UKC

A bit of gear advice needed...

I've got a thin dyneema sling (8mm I think), that I have knotted at regular intervals with an overhand knot. With it being such a slim sling, the knots are actually quite small and the whole setup looks quite practical.

In fact, on the face of it, this setup looks safer than a daisy chain as each loop should take a greater than 2kN breaking force. I know that knots reduce the strength of a sling, but even by 50%, my 22kN sling with several knots in should be able to take 11kN right?

Am I missing something or is this actually an OK thing to do?

Thanks

In reply to BStar:

http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

In reply to BStar:

While this does have better pocket strength than a sewn daisychain, i would be wary of using dyneema. Firstly it doesnt hold knots well (being slippery) and the overhands are liable to roll under load. Secondly, as dyneema is super-static, it is very vulnerable to shock-loaded failure, so if you took even a moderate fall onto your 'daisychain' directly clipped into gear, its overall breaking load could be exceeded (and it would likely break at a knot) . Nylon would be more suitable for this setup, if you really want to use it.
Also, from experience, unless you cunningly tie offset knots to create loops left and right, the chain will be very difficult to clip into under load as all the pockets will close up.

In reply to Dr Toph:

Cheers for your reply, you raise some good points.

I was aware about knot rolling but discounted this as they would have to roll a long way and past other knots (unless it was the end knot) to become unsafe. Clipping the end loop (exactly what not to do on a DC) as well would prevent a knot rolling off the end.

You are right about shock loads though, probably more of a problem if aiding rather than weighting a belay stance with it.

I hadn't thought about not being able to clip under load, good point!

In reply to BStar:

What is it that your using it for?

In reply to BStar: I would say shock loading at a belay is you primary concern as its not uncommon to move up to adjust a knot or use it for abseiling and use it as your primary attatchment. Just not a particularly good idea. Somewhere floating around there is an ENSA video about rope lanyards which is faily enlightening too. Rope is a far better idea, and Petzl now have a sewn rope lanyard with an adjustable clip in point... Take a look. I know it means spending money but this is going to be your main connection to the cliff at times...

In reply to BStar:

In my opinion and experience you want one of a number of items available which have come to be known as "personal anchor systems". I prefer the Sterling Ropes Chain Reactor as it's made of nylon not dyneema, and so is theoretically better dynamically, and it's also softer and "hangs" better when not in use. The Metolius P.A.S. is popular (dyneema) and I believe the Grivel equivalent purports to be a dyneema/nylon mix. As soon as you see the illustrations I think you'll know it's what you've been looking for. Here are links to each of 'em.

http://www.amazon.com/Sterling-Chain-Reactor-Pro/dp/B007NVN2T0/ref=pd_sim_4...

http://www.rockrun.com/metolius-pas-22-with-krab?gclid=COnMsvCUhssCFW8o0wod...

http://www.outdoorgb.com/p/grivel_daisy_chain_slings/?utm_source=froogle&am...

In reply to BStar:

There are several better alternatives available. The Petzl one mentioned above, the Grivel Daisy Chain, one made by Beal and one made by Metolious. These are the ones I know of that are all fully rated, there may well be others. The problem is they are all quite bulky and something else to carry. With double ropes you are far better off just using the rope although I have used the Grivel Daisy Chain when ice climbing as it makes equalising the screws a doddle when used in combination with a direct belay.

Al

In reply to deacondeacon:

There's an aid route that I would like to do, but as I have never done any aiding and probably won't do much more I am not going to spend lots of money on lots of new gear. Plus, when I was in Cogne this winter, I saw lots of people using lanyards to clip themselves into the bolted belays, it looked like a quick way of doing things.

beardy mike, I'll take a look at the petzl thing. This video is a good one to watch, not sure if it's the same one you were talking about... http://www.beontherope.com/en/2016/01/study-lanyards-for-climbing-and-mount...

In reply to BStar:

You'll never get the knots out once you've aided on it. It's safe enough, just form the loops carefully so they stay open under load. Or buy one so you don't wreck your sling. It's never the only thing between you and the floor if you're doing it right.
Jk

In reply to BStar:

https://youtu.be/DpWKrghSLao?t=5m5s

I think this is the relevant bit of the ENSA video for anyone interested in using the type of lanyard your describing.

In reply to BStar:
I had a play around with a Purcell Prussik recently.
It seems a very clever thing. Does not seem to like factor 2 falls but has lots the adjust-ability, cheap and multi-purpose.
Looked a good thing for clipping in to anchors or clipping an 'I'm feart' screw in winter.

*prepares for flaming*

In reply to Hay:

They are a bit bulky compared to sewn loops, but as you say, cheap and effective.

Good info here: http://www.bluugnome.com/cyn_how-to/gear/purcell-prusik/purcell-prusik-teth...

In reply to Hay:

Fascinating. You could just use your ab tat for the PP and then it's to hand if you need it to revert to being tat. I like the look of that, seems to be an acknowledged and accepted tool in SAR operations, but handy all day long as an adjustable cow's tail.

In reply to BStar:

https://www.petzl.com/GB/en/Sport/Lanyards/DUAL-CONNECT-ADJUST
https://www.petzl.com/GB/en/Sport/Lanyards/CONNECT-ADJUST#.VsiuqfmLSUk

I saw both of these at Fred outdoor show and ISPO and they are really good pieces of kit. Easy to adjust and dynamic. Nylon sling whilst it's more dynamic than Dyneema, you still don't want to be shock loading it. But all this said, for an aid route, a knotted sling will be fine. You're only using it for progression. However, from personal experience, if you're aiding a roof for shits and giggles, the best bet is an easily releasable lanyard. Daisy's are fine on vertical terrain, especially in conjuction with a fifi hook. If you are on a big overhang, only have a daisy and are clipping it with a carabiner you will soon lose the will to live. A fifi with a pull chord threaded through the hole at the top is infinitely better on this terrain. But the very best for that sort of thing is an easily releasable adjustable daisy like the Yates daisy. http://yatesgear.com/climbing/etriers/
If its just for aid, and you're only doing it once, and you're careful not to shock load it and you're backed up by a lead rope, then go down to halfords, by a camlock roofrack strap, preferably two, cut to length and tie a couple of loops and you're going to be in a much better situation than a home made standard daisy... but all the usual chris tan death mods apply <cackles>.