this should not be used? Or is it safe?

Also, could you use an 'inline figure 8' (Fig 68, p.76, ACT) in lieu of a butterfly (it would have to be the other way yup, of course, with respect to the figure in ACT)?

Offline Joe90

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Re: Rigging Y-Hangs
« Reply #9 on: October 06, 2013, 12:35:30 pm »
The 'overhand bunny's ear' wouldn't be unsafe, but could be harder to untie than using an 8.
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Offline Joe90

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Re: Rigging Y-Hangs
« Reply #10 on: October 06, 2013, 12:37:45 pm »
I meant to add, If loaded heavily to that last one...
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Online glyders

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Re: Rigging Y-Hangs
« Reply #11 on: October 06, 2013, 03:42:12 pm »
Provided the rigger is safe while leaning out over the pitch head, tho', naturally.
Indeed. I had read the situation in the OP as being one where the rigger didn't have to do so (perhaps the anchors were back from the pitch head).

Offline ah147

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Re: Rigging Y-Hangs
« Reply #12 on: October 06, 2013, 04:15:50 pm »
Aye, I was talking about anchors that don't require a safety/handline going up to them.

Offline Bob Mehew

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Re: Rigging Y-Hangs
« Reply #13 on: October 06, 2013, 08:56:02 pm »
With regard to rigging, we all know the figure of 8 bunny's ear that produces two loops; if you take the same approach to the overhand knot you can tie an 'overhand bunny's ear' knot that also has two loops, uses a tad less rope and is a bit easier to adjust. Can anyone give a reason why this should not be used? Or is it safe?


Though I don't have quotable knot strengths, I am moderately confident that such an overhand would be weaker than the equivalent fig 8.  In addition, I suspect it would be more difficult to untie.

The real question is not whether something is safe - SRT cannot be as safe as say using a staircase (to pick an absurd example) but whether a choice is optimum in not only relative safety terms but also tying it correctly, usability, ability to cope with misuse (see http://ukcaving.com/board/index.php?topic=14580.0  for example), untying it and no doubt other contributors will come in with other factors which should be taken into account.  Hence the suggestions of different knots for different situations.

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Re: Rigging Y-Hangs
« Reply #14 on: October 06, 2013, 09:46:51 pm »
SRT cannot be as safe as say using a staircase (to pick an absurd example)
Our H&S advisor at work threw a fit when he found me painting stood on what was effectively a set of stairs. When I rocked up the next day and hung just above the stairs in my SRT rig he was happy (once I'd pre-empted him by making a point about EU regulations about needing two ropes didn't apply to outdoor instruction).

Offline ah147

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Re: Rigging Y-Hangs
« Reply #15 on: October 06, 2013, 09:48:51 pm »
The general consensus on knots is the larger the knot (so the curvature is not as much) the strength is greater.

And to answer my original consensus, it would seem that nothing is wrong as long as the knots are well tied, suitable for the directions of load, and the anchors are equalised?

Offline Fulk

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Re: Rigging Y-Hangs
« Reply #16 on: October 06, 2013, 10:50:52 pm »
Quote from Alkapton:
Quote
I don't like bowlines because I think if one belay fails the knot can slip too easily.

Some effort has been put into this problem with bowlines; I recently came across an analysis of bowlines in a paper in the Internet called . . . err . . . 'An analysis of bowlines' (I think). Anyway, the author analyses several bowline modifications to see which is not only strong but also stable, and comes up with the 'End Bound Single Bowline', which he illustrates in a couple of pictures.

I decided to try and work out how to tie it from  the pictures . . . it took me ages (but then, who knows, I may be topologically challenged). Anyway, here you have a sturdy, strong bowline, and if you want to waste hours of your life, look it up and try and work out how to tie it.

I guess, though, that a figure 8 loop would work just as well!!!

Offline ianball11

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Re: Rigging Y-Hangs
« Reply #17 on: October 07, 2013, 12:28:25 am »
I think you mean this superb work updated in July?

http://www.paci.com.au/downloads_public/knots/Bowlines_Analysis.pdf

A sailor once told me they use a extra wrap on a bowline and called it a better bowline!
She also said a bowline is only half the job, as it needs a stopper to finish it.
This guy shows how many bowline derivatives there are!
http://www.morethanknots.com/bowline/BK_Pics_1.html

and here is a long long long blog on natural fibre knot strength which makes interesting reading.
http://allaboutknots.blogspot.co.uk/2010/11/knot-strength-structures-that-make.html






Offline ah147

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Re: Rigging Y-Hangs
« Reply #18 on: October 07, 2013, 12:53:03 am »
Interesting way to do a bowline that doesn't loosen as easily is a clove hitch instead of just a loop. So "rabbit comes out the clove hitch, round the tree, back into the clove hitch"

Finished with a double fishermans still.

Thats what I use to tie into climbing. Stays done up for days on end with constant loading and unloading.

Offline TheBitterEnd

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Re: Rigging Y-Hangs
« Reply #19 on: October 07, 2013, 09:16:52 am »
Various knot types have been discussed on a variety of threads recently and whilst it is interesting to understand this stuff; surely having a few knots that you can tie reliably is the safest approach on the grounds that human error is probably more likely than rope/knot failure for properly tied knots?
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Offline Alkapton

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Re: Rigging Y-Hangs
« Reply #20 on: October 07, 2013, 10:04:38 am »
Keep it simple.    Use what everyone understands.  There are loads of alternatives but everyone understands fig 8's.   What I think is best y hang knot (decorative triple crown in the bight) is a knot I never use because hardly anyone knows it and people will look with wonder wondering if it is safe.  So I stick with fig 8 wherever possible - simples.
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Offline JasonC

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Re: Rigging Y-Hangs
« Reply #21 on: October 07, 2013, 07:38:20 pm »
Various knot types have been discussed on a variety of threads recently and whilst it is interesting to understand this stuff; surely having a few knots that you can tie reliably is the safest approach on the grounds that human error is probably more likely than rope/knot failure for properly tied knots?

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Offline Joe90

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Re: Rigging Y-Hangs
« Reply #22 on: October 10, 2013, 07:40:28 am »
This was a great thread,
Its got me learning new knots, sat in the office playing with prussic cord.
Ill say I'm bettering my understanding of my workplace if I get caught....  :ang:
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Online Roger W

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Re: Rigging Y-Hangs
« Reply #23 on: October 10, 2013, 09:21:47 am »

Its got me learning new knots, sat in the office playing with prussic cord.


That reminds me of the caver who died while doing SRT on drugs.

He was using prussic acid...

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Offline ah147

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Re: Rigging Y-Hangs
« Reply #24 on: October 10, 2013, 09:49:02 am »
Prussics an awesome knot. Well worth using in all three forms. I don't know the names but one the loop comes out the middle, one out the bottom and through the top loop, then another with loops top and bottom then you clip both into a biner and you effectively have a handled jumar.

This along with the trick with two biners that gives you a reasonably effective but inefficient locking pulley and an Italian hitch (I KNOW THE NAME OF A KNOT) are all really useful

Offline ian mckenzie

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Re: Rigging Y-Hangs
« Reply #25 on: October 10, 2013, 07:46:39 pm »
I saw some fixed rope rigged as a bowline on one bolt, then the tail going up to the other bolt with a figure 8 on it.
Am I missing something... doesn't a bowline pop thru if you pull its tail and the loop in opposite directions?  Doesn't everyone tie off a bowline's tail onto its loop to avoid it's being tugged?

Offline ian mckenzie

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Re: Rigging Y-Hangs
« Reply #26 on: October 10, 2013, 07:54:12 pm »
OK I tried it, and I see now that as long as the standing rope is weighted, the bowline cannot come undone.  It could only happen if you seriously weighted the tail inbetween the two knots (cowstail clip-in?).

Offline Chocolate fireguard

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Re: Rigging Y-Hangs
« Reply #27 on: October 10, 2013, 08:02:47 pm »
I saw some fixed rope rigged as a bowline on one bolt, then the tail going up to the other bolt with a figure 8 on it.
Am I missing something... doesn't a bowline pop thru if you pull its tail and the loop in opposite directions?  Doesn't everyone tie off a bowline's tail onto its loop to avoid it's being tugged?

That was my first thought , but it was wrong - I had to get a bit of rope and tie it as Ian described before I realised.
Pulling the tail and the live rope in opposite directions, which is what would happen if the first bolt fails, only seems to tighten the bowline.
It`s pulling the tail and its side of the loop in opposite directions that pops the knot.