Dyneema sling as anchor?

Harumpfster Boondoggle wrote: We are just making a case for ideal technique but that is always going to be dependent on what placements one has to work with.

This is mostly true, though I have a different view of ideal technique when the anchor placements seem bomber, i.e., most of the time for most of us. I'm a big proponent of competent climbers following on a toprope solo setup, and this is usually best to do with an anchor that does not use the rope in its construction.

Harumpfster Boondoggle wrote:

There are plenty of shitty anchors out there either by noob failure or through no fault of the climber ie nothing better available.

I think we agree. A shitty anchor is a shitty anchor whether you lace it together with dyneema or a climbing rope.

Word has it that Metolius is coming out with slings made out of dynamnic rope. Maybe that will be the best of both worlds.

Question to all:

Before one ties into the rope with a figure eight, why not:
First - thread a quick link with the rope
Second - tie a barrel not at the end of the rope

Third - tie-in with a figure eight as normal but leave a tail of rope long enough to pass around your waste with quick link against the barrel knot
Fourth - with a carabiner clip the quick link to the belay loop. 
That way when one arrives at the anchors one has  a dynamic lanyard ready to clip to the anchor. 
I have not tried this. Generally, I use a dynema sling as PAS.  But I am becoming more convinced that I should use a  dynamic lanyard.  I already carry a quick link to facilitate bailing by rappelling.  I also already carry four locking carabiners. 
(If your first thought is to tell me how stupid I am for asking, Please save the abuse and just explain what is stupid. )

Live Perched wrote: Question to all:

Before one ties into the rope with a figure eight, why not:
First - thread a quick link with the rope
Second - tie a barrel not at the end of the rope
Third - tie-in with a figure eight as normal but leave a tail of rope long enough to pass around your waste with quick link against the barrel knot
Fourth - with a carabiner clip the quick link to the belay loop. 
That way when one arrives at the anchors one has  a dynamic lanyard ready to clip to the anchor. 
I have not tried this. Generally, I use a dynema sling as PAS.  But I am becoming more convinced that I should use a  dynamic lanyard.  I already carry a quick link to facilitate bailing by rappelling.  I also already carry four locking carabiners. 
(If your first thought is to tell me how stupid I am for asking, Please save the abuse and just explain what is stupid. )

In climbing, there are lots of solutions and methods to solve problems that reduce risk or provide some benefit. While what you describe might work, simply tethering into the anchor with a clove hitch using the climbing rope is much simpler, yields great adjustability, and is commonplace.

The more 'normal' your day-to-day procedures are, the more likely your partners will be to spot errors. (Great reason to tie-in with a figure 8 vs other knots etc. ).

Keep it Simple. Keep it safe.

Seems overly complicated, Live Perched. Why not just clove into your anchor with the rope? 

David Van Parys wrote: I was told not to use it as an anchor because dyneema can cut thru nylon and since the belay loop is made of nylon it could eventually wear through

This bit of FUD generally comes from the one dude who ended up dying in Yosemite while jugging up big walls on his PAS.  He had damaged the belay loop after doing this over and over and had been warned by several partners that he needed to replace his harness due to the damage. He ignored this advice and eventually cut through his belay loop. This is led to an overreaction of people putting their PAS through hardpoints or refusing to connect dyneema their harness at all. Unless you are repeatedly sawing on your belay loop by jugging up a big wall this is not a big risk. a person who uses their personal anchor to clean sport routes or teather on a multi-pitch it's going to have to replace their harness due to the age of the nylon before they wear through their belay loop imo.  A sandy rope that you tie in with is likely infinitely more abrasive than a PAS anyways.  Just inspect your gear regularly.

Señor Arroz wrote:

Maybe I'm not understanding what you're describing, but if the leader leaves a belay and falls, isn't it the dynamic rope that's catching him or her? What's between the belay device and the anchor pieces is barely a factor at that point. Yes, it's a FF2, which isn't good, but the rope is what absorbs the shock. 

Kind of. In high factor falls, anchors made with the dynamic climbing rope resulted in lower impact forces compared to cordallete or dyneema. Relative to the entire load, it's not huge but 1 or 2 kN lower forces is pretty good. 

Harumpfster Boondoggle wrote:

@Kyle: yea go review the DMM vids ffs. Its not complicated.

I am not aware of any DMM videos that test large fall factors, when the load is connected to the anchor with a dynamic element such as the rope.  A system constructed as such will behave significantly differently than dropping a load directly onto the anchor without the dynamic element, and the resultant forces will be very different.  You cannot extrapolate the results of a non-dynamic test system to a dynamic one.

If there is a DMM video showing data to back up your claim, instead of being snarky, why not just copy and paste the link?

Señor Arroz wrote:

Maybe I'm not understanding what you're describing, but if the leader leaves a belay and falls, isn't it the dynamic rope that's catching him or her? What's between the belay device and the anchor pieces is barely a factor at that point. Yes, it's a FF2, which isn't good, but the rope is what absorbs the shock. 

Yes, the dynamic rope is absorbing much of the force, but as Harumpfster mentioned, that force has to go somewhere.  Depending on the belay stance, that might be onto the anchor.  To be clear, I don't think this is nearly enough to break a dyneema sling.  My concern was more for the forces being exerted on the belayer in what would likely be a rather violent catch.  As a belayer, I would much rather be on a dynamic anchor than a dyneema anchor in such a case.

Of course, this is why the leader shouldn't fall in that scenario.  I use dyneema all the time, including for multi-pitch.  But I am aware that this is, at least in my book, a weakness for the material.

Zack Robinson wrote:

Yes, the dynamic rope is absorbing much of the force, but as Harumpfster mentioned, that force has to go somewhere.  Depending on the belay stance, that might be onto the anchor. 

For the purposes of our discussion (breaking slings) peak impact force is all that matters.  The fact that the force eventually ends up the anchor is basically irrelevant.  Dynamic materials decrease peak force by spreading the force out over time.

Nick B wrote:
For the purposes of our discussion (breaking slings) peak impact force is all that matters.  The fact that the force eventually ends up the anchor is basically irrelevant.  Dynamic materials decrease peak force by spreading the force out over time.

But I clearly said I wasn't concerned about the sling breaking:

Zack Robinson wrote:To be clear, I don't think this is nearly enough to break a dyneema sling.  My concern was more for the forces being exerted on the belayer in what would likely be a rather violent catch.  

You did and I should have included that you made a reasonable overall point. Sry!

Single sample test, useless data, ignore these numbers, etc, etc.

I just dropped a 100kg mass on 1m of dynamic rope attached to a sewn Dyneema sling (10mm) and a tied Nylon sling (1" tubular). The test mass was raised 0.5m and dropped (so a fall factor 1, ignoring the anchor sling). All knots were pre-weighted with 100kg.

The anchor saw 6.05kN when using a tied Nylon sling, and 6.33kN when using a sewn Dyneema sling.

I think there's a negligible enough difference there. As long as there's dynamic rope in your system, you're probably as good as you're going to get. Note that there was no belay device involved in this test, so that'll reduce forces even more. Make anchors out of Nylon, Dyneema, steel, whatever - just try to attach yourself to said anchor with dynamic rope.

Zephyr Feryok wrote: Single sample test, useless data, ignore these numbers, etc, etc.

I just dropped a 100kg mass on 1m of dynamic rope attached to a sewn Dyneema sling (10mm) and a tied Nylon sling (1" tubular). The test mass was raised 0.5m and dropped (so a fall factor 1, ignoring the anchor sling). All knots were pre-weighted with 100kg.

The anchor saw 6.05kN when using a tied Nylon sling, and 6.33kN when using a sewn Dyneema sling.

I think there's a negligible enough difference there. As long as there's dynamic rope in your system, you're probably as good as you're going to get. Note that there was no belay device involved in this test, so that'll reduce forces even more. Make anchors out of Nylon, Dyneema, steel, whatever - just try to attach yourself to said anchor with dynamic rope.

Tie that anchor together with dynamic rope and do your drop and you should get results like DMM that cut in half that impact force.

A 50% reduction is good for everyone and everything involved as long as the stretch is acceptable ie no ledge to hit.

Zephyr Feryok wrote: Single sample test, useless data, ignore these numbers, etc, etc.

I just dropped a 100kg mass on 1m of dynamic rope attached to a sewn Dyneema sling (10mm) and a tied Nylon sling (1" tubular). The test mass was raised 0.5m and dropped (so a fall factor 1, ignoring the anchor sling). All knots were pre-weighted with 100kg.

The anchor saw 6.05kN when using a tied Nylon sling, and 6.33kN when using a sewn Dyneema sling.

I think there's a negligible enough difference there. As long as there's dynamic rope in your system, you're probably as good as you're going to get. Note that there was no belay device involved in this test, so that'll reduce forces even more. Make anchors out of Nylon, Dyneema, steel, whatever - just try to attach yourself to said anchor with dynamic rope.

6kN is probably not going to break most climbing gear, but I get the feeling that it's still going to hurt. And I bet it would hurt less if you were catching a FF1 when tethered in with the climbing rope. 

Tie that anchor together with dynamic rope and do your drop and you should get results like DMM that cut in half that impact force.
A 50% reduction is good for everyone and everything involved as long as the stretch is acceptable ie no ledge to hit.

6kN is probably not going to break most climbing gear, but I get the feeling that it's still going to hurt. And I bet it would hurt less if you were catching a FF1 when tethered in with the climbing rope.

Maybe I wasn't clear enough. That drop was on 1 meter of dynamic rope which was attached to a sling (one drop with Dyneema, one with Nylon). The point is that it doesn't matter what your anchor is constructed from as long as you're tethered with a dynamic rope.

Zephyr Feryok wrote: Maybe I wasn't clear enough. That drop was on 1 meter of dynamic rope which was attached to a sling (one drop with Dyneema, one with Nylon). The point is that it doesn't matter what your anchor is constructed from as long as you're tethered with a dynamic rope.

No it does matter. The forces are that much less if the anchor is built from dynamic rope effectively reducing the fall factor by having a greater length of rope present to absorb energy.

Test it?

Zephyr Feryok wrote: Maybe I wasn't clear enough. That drop was on 1 meter of dynamic rope which was attached to a sling (one drop with Dyneema, one with Nylon). The point is that it doesn't matter what your anchor is constructed from as long as you're tethered with a dynamic rope.

Sure this works on low factors falls. Because it's a low factor fall, the climbing rope isn't being stressed all that much and can take care of the the majority of the force of the fall. But in a high factor fall, that rope that's in the belay system is very overwhelmed because it's being asked to dissipate a ton of energy without a whole lot of length to stretch.

In low fall factor situations, the difference in peak load on applied to the anchor between rope anchors vs cordalette or dyneema is pretty small and insignificant compared to the system as a whole. In a high factor fall, the difference still isn't super significant relative the system as a whole, but since our numbers are bigger for the system as a whole, so is the difference in peak load between rope anchors and cordalette/sling anchors. Like a kN or 2 lower for rope anchors. 

Trigger warning: The DMM Video
https://dmmclimbing.com/Knowledge/June-2010/How-to-Break-Nylon-Dyneema%C2%AE-Slings

The issue is not that you absolutely can't use dyneema for a personal anchor, its that knotted dyneema that is then shock loaded can break. It is my understanding that this has nothing to do with the 22kn rating and everything to do with the heat produced as the knot tensions under pressure.  Anyway, this dude asked about it, so there is the answer. I also have no idea what 50% of the people on this thread are even talking about anymore.