Do most people rig Y hangs with two loops

[Stu]

... the key point is surely that there are a number of ways of doing things, some of which have advantages and some of which have disadvantages. It's the job of the rigger to balance these up and decide what to do.

... its generally best to avoid the ones with disadvantages

But they all do have disadvantages Cave Mapper. Example: people using Alpine Butterflies in the system where a better knot would be a Fig 8 loop. Why would it be better? Because the F8 loop is an end loop knot and very strong when orientated as such. Whereas the AB used as an end loop knot is less strong than the F8 loop. For every plus there is a negative.

For what it's worth Alan Warild says in his Vertical manual the one knot that should be learnt if only one knot is learnt, is the F8 loop.

 

[dunc]

For what it's worth Alan Warild says in his Vertical manual the one knot that should be learnt if only one knot is learnt, is the F8 loop.

I'm sorry, but I hate it when 'manuals' 'guides' or whatever you will use this cop-out. I'm no rigging/vertical/knot expert but only one knot?? You should be capable of learning, remembering and have the ability to use more than one knot (a couple is a good start) - I'd be concerned/worried if I went caving with someone that rigged (random example) Rowten Pot entirely on F8-loops.. 

 

[ianball11]

3) as a last resort, an actual P hanger of any design as this would have no redundancy and as mentioned no shock loading assistance if I slipped. 

If a traverse line is say 150mm lower than a bolt, a slip onto a cowstail is stopped 15cm sooner and so I'll be travelling a bit slower too, and the bolt is stronger than the rope(?).  Though a dodgy spit would be a different matter.
[cowstail knot relaxing anyone?]

 

[Stu]

For what it's worth Alan Warild says in his Vertical manual the one knot that should be learnt if only one knot is learnt, is the F8 loop.

I'm sorry, but I hate it when 'manuals' 'guides' or whatever you will use this cop-out. I'm no rigging/vertical/knot expert but only one knot?? You should be capable of learning, remembering and have the ability to use more than one knot (a couple is a good start) - I'd be concerned/worried if I went caving with someone that rigged (random example) Rowten Pot entirely on F8-loops.. 

Reread it. He's not saying only learn one knot. He's saying if you only ever learnt one knot, this one would cover it. To be fair Warild isn't a punter...

As for rigging with just F8 loops: nothing wrong with it per se. There is a certain myth or misunderstanding about the Alpine Butterfly. It's major feature is that when the two standing parts of the rope are pulled apart, it doesn't deform. When placed in a Y hang as the last knot, the standing parts are not in alignment. Test data suggests that in this form it's no stronger than if a F8 loop was used. The problem with a F8 loop is if its anchor pops... then it might deform.

Actually there is something wrong... we've gone massively off topic.

 

[mikem]

The threads wouldn't be so interesting to read & you wouldn't learn half as much if they stayed on topic...

Mike

 

[ianball11]

Personally my preference is
1) clip into the rope loops <snip>
2) line, <snip>
3) as a last resort, an actual P hanger <snip>

I agree with this too.

Eek, Damian and Geoff says loops rather than bolts, I must be wrong there then! Seems counter intuitive to opt to fall further than shorter if the slip did happen.

 

[mikem]

Clipping to the bolt means falling less far provided the bolt holds, but what happens if it (or the rock around it) fails? This is a more likely scenario than the rope failing and would result in (hopefully) you shock loading your other cowstail, or the other anchor (depending which comes tight first), or worst case finding you're not attached to anything...

If you are clipped to two points you are less likely to shock load the system, although a traverse line to a single bolt will still mean you drop quite a distance if that end bolt fails (& if you can only clip to the traverse line, as bolts are too far apart, the possibility of the krabs sliding down the rope and over the end knot), so maybe alpine butterflies should be used along the rope as attachment points (or bolters consider whether more bolts are required, depending on the likelihood of someone slipping off the traverse.

Mike

 

[ianball11]

I appreciate all of that, and totally agree on a spit, where you've no real idea how old it is or who placed it and it's not as highly rated as a pbolt, but would you expect a high probability of a pbolt and rock it's drilled into to fail from one slip onto a cowstail? 
Though there could be hundreds of slips onto cowstails in the past I suppose.

I'm learning here 

I think the answer is to follow the knot loop clipping convention, though I might make myself feel at ease by shortening the length of my cowstails 

Although on a different notion, clipping my metal cowstail karabiners into the metal bolts would wear them out maybe faster than clipping into the rope attached to it, hmm.  I know pull through bolts are given a sacrificial maillon in places but a gritty rope be dragged for meters would be worse than an alloy or steel karabiner clipped in, hopefully without being weighted.

 

[mikem]

Slipping whilst clipped into the bolts could also damage the bolt to the point where it might cut through a rope, there was a recent climbing accident where a sharp edge on a krab (I believe caused by using the end that was normally clipped into bolts) cut through the rope during a fall.

Mike

 

[Fulk]

ianball11:

Although on a different notion, clipping my metal cowstail karabiners into the metal bolts would wear them out maybe faster than clipping into the rope attached to it, hmm.  I know pull through bolts are given a sacrificial maillon in places but a gritty rope be dragged for meters would be worse than an alloy or steel karabiner clipped in, hopefully without being weighted.

I don't really see why simply clipping a krab into a bolt would cause much wear; and why would a (steel) MR be worn worse than a steel krab when a rope is dragged through it?

 

[Stu]

Slipping whilst clipped into the bolts could also damage the bolt to the point where it might cut through a rope, there was a recent climbing accident where a sharp edge on a krab (I believe caused by using the end that was normally clipped into bolts) cut through the rope during a fall.

Mike

http://www.blackdiamondequipment.com/en-us/journal/climb//qc-lab-dangers-of-rope-worn-carabiners

 

[ianball11]

I don't really see why simply clipping a krab into a bolt would cause much wear; and why would a (steel) MR be worn worse than a steel krab when a rope is dragged through it?

Fulk, I don't think we're on the same page , Hang on a mo:

http://ukcaving.com/board/index.php?topic=4234.msg60171#msg60171

these are normally installed in places where people like to do pull throughs.
If you thread the rope through the P hanger directly and frequently pull it through, then you can quickly wear out the P hanger.
the first cunning plan was to put a large maillion on the PHangers, this would wear out and be easily replaced. sadly they kept being "removed" so now we're on to a steel ring hung from 2 Phangers

So I was saying that there are occasions when us cavers have tried to reduce wear on pbolts, though in the case of giants, it is often used as a belaying pitch for lowering as opposed to abseil so the wear is greater.

So I was asking does clipping (any metal karabiner) into the bolt wear the bolt more quickly in general use than clipping into the rope knot attached to the pbolt?
Probably not a lot but over time?
Have I got my question across a better way now?  alloy or steel didn't really feature, but I was going to say wouldn't a stainless pbolt be harder than an alloy krab or steel one?  But then I thought I'll quickly have a google search so I'm not saying something stupid, but left the alloy or steel in just to confuse things!  :-\  must have been a senior moment.

 

[ianball11]

Slipping whilst clipped into the bolts could also damage the bolt to the point where it might cut through a rope, there was a recent climbing accident where a sharp edge on a krab (I believe caused by using the end that was normally clipped into bolts) cut through the rope during a fall.

Mike

Would the hardness of metals have any impact on this?  I have alloy cowstails and pbolts are 316 stainless I think?