Which knots for Y hangs?
- Thread starter tobyk
- Start date
Jon
Member
The other reason for terminating the traverse at the y hang bolt is that you can stack your clients or mates on the traverse closer to the y hang without it affecting the y hang. If your traverse goes straight into the y hang knot then someone leaning on the traverse line will move the y hang rope. More of a comfort / confidence thing than safety.JasonC said:
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JasonC
Well-known member
mikem said:
Yes, I think that was the main point.
As to why separate krabs were recommended - I don't know. I can't recall pros and cons being discussed, though perfectly good reasons have been offered here.
I'm not saying everyone should use this approach, or even that I do, just that it was on the course. Courses are led by instructors who spend lots of time discussing different techniques and who regularly lead novice trips, so are keen to use 'best practice' at all times.
For me, I'm happy with 'good-enough practice'
Mike Hopley
New member
One more reason for possibly taking the traverse up to one of the Y-hang anchors: it simply changes the position of the traverse line, which can change the effective footholds, and also whether the traverse line itself is getting in the way of cavers as they approach the pitch head.
Depending on the pitch, it could make things easier or harder. Mostly I just use a double-loop knot (fusion), but sometimes I like this "instructor style" rigging.
Personally I wouldn't see the extra krab as routinely necessary here, but it's certainly good to consider how krabs might get loaded.
Depending on the pitch, it could make things easier or harder. Mostly I just use a double-loop knot (fusion), but sometimes I like this "instructor style" rigging.
Personally I wouldn't see the extra krab as routinely necessary here, but it's certainly good to consider how krabs might get loaded.
Jon
Member
For y-hangs I currently terminate the traverse line at the first y-hang bolt, take a single line down to a fusion knot with one loop kept short as a central belay loop and the long loop connecting to the second y-hang bolt. Hopefully the picture has worked.
It uses less rope than a typical bunny ears knot, still has a central belay loop, won't slip and is easy to adjust.
Can anyone tell me if there's anything wrong with this? I'm coming at it from a best practice \ instructing angle.
It uses less rope than a typical bunny ears knot, still has a central belay loop, won't slip and is easy to adjust.
Can anyone tell me if there's anything wrong with this? I'm coming at it from a best practice \ instructing angle.
christopher
New member
Well, I'm not sure those coat hangar hooks are unquestionably reliable
JasonC
Well-known member
Interesting, Jon, can't see a problem with it.
But it wouldn't work substituting your fusion knot with a bunny-ears: with the latter on both anchors of a Y-hang, the two loops will self-balance, in your set-up, I could see the little belay loop being self-balanced out of existence!
But it wouldn't work substituting your fusion knot with a bunny-ears: with the latter on both anchors of a Y-hang, the two loops will self-balance, in your set-up, I could see the little belay loop being self-balanced out of existence!
Mark Wright
Active member
Jon said:
Coming at it from a best practice / instructing angle, particularly with novices, the well established, tried and tested Fig. 8, 9, Bunny & Alpine Butterfly would definitely be the best starting point. I would consider a Fusion Knot to be a more 'advanced user' type of knot.
When you get to a pitch head you want to be able to instantly recognise that the knots and rigging are safe. If you asked 100 cavers if they recognised the correct tying of the traditional 4 above I would say at least 80% would recognise them. I bet only 10% would recognise the correct tying of a Fusion Knot.
I like to think I know a bit about knots through tying them as a major part of my job for the past 35 years and being a member of the International Guild of Knot Tyers, but I certainly wouldn't recognise the correct tying of a Fusion Knot.
I've not seen the results of any professional testing to comment on whether there's anything wrong with it in terms of the amount of strength loss, including any variations in its tying or any likely slippage in the small central loop but, in an industrial / professional novice training environment, the very fact that it is not easily recognisable would be sufficient for its use not to be considered as best practice.
If it's ever proven to be safer and over 80% of cavers can easily tie it and/or recognise it, then, with its extra (insignificant really) saving in rope, best practice could develop and see its more widespread use.
I've seen quite a few fancy cow's tail and rigging knots come and go over the years. I'll wager the Fusion Knot will be another one, with just a handful of cavers keeping them alive.
Mark
ZombieCake
Well-known member
Doesn't matter about the elegance of the embroidery, or a few newtons here or there. If it fails you're stuffed. Minimizing failure is good, I think.
andrewmcleod
Well-known member
I was unconvinced by the Fusion until I was shown how to tie a Bowline on a Bight by first tying an overhand on a bight and then reaching through the loop to grab the two new loop. The fusion is the logical extension of this, but replacing the overhand with a Fig 8.
But I was quite surprised, when messing around with rigging at Whitewalls on shiny 8mm, to see a Fusion slip quite a bit when heavily loaded sideways on the incoming traverse line. Rope was pulled from the unloaded Y-hang loop into the loaded Y-hang loop, potentially messing up your careful balancing for a clean hang. That said, I suspect a BoB/Fig 8 BE would have been worse, and I've not seen on it thicker rope.
In TobyK's example, I don't really like it because I'd not really be sure of the motivations. I wouldn't clip the little loop, even though that might reduce the fall if the right hand bolt failed, because that loop comes out of the top of the knot instead of the bottom. I think it will pull the knot in funny ways of loaded (rolling it apart). I also worry about that little loop being pulled tight (although it can't actually pull through).
But I was quite surprised, when messing around with rigging at Whitewalls on shiny 8mm, to see a Fusion slip quite a bit when heavily loaded sideways on the incoming traverse line. Rope was pulled from the unloaded Y-hang loop into the loaded Y-hang loop, potentially messing up your careful balancing for a clean hang. That said, I suspect a BoB/Fig 8 BE would have been worse, and I've not seen on it thicker rope.
In TobyK's example, I don't really like it because I'd not really be sure of the motivations. I wouldn't clip the little loop, even though that might reduce the fall if the right hand bolt failed, because that loop comes out of the top of the knot instead of the bottom. I think it will pull the knot in funny ways of loaded (rolling it apart). I also worry about that little loop being pulled tight (although it can't actually pull through).
Jon
Member
Mark Wright said:
I'm glad you commented, I value your input. I feel that the "not easy to recognise \ not in common use" arguement does have some merit in personal caving as everyone can probably rig and will be looking at the rigging and making a judgement. Although if we wait for 80% usage surely nothing will ever change?
When taking clients they won't know what they are looking at and rigging with minimal rope and loops and one easy to clip central belay loop has its advantages.
On wide y-hangs the saving in rope length over a traditional 2 loop bunny ears is helpful and it's far easier to clip into than the two loops of a bunny ears of almost any variety which also negates the need for a central "master" krab for clients to clip into.
caving_fox
Active member
Jon said:
/Not an instructor.
If I met that at a pitch head I'd be concerned. I don't like the central loop, as it's unfamiliar to me, and looks like the knot hasn't been dressed correctly. I don't like the butterfly as the 'approach' knot because it's at a strange angle (will very much depend on bolt placement), and could be very awkward to reach the rest of the traverse depending on available footing.
I'd rig it with the 'spare' loop brought up to the middle 'bolt', or if that wasn't available with two single fig8s, or most likely with a double fig8 and terminate the traverse a knot earlier - all very much depending on the actual pitch head.
Mike Hopley
New member
I can understand your motivation here, but I don't think it's a good idea. You're loading the knot in a way it's not "designed" to be loaded, and that makes its behaviour unpredictable, especially with a relatively "loose" knot such as the fusion.
The fusion has been tested plenty by the French (I believe), but not in this configuration. It's probably okay, but you'd need a lot of testing to make that "probably" into a "definitely".
If you want to keep the same setup, but without loading the knot dubiously, I'd recommend the "Diju" knot as shown in this EFS paper [PDF, page 15]. This knot is formed from a bunny-ears fig-8, with one of the loops passed underneath all three lower strands, creating a clip-in loop that loads correctly.
The Diju knot is intended for use with direct dyneema attachments, which are sometimes very difficult to clip into (e.g. a single-anchor rebelay). Using it on a Y-hang is not the intended application, but the direction of load should be okay.
