carabiner for Kong ascenders

[Mahk_Adams]

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Mark have you tried a DMM Boa

Didj

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Just tried it and it doesn't work.

TRhanks for the suggestion though.

 

[Mahk_Adams]

Tom had suggested some type of screwlink, but I couldn't find one of those that worked either.

Bruce Smith showed me a shackle he had been using on the ascenders. He then clipped a biner to the shackle and had spliced the middle of a piece of cord to the biner. The cord had an eye on each end and he made side-by-side French prusiks and clipped the eye ends back to the biner. The attachment shows a modification of his setup.

The shackle is the same shackle that is used to hold the leg portion of the ButterFly II. It is cheaper ($6 from Sherrill)than a bow shackle from a marine store and the pin is completely embedded in the bow i.e. one end of the pin has a recessed allen head slot to tighten it and the other end of the pin screws directly into threads on the bow. A 1/2 inch line can be pushed past the shackle with a minimal amount of effort and an 11 mm line (shown in the following attachments) goes slides in very easily.

The cord is 3/8ths Tenex spliced directly to the shackle with a locking Brummel.

 

[Mahk_Adams]

Splicing the line directly to the shackle meant that the carabiner could be eliminated. But, it also meant that the hitch that is used to attach the cord to each leg of the climbing line has to be an open hitch. This is basically a 4 over 1 tautline, tied from top to bottom.

This is how it would look as the ascenders push the hitches up the legs of the climbing line.

 

[Mahk_Adams]

Different view. The hitch needs to be loose enough so that it creates little additional friction as the ascenders are pushed up the line...

 

[Mahk_Adams]

yet there needs to be enough friction so that either hitch will grab if one of the cams fails.

 

[Mahk_Adams]

Here one of the cams has been opened to simulate failure, jamming or inadvertent opening. As the climbing line moves the hitch tightens and prevents the climber from falling to the ground.

 

[charlieb]

Mahk,
What about a clevis shackle?
Also, whatever shackle you use, couldn't you also use an advanced closed hitch, like knut, VT, XT, etc. and have each end of the hitch line knotted to the top of the shackle just like you would do if it were a carabiner?
These hitches would give much less resistance I believe than a Tautline.

 

[Mahk_Adams]

Different view. The cam on the blue side of the ascender is open and the hitch on that side has grabbed the line.

 

[Mahk_Adams]

Here is one other use for this setup.

Some people use a hitch backup when ascending a single line. If they climb off of the ascender they first pull back the cam, load the hitch and then let go of the cam so that it sits back on the rope. This puts the load of their climbing on the hitch rather than on the cam. The system is further backed up with a marling spike below the ascender.

People climb off of the Kongs as well, especially in the aerial rescue event at TCC's. The climber is required to put a marling spike below the ascenders, but I have never seen anyone take the load off of the cams. In this photo the cams were pulled back, the load was placed on the hitches, then the cams were let go so they sat back on the legs of the rope. Most of the force that the climber will generate will now be on the hitches rather than the toothed cams.

 

[Mahk_Adams]

[ QUOTE ]
What about a clevis shackle?


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That is what Bruce was using, but the flat part of the pin (what you would hold to un/screw the pin) made the pin a little longer than the recessed pin of the bow shackle and made a 1/2 inch rope a very tight fit.

[ QUOTE ]
Also, whatever shackle you use, couldn't you also use an advanced closed hitch, like knut, VT, XT, etc. and have each end of the hitch line knotted to the top of the shackle just like you would do if it were a carabiner?


[/ QUOTE ]

Bruce used a Valdotain. He had an eye spliced in each end of the hitch line and just slipped the eye over the biner after each hitch was tied.

I wanted to eliminate the biner. The pin of the shackle is secured with Lock Tite. If I used a closed hitch I would either have to tie the end to the shackle after tying the climbing hitch; or I would have to use the shackle without Lock Tite. I would tie the hitch, thread the knotted (or spliced) eye on the shackle and then insert the pin. The process would have to be reversed to take the ascenders off. Since this would be done in the tree, there was the possibility of dropping the pin and/or shackle. Without the biner, it seemed easier to use an open knot.

[ QUOTE ]
These hitches would give much less resistance I believe than a Tautline.

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When ascending the tautline does not give much, if any, more resistance than some of the other hitches. It is essentially five wraps around the climbing line, which is the same, or less, than other hitches. The tautline binds when descending, which (right now) is not the intent for this setup.

But, you're right, the hitch is still something that needs a lot of field analysis. Because the two hitches are right next to each other, I have wondered if a hitch that is easy to release could catch on the hitch on the other side of the line and cause a freefall.

I have also thought of putting a Dualcender above the Kongs as a backup, but have only tried it in my garage.

 

[TreeCo]

Hey Makh,

Attached is a hitch I came up with a few months ago.

It has some interesting properties I think. Plus it's damn pretty.

 

[TreeCo]

And the other side.

 

[Mahk_Adams]

I remember seeing that before. Did you post that on AS? It does look cool.

Have you tried it yet? How does it work?

 

[TreeCo]

Never climbed with it but does lock when either rope is pulled either direction. I did post that on AS. We were brainstorming a knot for your very application I believe.

When I SRT I use the CMI prefab frog system on a single line. I don't have a set of the double ascenders.

 

[Sawdust]

If you still want to use the Kong dbl.(why, I'm not sure but,)just use a klem. above and throw in a hitch pin to lock the rope. There are quite a few out there that will serve the purpose. It will even have a small chain so you can attach it to your konger and not lose it. Give it a shot and let us know.

P.S. SRT

 

[Mahk_Adams]

[ QUOTE ]
...just use a klem. above...

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Do you mean form a klemheist around both legs of the climbing line above the ascender? That won't help if one of the cams fails. The climber will still fall.

[ QUOTE ]
...throw in a hitch pin to lock the rope.

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Do you mean that the hitch pin is to keep the cams from opening and prevent the rope from coming out of the ascenders? That's not what this setup is for--but, if that did occur, this setup would prevent the climber from falling.

 

[didjon]

Hi Mark
I'm Thinking of the wrong Bina.The One I'm thinking of must be a Mammut.Its the same shape as the BOa but is a bit bigger and the profile a bit thinner.
It doesn't go where you have put the shakcle but through the four holes that are in line on the top of the cam the ones for holding the rope in.Let me see if I can find one,I had this discussion with a friend of mine a couple of years and Said to him I didn't think there was a bina that would fit through these holes he proceeded to take a bina from his belt and fit it through I spoke to him today and he seems to remember it was a Mammut,I will find out for sure and let you know...But the system you have come up with looks good.A thought that I had about backups on cams is if you set a butterfly in your access rope you only really need a prusik hitch on the end that pulls down and bites the butterfly up

Later Didj

 

[Tom Dunlap]

This might have been mentioned before, if so, sorry, if not, here it goes...

It's very common in rock climbing to "tie off short" make a stopper knot below ascenders or tie clove hitches to protection to keep the rope from running in case of a fall. this shortens the amount of rope in the system.

For years I've had rec climbers tie slip knots in the down rope, below their friction hitch. If they slipped, the fh would stop at the slip knot. I started to do the same when I've been working on a new fh setup for SRT. Depending on my comfort level with falling the backup may be no more than a couple of feet or several feet.

Why not encourage arbos to use more backups? It only takes seconds and could save a life.

 

[Sawdust]

The klem above would be attached seperately, like a short footlock attachment. If anything happens to the kong you would hang on the seperate line. A true backup. Keep in my too the kong is not a fall arrest device. Sure it would hold you. Just a thought.

The hitch pin would go through all 4 holes to align the rope better so you don't angle it out. I've seen it on older jumars. Someone already mention they put acces. biner through the smaller hole to limit cam travel.

Seems like it's getting to be too much. SRT
As soon as I get my camera working again I'll post some pics.

Later

 

[Mahk_Adams]

[ QUOTE ]
The klem above would be attached seperately, like a short footlock attachment. If anything happens to the kong you would hang on the seperate line. A true backup

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If the klem is formed around both legs of the line and one of the cams fails, the klem will not hold. One cam will still be engaged on the rope. This will pull that end down and the klem will not prevent the other end from running up. In this situation the klemheist (or a Prusik) is <u>not</u> a true backup.

[ QUOTE ]
Keep in my too the kong is not a fall arrest device.

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Right, its just an ascender.

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The hitch pin would go through all 4 holes to align the rope better

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I'm not concerned with trying to align the ropes better. I haven't had any trouble with them feeding into the ascender.

[ QUOTE ]
Someone already mention they put acces. biner through the smaller hole to limit cam travel.


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Yes, both Wolter and I said that we do that.

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Seems like it's getting to be too much. SRT
As soon as I get my camera working again I'll post some pics.

[/ QUOTE ]

I understand what you're saying and the points you describe. But, the klemheist is not a backup for this setup, and I'm not trying to align the legs of the rope any better. Nor am I making an argument for or against ascending DdRT or SRT.

Many people use the Kongs for ascending a doubled rope. I'm simply suggesting a backup for that system in case either one or both of the cams fails or comes off of the rope.

The Kongs are also used as a floating false crotch. This backup for the Kongs would hold most or all of the force generated by the climber's movement and would greatly reduce the impact of the cams on the access line.