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Mechanical backup to Kong double ascenders

Burnham

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Pete McTree and I have been trading some communications regarding backing up Kong double rope ascenders off and on for a while now. Recently we revisited the subject, prompted by his bringing to my attention a thread at Arbtalk reporting a fall by a climber using these ascenders.

I'll include the link, for those who might be interested...WARNING: the photo included while not specifically graphic, is likely to make any climber squirm.

http://arbtalk.co.uk/forum/showthread.php?t=2360&highlight=kong

This all prompted me to do a bit of experimentation, exploring an idea I have had rattleing around my head. I came up with what I think is a viable method to backup the Kong ascender when footlocking, using a pair of Petzl Microcenders. I used some of that stick-on hook and loop stuff to hold them together back to back, to reduce the clang-bang.

The last pic shows what happened when I opened one cam and loaded the ascender.
Here's the pics. Comments of course welcomed!
 

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Frans

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Any specific reason why you did not use a double Micro-ascender?
 
T

Tom_Scheller

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You might want something between the accessory rope and kong. Biner or link... you know.

TS
 

Burnham

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There are two seperate holes there, the bight is not tight. Even so, you think?
 

treesandsurf

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Burnham, first of all thanks for posting the pics. I've been thinking about this issue ever since I saw that photo from the ISA site of the punctured TM on the fence.

I've been using a slightly difference ascent system. Since I don't have the double kong ascender, I footlock the single rope using the double handed single rope ascender. I've been tying a distel above the ascender and connecting with a carabiner. I like this idea using a microcender. Is there a benefit to using mechanical vs. rope backup?

jp:D
 

treesandsurf

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Yesterday we had set a 1/2" rope at the top of a tree we were removing and I decided to try out the ascender on this rope. Needless to say, it didn't work out too well, kept slipping and the distel wasn't grabbing either as it was held open by the action of moving up the rope.

Maybe the microcender would perform better here?

jp:D
 

Burnham

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Yesterday we had set a 1/2" rope at the top of a tree we were removing and I decided to try out the ascender on this rope. Needless to say, it didn't work out too well, kept slipping and the distel wasn't grabbing either as it was held open by the action of moving up the rope.

Maybe the microcender would perform better here?

jp:D
The ascender was slipping? What rope do you normally use it on?

I've never had trouble with a handled ascender working fine on 1/2 inch rope.

The microcender most certainly would perform well...perhaps a bit more drag than a distel, but it would grip for sure if you needed it to.
 

NickfromWI

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Clever solution. I want to splice it!!!

Okay, that would lock everything together forever...but man, those knots are big!

Does the velcro hold together in a regular climbing scenario?

love
nick
 

treesandsurf

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The ascender was slipping? What rope do you normally use it on?

I've never had trouble with a handled ascender working fine on 1/2 inch rope.

The microcender most certainly would perform well...perhaps a bit more drag than a distel, but it would grip for sure if you needed it to.
I normally use the ascender on blaze or velocity, but we had a 1/2 inch blue streak installed in the tree when I showed up, so tried it out. The ascender did not grip the rope correctly, it would grab sometimes but then slip in small increments down the line or not grab altogether. :O

I'm going to try out the microcender as a backup tomorrow. 8)

jp:D
 

Burnham

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I normally use the ascender on blaze or velocity, but we had a 1/2 inch blue streak installed in the tree when I showed up, so tried it out. The ascender did not grip the rope correctly, it would grab sometimes but then slip in small increments down the line or not grab altogether. :O

I'm going to try out the microcender as a backup tomorrow. 8)

jp:D
What kind of ascender is it you're using?...this is hard to understand.
 

Burnham

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Clever solution. I want to splice it!!!

Okay, that would lock everything together forever...but man, those knots are big!

Does the velcro hold together in a regular climbing scenario?

love
nick
Nick, you can't splice EVERYTHING on the planet :lol:. The knots are not big, they are just the right size :). "To a guy with a hammer, everything looks like a nail" :P.

Yes, in the couple of test climbs so far they stayed secured back to back...when I tested the backup function they seperated as the tether between them tightens asymetrically.
 
W

Wagnaw

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Burnham, Have you tested that back up much? Try to footlock on one side of the line to see if it stays secure. The fact that it's one rope running between the two concerns me a little but only because I haven't seen it done like that before. Clever idea!
 

Burnham

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Wag, if you pull on one leg of the rope, either by footlocking it or intentionally pulling it ala body thrusting, the doubled rope loop above the ascender just gets smaller, exactly like DbRT. The backup has no effect in this, that's just the way the double rope ascenders deal with that scenario.
 
T

top hopper

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I like it!

But I DONT like the black rope just fed through those ascender holes. I could see those edges shredding the rope if loaded hard. Id add some sort of link to it.
 

Burnham

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You might want something between the accessory rope and kong. Biner or link... you know.

TS

I like it!

But I DONT like the black rope just fed through those ascender holes. I could see those edges shredding the rope if loaded hard. Id add some sort of link to it.
That is the only aspect of this arrangement that I looked at with any scepticism. It would be an easy mod...but I'm really pretty comfortable with it the way it is. The distance of drop possible if a cam fails or the rope escapes the ascender is only 8 inches or so...as we all know well, one MUST make sure one never gets in a position to take a significant drop on a toothed ascender, cam failure aside. The distance between the two holes keeps the radius of turn the rope tether takes through there from being tight like it would be in a single hole in similar stock, and less tight than it would be around a screwlink. The edges of the holes are rounded and finished smoothly.

So I don't feel it's necessary to go with a link there, but I do see y'alls point and I'd not try to dissuade anyone from using a link there. The main reason I don't want one there really is so it's not clink-clink-clinking as I climb :).

This pic shows that part a little better.
 

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pete mctree

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Small piece of flexible hose with rounded ends (could even be shaped a little) would solve the issue of running the cord over such a sharp metal radius
 

NickfromWI

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Small piece of flexible hose with rounded ends (could even be shaped a little) would solve the issue of running the cord over such a sharp metal radius
I was thinking you could wrap a piece of padded leather and sew it in place to increase the bend radius.

But I'm with Burnham on this one. I don't think the type of fall this setup could ever see would ever do enough damage to the rope to prevent it from serving its purpose.

love
nick
 
T

top hopper

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You could use a small piece of an old webbing sling over the rope, most of them are hollow. That would protect it well.
Im not so concerned about the bend radius, just more so the sharp(ish) edge of the hole and its potential cut.

I agree though, probably good enough though. Im always looking to improve improvements.

I like the velcro to hold them together, and I especially like people using a PROPER back up on doubles line.
 

Old Monkey

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Cool stuff Burnham. I think you should work as a teacher and consultant after you retire from the Forest Service. I am certain I could get some folks together here in Boise for a training session.
 
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Frans

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I would promote you, Burny.

In fact the CAA is ALWAYS seeking folks to put on climbing skills workshops or even to add to one.
 

treesandsurf

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What kind of ascender is it you're using?...this is hard to understand.
This is a CMI, double handed ascender. The catalog says it works on 1/2" lines, didn't grab reliably on the ascent however.

I tried this method tioday on a 80' ascent and noticed that the action of forcing the ascender into the microcender dings up the top portion of the ascender. Have you noticed this too Burnham?

Other than that, I felt very confident using the mechanical backup over the VT or distel above the ascender.

jp:D
 

pete mctree

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A bit of food for thought:

The problem occours when a single cam opens, and the system goes into freefall as a single doubled rope is used. So if both lines were static, then BOTH cams would have to fail, therefore would any back-up be required as they would be acting independantly?

Here is an example, shown to me by Chris (puwer) on arb-talk.

1st set up a single line srt style (in this instance it is configured so that a ground rescue can be fascilitated- always a bonus)
2nd with the use of a rated ring, a 2nd rope is attached to the primary line at a point when hauled up it will be just either side of the fork selected.
3rd haul up voila! 2 isolated lines configured for drt ascent.

It helps if the 2nd rope is the same or similar to foot lock on.
 

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Burnham

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I like it, Pete. I like it alot. I'd probably go for a different knot, like an anchor or buntline hitch to attach the second line, just 'cause the figure of eight knot locks down so tight when loaded, but that's a nothing quibble.

I do think I'd miss the ability to body thrust the doubled line as my system allows...there are points in an ascent via footlock, in conifers especially, that getting by limb whorls is greatly facilitated by that capability.

As for needing a backup...I say it would not, following the normal SRT system protocol of needing two seperate life support capable attachment points to the lifeline mounted at or above center of gravity...only caveat is there is only one tether from the double ascender to your harness, so some might call that a short-coming.
 
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