240cm Dynex/Spectra Runner as a Trad Anchor

I have a question about using a 240cm sling as a trad anchor.

There is a video on youtube that shows a quick anchor setup. Please comment as I am unclear whether this is a bad idea or not. Also my thoughts below. Please correct me if I'm wrong. This is serious shit!!

youtube.com/watch?v=P6mt0U5…

My take, but this needs testing: If you use this 3 leg anchor technique with an overhand master-point you get 50% efficiency on the sling (ie 22kN becomes 11kN in each leg). If equalized properly you will have a maximum distribution of 11kN:11kN:11kN capability. That gives you a 33kN Anchor with redundancy. A typical leader fall is between 3-7kN. So you have a 33kN anchor supporting a 7kN force. Should be OK ? Using 2 slings would give you 66kN anchor if slings are paralleled.

However to best this, take 2 separate slings of 240cm, loop through Pro points as this video shows, double 'biner the common bends (ie don't tie the overhand master-point knot but put a 'biner there instead) and you have a sliding system which has no knots, is redundant and can take 133kN. It self equalizes and it is light.

You are over thinking this.

A sewn runner is perfectly adequate as a belay anchor. I'd recommend a longer one for trad, or a web-o-lette (rabbit runner).

But your sliding knot is a terrible idea unlesss you need to move around and want to keep a bomber (meaning all 3 pieces are perfect placements in quality rock) anchor equalized.

I have no idea why you would make it doubly redundant. When you tie a masterpoint, all the loops are independent, failure would require 3 loops to fail. Creating double redundance is just dumb.

Also, is the sling really 50% in each loop? I'd think it's probably double then reduced by the knot, since the loops are independent.

Btw, are you tossing a car off the anchor with a static rope? Why do you need 133kN vs whatever the actual sling is by itself with a masterpoint knot?

So you want a system that equalises 133kN over 3 pieces? One piece that will hold 44kN is usually considered adequate.

I love my quad length runner made by Mammut. Often use it to sling big trees, as well as equalize three pieces for a trad anchor. I generally will tie an overhand master point but if I'm short on length a sliding x is fine if all your pieces are bomber. It's always going to be situational, however I find the 240cm length is great and quite useful for something that racks up around the size of a double length nylon.

Don't forget that while you're on lead every time you stop to place gear you need to place 2 pieces then place 2 quickdraws on each piece-one for each of the single rated ropes you are leading on.

So how did you come to the conclusion that your anchor is rated to 133KN? How strong do you think those cams/stoppers you built the anchor with are?

Avoiding a factor two should be a priority of the leader on the next pitch. Protecting early and often where possible.

The sling, I don't believe is the weak point. Only a handful of pieces are rated to more than 12kN, even assuming he builds his belay with three 15kN pieces, he is still limited to 15kN per leg max. Even assuming it's perfectly equalized and the worst case fall happens, I serious doubt his webbing needs to get any where near 133kN.

There's a point where people just get silly, he's hit that point.

OK so firstly a FF2 will normally create upto 7kN on a dynamic rope. Maybe 8kN. UIAA usually give 8.7kN as the maximum FWIK. 12kN would break your bones or worse and is based on the parachute testing done by the military. Hence UIAA being conservative. It is rare to have an FF2 fall with proper rope management.

As far as the sliding-x with limiters, according to Mammut on their 240cm 8mm sling pamphlet, an overhand reduces the efficiency of the sling by -54%. That means that if you make a sliding-x out of it with overhand limiter knots your sling is now only rated at 22kN * .46 = 10.12kN. So making a sliding-x with limiters will not meet your 25kN minimum recommended anchor. (BTW 25kN is the combined load capability for an equalized system and 25kN doesn't meet the 5:1 rigging safety factor). However it's a choice of 'good enough' vs 'academic'

In a single sliding-x, limiter knots weaken the system significantly and I would not trust my life to a less than 1.5x safety factor.

Now as far as tying 3 pieces of pro and using an overhand, as I said previously (11kN was the figure I used but 10.12kN is what Mammut says), in a perfectly equalized system (which is impossible with an overhand) you will have 11:11:11kN distribution [best case]. Combined = 33kN. This is probably adequate. However it doesn't equalize. So the 'zipper effect' can be an issue. The question I have about this is that is the Mammut -54% figure relevant as the bend radius of a BFK is a lot larger than a single overhand.

For a 'potentially' better system, loop a sling through the 3 bomber pro pieces and double biner the legs of the 'W' and the ends together. This will equalize and give you 22kN per leg (which is way overkill because your pieces are probably only rated to about 10kN best case). The problem is no redundancy. Hence me saying use 2 slings. Yep the system is very capable of handing big loads but you now have a really bomb-proof anchor. It's just the pro placement you need to worry about. Extension and friction is the only worry about this system - and shock-loading. With a perfectly symmetrical 'W' you'd only get 2/6 extension (ie 1/3rd) if one of the legs blow. This is where I have some reservations because a sawing action of sling on sling can be a real big issue. However the system legs are now rated at 22kN so it's unlikely that the slings would break since there is give in the system.

Yes, the anchor 'slinging' is way overkill. But removing the knots makes it safe. Knots are bad juju for dyneema/spectra. For the price of two 240cm slings which weigh practically nothing, you don't need to worry about the sling part. Pro placement is the only big concern now.

I know there was a comment, "I'm over thinking it". Actually isn't this what these forums are about ? To figure stuff out beforehand vs on the face ? If someone hadn't thought about a sliding-x and the like we'd all be using a BFK master-point still and maybe using hemp rope because no-one took time to think about nylon weaving etc for modern ropes ? :-)

J. Serpico wrote:You are over thinking this. A sewn runner is perfectly adequate as a belay anchor. I'd recommend a longer one for trad, or a web-o-lette (rabbit runner). But your sliding knot is a terrible idea unlesss you need to move around and want to keep a bomber (meaning all 3 pieces are perfect placements in quality rock) anchor equalized. I have no idea why you would make it doubly redundant. When you tie a masterpoint, all the loops are independent, failure would require 3 loops to fail. Creating double redundance is just dumb. Also, is the sling really 50% in each loop? I'd think it's probably double then reduced by the knot, since the loops are independent. Btw, are you tossing a car off the anchor with a static rope? Why do you need 133kN vs whatever the actual sling is by itself with a masterpoint knot?

OK, I now get what you are saying. You make a sliding-x with limiter knots, hence each leg is reduced to ~10kN. You have 2 legs hence you now have a 20kN anchor. Perfect. Thanks. :-)

Gaz wrote:If someone hadn't thought about a sliding-x and the like we'd all be using a BFK master-point still and maybe using hemp rope because no-one took time to think about nylon weaving etc for modern ropes ? :-)

Most people use the BFK or just the rope or something else rather than the sliding X. And they are correct.
There´s a million discussions about this already on the internet but judging by the video you linked to learning from the internet is worthless anyway however here´s my 2c worth. Several good pieces tied to you somehow is an excellent belay, more complication is rarely better.

Jim Titt wrote: Most people use the BFK or just the rope or something else rather than the sliding X. And they are correct. There´s a million discussions about this already on the internet but judging by the video you linked to learning from the internet is worthless anyway however here´s my 2c worth. Several good pieces tied to you somehow is an excellent belay, more complication is rarely better.

Yes. I've pretty much given up farting around with complicated systems. I use either the rope or, more recently because I'm almost always leading each pitch, a Belay Sling that's often prominently featured in the DAV belay setup "white papers". As usual, the Germans have a more elegant engineering solution to our 'lettes and tied off slings...

I'll keep on posting this as one of few online videos worth watching to learn something.

http://vimeo.com/47001108

That Eldrid sling so silly. When I'm multi pitch climbing with bolted anchors, I don't even need a sling for the anchor. Just clove the two bolts inline and call it good.

As for the 240cm sling, its a great length and super light. The only drawback is if you need to leave material behind for a decent it more expensive than cordelette. Plus you can untie a cord if need be.

rocknice2 wrote:That Eldrid sling so silly. When I'm multi pitch climbing with bolted anchors, I don't even need a sling for the anchor. Just clove the two bolts inline and call it good. As for the 240cm sling, its a great length and super light. The only drawback is if you need to leave material behind for a decent it more expensive than cordelette. Plus you can untie a cord if need be.

Sure, if swinging leads that will work. Not as convenient if leading each pitch and does not create as clean a power point IMO. I often go with a Fixed Point belay and the "belay loop" on the sling is easier to work with than a biner directly into a bolt. WMMV of course.

The slings are also easier to "stow" compared to a 'lette. Just like shouldering a 48in sling.

I'm not sure why the Belay Sling gets such disdain to be honest. We use purpose built devices for other aspects of our sport where a more "general" system would be arguably simpler. A Belay Device vs the Munter Hitch comes to mind. Obviously there's a balance between specialized efficiency and overall utility but I've found the distribution to be good.

OK, so we're going off topic talking about fixed bolts/hangars. For that tie a bunny ears in your rope. Hook each ear to a biner+hanger and you're done. Belay your second off the shelf. Simple, light, bomber, dynamic anchor and no mess (or extra shit to carry).

As far as the sling I'm still trending towards a BFK master-point off 3 pieces of pro. I just would like to know how one deals with directionality/proper load sharing and the fact that a BFK weakens the system (anyone have any data on this type of setup ?).

Gaz wrote: youtube.com/watch?v=P6mt0U5…

the video is pure gold, thanks for sharing. what a dork! (the car salesman in the video that is)

Drunk posting but...holy shit. Exceptional service in the national interest. Let's overdo it as usual.

Gaz wrote:UIAA usually give 8.7kN as the maximum FWIK. 12kN would break your bones or worse and is based on the parachute testing done by the military. Hence UIAA being conservative.

The UIAA (through the military) found that 12G is the maximum amount of force a human can withstand for a short period of time with no lasting injury. Also, the military's testing showed the maximum impact force a paratrooper can withstand is 12G, not 12kN. It just happens to be that 12G translates to 12kN using the weight the UIAA uses (80kg inflexible mass simulating 102kg flexible mass), but if you are not 102kg then you may be able to withstand more. And the UIAA is not being conservative, the UIAA standard allows for ropes to have impact forces up to and including 12kN. The Maximum Glider is nearly at 11kN.

If a human is willing to allow for injury, you can sustain far more than 12G. There have been records of people surviving over 200G for incredibly short periods of time. On the flip side, when placed in centrifuge gravity simulators, most people have a hard time sustaining 3G for more than 30 seconds or so, and few people can sustain 4G or more without specialized training. I have been in a centrifuge, and just 2.5G for a few minutes is a pretty annoying ride.

Gaz wrote: I just would like to know how one deals with directionality/proper load sharing and the fact that a BFK weakens the system (anyone have any data on this type of setup ?).

You guess the direction (down is good). You won´t achieve load sharing, proper or whatever so you make sure the pieces are good, they are redundantly connected and that nothing nasty happens if one or more fail. The knot strength is fundamentally irrelevant, experience tells us this is not what will kill you in the course of your climbing career.

The idea is to have 3 bomber pieces, one on each leg. Then each leg can handle a FF2 on its own. The other 2 are just redundant. If you suspect a piece may not be full strength keep adding to it until you have enough pro. Then equalize these pieces and they become only one leg in the system.

The sling is plenty strong to handle a FF2.
I don't agree with your theory that each leg will equal 11kn. The knot involves 3 legs and that gives it a lot a room to tighten and disapate energy. As long as you get the equalization close the anchor will partially distribute the load. All things considered this is as solid as it gets and has been used successfully for decades. Other systems may offer more strength but at the cost of complexity.

Rocknice2, great info thanks.

http://www.mountainproject.com/v/consensus-on-knots-in-slings/108738915__2#a_109713461

I'm sticking with 7mm cord for a few reasons. 1) Utility - I can use it for a bunch of things. 2) it's slightly dynamic, hence better energy absorption, 3) it doesn't abrade as quickly.

The utility is the main factor. Prusik, cordalette, quad, extendable (by untying the loop) etc. It's cheap. OK, not as light admittedly. I always have 60cm runners anyway so a 240cm seems to be less useful when I pair 60cm runners with a 7mm cord.

Thanks for all of your comments/thoughts. Very useful discussion. :-)

Slightly off topic rant because of the superiority of all those who use the rope for anchor. I decided this year to use the rope a few times even when I had cordellette I practice this but rarely use it in real climbing. Because you can't honestly say something is not worth it until you actually use it.

My take.

The rope is neither faster or more convenient. A cordellette should be carried anyway for self rescue. You also lose about 20ft of rope when using the rope, a occasionally that is important. And if you carry a 70m to use the rope, than you are carrying even more weight.

All things considered, it's a bullshit superiority complex some climbers have. You should be able to use the rope, and should practice it from time to time, because one of the times I used the rope, I was short a cordellette. But I think the cordellette is overall slightly superior to the rope, just like in most cases a autoblocking reverso is superior to a munter. But everyone should know how to belay off a munter.

Slightly off topic rant because of the superiority of all those who use the rope for anchor. I decided this year to use the rope a few times even when I had cordellette I practice this but rarely use it in real climbing. Because you can't honestly say something is not worth it until you actually use it.

My take.

The rope is neither faster or more convenient. A cordellette should be carried anyway for self rescue. You also lose about 20ft of rope when using the rope, a occasionally that is important. And if you carry a 70m to use the rope, than you are carrying even more weight.

All things considered, it's a bullshit superiority complex some climbers have. You should be able to use the rope, and should practice it from time to time, because one of the times I used the rope, I was short a cordellette. But I think the cordellette is overall slightly superior to the rope, just like in most cases a autoblocking reverso is superior to a munter. But everyone should know how to belay off a munter.