Preventing the sling from unclipping from the biner

Not to beat a dead horse, but for those who may be reading this thread and not know the background. As I understand it:

The danger of knotting dyneema arises in its 'ultra-static' like loading. It does not give so think of it like a steel cable but less durable. The danger of knotting it is intensified when the turning radius of the material is shortened. This is how all knots very in reducing the strength of a material. The figure eight is a great knot because of its great turning radius. Therefore knotting the dyneema upon itself (overhand) will always be more dangerous than hitching it around an object (clove hitch). Apply this knowledge to all things climbing. Dyneema's ultra static characteristic is more dangerous because of the tendency to cut itself in a tightly knotted (short turning radius) precedent.

Hope I explained correctly, that's all...

reboot wrote: That's the impact force of the climber, not the sling/pro, which is much higher (not quite double). Still, 14KN is higher than the rating of most smallish pro. But add in some wear & tear, the margin isn't terribly large anymore.

fair point ... forgot the pulley effect ... brain fart

but honestly if yr seeing that much force on a fall yr seriously screwed IMO, especially cragging

your belay device (atc, smart, mega jul) will start seeing serious slippage before that point

not to mention that ropes even when new will barely take that in a static pull test ...

BD QC lab

blackdiamondequipment.com/e…

also ...

Chris Harmston, Black Diamond's Quality Assurance Manager, has reviewed field failures of climbing gear for eight years. He has never seen a stopper rated at over 10 kN fail, and has seen only a few carabiners fail in closedgate mode. He believes that forces exceeding 10kN rarely happen in climbing falls.


caves.org/section/vertical/…

and

How strong does your climbing gear need to be? BMC

http://files.meetup.com/1324053/How_strong_does_your_climbing_gear_need_to_be(0).pdf

i would worry much more about a skinny sling getting cut than it breaking with rope in the system

if knots on dyneema with rope in the system concern you, simply use one of the other full strength possible solutions

I have a feeling this is a stupid question, but any recommendations for the type of tape to use, or not use.

I think taping the rope end makes most sense, gives most flexibility (while remaining full strength).

Thanks for some great information, especially Bearbreeder.

J. Serpico wrote:I have a feeling this is a stupid question, but any recommendations for the type of tape to use, or not use. I think taping the rope end makes most sense, gives most flexibility (while remaining full strength). Thanks for some great information, especially Bearbreeder.

i use this to mark my soft goods (they say its just electrical tape) ... you can find other stuff out there at any climbing store ... just make sure its non-corrosive

mec.ca/product/5011-923/can…

reapply the tape and resinspect it every now and then (also under the tape)

if you do use a rubber band/keeper below the tape (without the band/keeper the sling can still slide off the biner, just less likely to do so IMO than an open sling), remember that if the tape comes off the "rubber keeper" failure scenario is much more likely again

edit to add .. see my addition below ... i dont recommend the tape method

tape + elastic to fix into place (not recommended)

bearbreeder,

Good information. Thanks for starting this thread. The photos help.

just to add ... dont let this happen ... hopefully itll be pretty obvious when you extend and clip it

with the clove/overhand this is not a concern

DONT let this happen ... should be pretty obvious

edit ...

ive thought about it abit and while im fine personally taping up the sling and using it myself, if someone else uses your gear they might not recognize this kind of loading ...

im not going to recommend it ... ill edit the post to reflect this ...

Why not just use nylon? Then you can fix the biner with an overhand or fig 8 and then the knot will absorb almost as much force as you lose strength? Or am I missing something again?

Nylon extendable draws

Thanks for the contributions. The pulley effect is no minor detail and deserves attention.

Also, do the laws of physics change when doing multi pitch vs cragging? Hmm.

The accident that brought about this discussion took place while cragging.

eli poss wrote:Why not just use nylon? Then you can fix the biner with an overhand or fig 8 and then the knot will absorb almost as much force as you lose strength? Or am I missing something again?

Tighten that knot! ...and get a mentor for real.

Has anybody contacted Mammut? I would like to hear what a manufacturer would say about this. I can hardly imagine the scenario of the sling cutting itself in a knot. In case of a fall the rope should absorb quite a bit of the shock. Has anybody girth hitched 2 dynema slings together for slinging rocks etc?

bearbreeder wrote:just to add ... dont let this happen ... hopefully itll be pretty obvious when you extend and clip it with the clove/overhand this is not a concern edit ... ive thought about it abit and while im fine personally taping up the sling and using it myself, if someone else uses your gear they might not recognize this kind of loading ... im not going to recommend it ... ill edit the post to reflect this ...

Nope no tape for me! Except on my hands...

Really good info here! Bearbreeder knows his shit!
Ye cragging or multi pitch you can get hurt just the same. Except maybe in multi pitch there is more rope drag and you have to use slings to extend more then just a straight crag line. More overhangs and traverses in multi pitch generally.

Everyone should watch the DMM videos on breaking dyneema slings. And then after you're scared you should go read the thread "Am I a Steel Boat Anchor". Well actually I'm not sure that thread says anything of any value, but it is a good analogy.

http://vimeo.com/27293337

Steve Levin wrote:This: (LOCKING CARABINER PICTURE)

A locker on every draw on a 50+ meter pitch? I think safety is important, but who is really going to do this?

i have a couple setups that i use with locking draws. one has a locker on the bolt end and a wiregate on the rope end (for sport climbing where there is hard climbing and something going wrong would be real bad, but i need to be able to clip the rope quickly). i also have a couple sport draws with lockers on both ends for times when i can clip from an easy stance, but the climbing above is hard and something going wrong would be real bad. usually in my sport pack i have 2 of each types.

i also have a couple slings set up with double lockers for the same scenario on gear routes. it works well if you can get a good stance for futzing with gear and the lockers, but if you are in the middle of a gunfight it is kind of tough.

What about auto locking lockers? Does anybody make a small one of those?

CJC wrote:From the BD link in Jakes's post ^^^ "Dyneema/Spectra doesn't hold a knot. Never use a knot with Dyneema/Spectra."

This is intended to dissuade people from tying straight dyneema into runners like we all did for decades with 1" tubular and later 11/16" tubular nylon. It has nothing to do with the knot discussion in this thread.

Joan Lee wrote:What about auto locking lockers? Does anybody make a small one of those?

Maybe the biwire would help?

backcountrygear.com/rockd-b…

Biwire

Joan Lee wrote:What about auto locking lockers? Does anybody make a small one of those?

i find autolockers more difficult to use for this type of thing. that being said, i have never really been a fan of them so i never got used to using them in general.

Dylan B. wrote:With C4s, would you consider using an alpine draw by basket hitching the sling through the thumb loop, and then using the two wiregates opposite and opposed on the rope?

Not recommended. The thumb loop deforms when loaded and can cut dyneema which is why BD uses a doubled up nylon sling and DMM abandoned the thumb loop altogether when developing the dragon cams.