HowNot2 Gets Closer to Reality

Drop rig created, cool!, but then he uses a 12mm static rope for the tests?! 

Easiest way to generate high loads to break everything

They are not testing the rope. They are testing the break strength of the carabiners. Trying to break them. They should probably use steel cable. 

anonymous coward wrote:

They are not testing the rope. They are testing the break strength of the carabiners. Trying to break them. They should probably use steel cable. 

Break strength means nothing in the incorrect context. "Don't cross load biners", we already know this. 

I think with a realistic setup we will see it's very hard to break a carabiner.

we will see it's very hard to break a carabiner.

Did you watch the whole video? Because that is effectively the conclusion they came to even with the static line. Well at least in that part of the system, they broke two steel carabiners that weren't supposed to be breaking due to gate loading.

Tradiban wrote:

Break strength means nothing in the incorrect context. "Don't cross load biners", we already know this. 

I think with a realistic setup we will see it's very hard to break a carabiner.

That is literally the entire point of the break test videos. It’s quite a cool series. We all know it’s hard to break our gear. They set out to determine “how hard is it?” Then they intentionally isolate one piece and see what kind of forces that piece can hold. And then they often set the system up in ways that we are taught are dangerous to see how that affects the system. I.e. cross-loading carabiners, using large angles on anchors and such.

The videos wouldn’t be interesting if they all resolved with “carabiners don’t break under normal loads”

Clearly they missed something with their set-up.

As some suggested, the quick link could move in the test. 

I pointed out that in a real fall the rope rubbing through the bottom biner in the top piece can cause vibration. 

I think the test would be more meaninful with a dynamic rope tied off at the ground and the quick link against a flat surface. 

At first I thought he was sort of wacky but I’m enjoying his recent vids. 

Mark Hudon wrote:

At first I thought he was sort of wacky but I’m enjoying his recent vids. 

To be fair, one can be wacky and accurate simultaneously.

Also i just noticed the size of the quick link in the test was 3/8 or larger.

Most bail links are 5/16.

anonymous coward wrote:

That is literally the entire point of the break test videos. It’s quite a cool series. We all know it’s hard to break our gear. They set out to determine “how hard is it?” Then they intentionally isolate one piece and see what kind of forces that piece can hold. And then they often set the system up in ways that we are taught are dangerous to see how that affects the system. I.e. cross-loading carabiners, using large angles on anchors and such.

The videos wouldn’t be interesting if they all resolved with “carabiners don’t break under normal loads”

It's just "break stuff" and fearmongering until the results can be applied to real life.

Actually i think most of their testing is the opposite of fearmongering. 

Their titles are often click bait.  But Results show stuff that doesnt make me concerned about gear.

In this case they were trying to reproduce a failure that happened in a normal fall. They were not successful. 

timothy fisher wrote:

In this case they were trying to reproduce a failure that happened in a normal fall. They were not successful. 

It’s interesting that after all their efforts to make that biner break Ryan still went on about how you shouldn’t do that. 

timothy fisher wrote:

Actually i think most of their testing is the opposite of fearmongering. 

Their titles are often click bait.  But Results show stuff that doesnt make me concerned about gear.

In this case they were trying to reproduce a failure that happened in a normal fall. They were not successful. 

Right, a "normal fall" with a static rope! That's not normal. The results mean nothing unless it's a realistic test. Maybe a dynamic rope could make conditions worse somehow, we don't know, so why not try it? Because that would be boring, eh?

Real science is mostly boring and not suitable for YT apparently.

Tradiban wrote:

Right, a "normal fall" with a static rope! That's not normal. The results mean nothing unless it's a realistic test. Maybe a dynamic rope could make conditions worse somehow, we don't know, so why not try it? Because that would be boring, eh?

Real science is mostly boring and not suitable for YT apparently.

Maybe you misunderstand the point of the testing. If you want to see the weight at which something breaks, you need to apply a force which will make it break. The strain guages will measure the force applied to the carabiner. Does it matter what the rope attached is as long as the force applied to the carabiner exceeds it's breaking strain at some point?

The only variable a dynamic rope would change would be the rate of force development. As they've already tested the slow end of the RoFD, it makes sense to test the fast end of RoFD. If they're both the same, it's unlikely that a slightly slower RoFD would be different. If they're different, the likelihood is that the RoFD varies in some linear fashion. You might then suggest that a single test would be appropriate to model a slightly slower RoFD but still in the millisecond range but the results from a static rope test still provide an excellent limit test of the RoFD variable.

None of this is "real" science, they're using what they have to roughly test a hypothesis using n=1. In this case the hypothesis is that a high enough load to a biner clipped in a particular way is enough to break it. Using a static rope gives a "worst case" loading and it still didn't break.

There's also a good chance that they just don't have enough height on the drop tower to use a dynamic rope. See how high above the anchor they needed to lift the weights even with a static line, only to generate <20kn?

Also I wonder if even with their sample rate if they're missing peak forces.

Mark Hudon wrote:

It’s interesting that after all their efforts to make that biner break Ryan still went on about how you shouldn’t do that. 

If four people survive four car crashes unharmed, would you suggest it's safe to crash cars? Hmm.

I suspect, just like when rope freakily comes unclipped from carabiners because of gate bounce, there is something situational and rare about carabiner breaking in these situations. We know that we can make the situation safer by doing something simple - why would you not recommend it?

Tim Parkin wrote:

Maybe you misunderstand the point of the testing. If you want to see the weight at which something breaks, you need to apply a force which will make it break. The strain guages will measure the force applied to the carabiner. Does it matter what the rope attached is as long as the force applied to the carabiner exceeds it's breaking strain at some point?

It doesn't matter at which "weight" something breaks, gear is already tested and stamped with that and we only need to know what "weight" to the point of a fat 50 year old man taking a whip.

What I'm saying is, try to break a biner with a realistic set up, then we would learn something. Likely Big Red is right, the rig isn't tall enough.

Tim Parkin wrote:

If four people survive four car crashes unharmed, would you suggest it's safe to crash cars?

Yes.

Just like Covid has a 99% survival rate, which means I can ignore it completely because basically no one dies from it.

In the video where the climber falls and his carabiner broke I would imagine either;

It cross-loaded and snapped. (usually unlikely due to the keeper, but I have seen carabiners get stuck in all kinds of weird ways on bolts) 

The slabby angle of the bolt exaggerated the forces of the top carabiner over the bottom bail 'biner.  In Ryan's drop tests the bolt is perfectly vertical and it is surprising to show how little that affected the top carabiner.

Back to the original reason for the post, without a dynamic weight load, no point in using dynamic rope. 

He has said he is working on a human representative weight. 

This is just a fast pull test of the scenario "shockload" if you will. 

My biggest disappointment is testing this setup on a single hanger design. I'm sure a smaller, bigger, different hanger would lever a biner over a quicklink much harder. 

Much love for hownot2, my fear lies not in gear, but in the mountains and the people climbing them.