extra lanyard prussik?

You'll have a hard time to find a manufacturer who OK's the choked karabiner configuration.

Karabiners that can do exist, but your average krab is definitvely not designed to hold up to this kind of loading. It can compromise the strength of the connector.
 
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do you condone the improper use of carabiners?

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Of course not, because its not improper.

Before I taught choking techniques, I had concerns, so I spoke to a manufacturer. You have to know what you are doing and why, just like every other aspect of the job.

Any worries, just use a steel karabiner - it'll be lighter and more versatile than a rope guide.

I have found choking to be far more effective and safer than clipping to micro prusiks, or prusik slings made of dyneema.

Like Mark said, Choking CAN weaken the system as much as it doesn't. It certainly comes out on top in my risk assessment.

Maybe you can point me in the direction of the published research on choking krabs, so I can run an appraisal of any tests and variables?
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Absolutely mark I agree.Choking the biner does increase the load trying to pull it apart.If you look at Removal wizards picture of how not to do it,If you can try and imagine the carabina as a block with a lowering rope in( climbing line) you can calculate that the holding or choked side of the rope is holding nearly the same weight as the end holding the climber thus in effect doubling the force on the nose of the biner.....NOT a GOOD PRACTICE.

Didj
 
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Absolutely mark I agree.Choking the biner does increase the load trying to pull it apart.If you look at Removal wizards picture of how not to do it,If you can try and imagine the carabina as a block with a lowering rope in( climbing line) you can calculate that the holding or choked side of the rope is holding nearly the same weight as the end holding the climber thus in effect doubling the force on the nose of the biner.....NOT a GOOD PRACTICE.

Didj

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The chances of the biner failing due to this practice are miniscule, in fact there is about as much chance of the biner failing as there is of the Treemotion not being able to withstand a load of over 100kgs!

If your that worried about that PRACTICE why don't you use a Maillon Rapide instead of the carabiner? Maillons are design for the kind of loading in Remwiz's pic.

There is loads to choose from for all you gear junkies!
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Mr01.gif
 
EN 12275, for example. The glaring omission in the test configs is choking... why? Because it's not a tested configuration, i.e. you are introducing an unknown variable.

I wonder if the manufacturer you spoke to would put their name to that statement in writing? It might raise some interesting liabliltiy issues, I think?
 
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Maillon's not really very attractive on the end of your lanyard.

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you could spray paint it metallic Azare blue
or magenta with a black rippled effect.
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.
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Bit of a pain having to carry a spanner with you to open and close the maillon every time, don't you think?

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How many times are you planning on opening it? I just presumed we were talking about blocking down a spar or similar, in that case you'll only need to open and close it once.......or twice.

In fact I prepose we as an industry stop using carabiners and snaps and switch to Maillons as they are without doubt the safest option.

any thoughts?
 
I have a Kong Aluminum Snap that has signs of deformation from chocking it off into an SRT configuration on smaller material. The paint is all faded is strange lines and is clearly bent. Not good.
 
Hi Todd,
I have also seen nose deformation in tests done in this config.When you start choking lanyards or climbing lines you have to start thinking about slings and rigging and the reduction in strength you have there.As most of you know a sling in choked config reduces the strength of the end to end strength by about 20 to 25% but this it providing the the angle of choke is no less than 75 degrees once you go over this you can weaken the end to end strength by as much as 60% some of this is due to the bend ratio but most of it is to do with increased force from the MA,The sling hasn't suddenly got weaker and the load no heavier.Tockmal ( kiss my Ar#e)in english I guess..
Most Maillons are no stronger than carabinas and the same applies.Both carabinas and Maillons acceptable for industrial climbing are regulated under EN 362/EN 12275
This test does not test choked Configurations.So your remark that maillons are designed for use is completely unfounded.
EN 362 must also conform with EN 365.Included in this Norm is a sentence A manufacturer must in the documentation supplied with the PPE state the :
a) the specific conditions under which the connector may be used;
I haven't seen any Carabina instructions(and I've seen alot)that show a carabina in a choked Config.I wonder why????
Yes there are Biners and maillons that may well take it.but they are not designed or tested for it.
Didj
 
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Tockmal ( kiss my Ar#e)in english I guess..


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didjon

Maillon Rapides are made of steel, even if the Maillon developed a notible bend when used in that situation it is still retaining the majority of its strength.

A Maillon is a very different kind of connector to a Alloy carabiner.
 
i think that i was misunderstood.... choking a biner in this config. is bad as far as loading in the wrong direction, but i agree that you could probly load it with 10 times your weight and not have a problem(i still would not do it even if side loading were the only risk).....


Laz, you mentioned using a steel biner to "overkill" the risk of sideloading by using a stronger material... But you have missed the point. the interface between the locking mechinism and the branch(which is not in the above picture, but with very little moving around it could be) is the larger risk..... I have seen this go very bad... i was rigging some light stuff with an alum. biner, and had it choked around a small limb, when it was weighted(which was wrong and most of the reason that it failed) the gate opened and the biner snapped.... i had the privalege of being in a bucket where i had a birds eye view of what happened....

so i think that you have to be carefull teaching(or doing) that it is ok to choke biners..... why would you need to when there is other methods that are just as quick and better on your gear
 
here is a quote from petzl's directions for use on their ball lock biner

"The carabiner is strongest when closed and loaded on
its major axis; any other position reduces its strength.
The carabiner must be able to move freely and without
interference; any constraint or external pressure on the gate is dangerous."

http://en.petzl.com/ProduitsServices/M34BL_AmDBL_M34502-C.pdf

look at the drawings shown here.... they show a skull and crossbones on the diagram of the biner being side loaded

so Laz, i would say that it is improper to use it that way... let me know if i am missing somthing
 
Yes, Petzl statement is correct. Just as their illustrations of choking karabiners are.

The diagrams warn of cross loading a karabiner. I have yet to see instructions that discuss 'choking' a karabiner along its major axis, there is no pressure on the gate when set up properly. On the contrary, some manufacturers illustrate it well for work based security reasons.

It is obvious to me that there is a major misunderstanding evident in this thread about what is choking in alignment, and what is cross-loading, or actual efficiency of mechanical advantage.

If anything is missing, it is a true understanding of strength vs security.

Rigging with karabiners and using them for personal support are not the same scenario.

And thanks, but I'm well versed and trained in teaching practices and risk assessment. It goes well beyond attending demos, comps and discussion forums.

I disagree with your comments on safer alternatives.
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you have a right to be wrong
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..... but my point is that you can choke a biner in the correct way, but on a climbing system it may not stay in the correct position. it is part of a moving system(me)...

I have seen biners come open with contact on a trunk, and i don't think that you can argue with petzel's instructions "constraint or external pressure on the gate is dangerous"
 
A maillon and clevis might look like a krab; but a maillon and clevis are true dual leg devices. A krab is a single leg device; like an open hook; plus a fancy mousing. Load can be carried in any position along the vlong axis of a dual leg device but only along the solid axis of a single leg device.

Even when carrying load properly along the long axis of a device; we still are leveraging the short axis as it's perpendicular axis of the device as a multiplier against it's own self. Therefore; a wider set maillon, clevis or krab is weaker. But, when carrying across the short axis; we very errantly leverage across the total long axis.

A choke configuration places less inline force/more leveraging on the large axis. A choke configuration against something that isn't flat/ allowing no side force on the krab; then leverages the long axis; even properly set krab. So a free hanging; sharp teepee would be most towards best; as pro-vided by the prussik spaced away from mount.

Let alone a reversed/backward "V" trace of the line placing upwards of 2:1 force on the krab; then multiplied times misalignment forces etc.

The gate of a krab; has pin(s) as the weakest link in that chain/of that side of support. The pin is much smaller than the rest of the body; and it is pulled on it's short axis leveraging across it's long axis. So, even a hairpin gate (that is lighter) is as strong as a solid gate; but a solid risks less loss of strength from rough handling etc. especially in storage etc.

The prussik configuration gives only single leg support to climber; but unless the support/spar is same size as climber the support legs would be at a leveraged angle anyway. Also, the prussik could save climber from being crushed into spar if splitting or ripping where to occur IMLHO.

A choke configuration against mount with krab; risks leveraging across the long axis; unless the mount is flat and places no side pressure on krab. Also risks more chance of miss-alignmeant of the lines, and manipulation of the gate, pressure on the most delicate gate pin etc. all at the same time.
 
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..i don't think that you can argue with petzel's instructions "constraint or external pressure on the gate is dangerous"

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I don't argue with them.

And I don't put external pressure on the gate either.

Its still obvious to me that the mechanics of a correctly choked set up is mis-understood, and the security benefits underestimated.

I'll leave it at that.
 
but that is the problem, you can choke a biner "correctly" and simple movement of the line can cause it to have "external pressure"


there is no way around it......


come back from the dark side!

try the small prussik.....
 
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