Have you used a Kong "Indy" descender?

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Have you used a Kong "Indy" descender?

Postby jmo » Dec 1, 2005 9:13 pm

This descender looks pretty sweet! It looks a lot like the Petzl stop, just with braking in a push/release situation. Which is a nice feature after hearing horror stories about people grabbing the Petzl stop in a panic, and sailing the down the rope.

Have you ever used one or have you seen one in action?
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Postby Lava » Dec 2, 2005 6:53 pm

I thought it looked pretty sweet too, so I bought one, mostly out of plain gearlust. I tried it on stiff 11mm PMI and it wouldn't move an inch (shocker). It was even slower than my Petzl Stop on that stuff. All of that was okay until I realized it is apparently unsafe for 9mm rope, as per the diagram etched on it. Come on now. If it's not going to move at all on 11mm maxi-wear, you'd think it would (or should) work on 9mm. It's as if, in an attempt to design it to be compatible with either North American or European SRT, they could only manage a range in between the two, leaving out the extremes completely. Ah well. So you have to use 10mm or go 11mm ez-bend. Its workmanship appears to be top-notch, but I don't really like it. However, that may change as my mostly 11mm ropes die off and I slowly replace them with 10mm ez-bend.
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Postby jmo » Dec 4, 2005 4:13 am

Bruce - Thanks for your input on the Kong Indy. I guess I should check out SRT Descenders. I have heard only very good things about them, but they are very pricey.
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Postby NZcaver » Dec 4, 2005 3:42 pm

jmo wrote:Bruce - Thanks for your input on the Kong Indy. I guess I should check out SRT Descenders. I have heard only very good things about them, but they are very pricey.


Lava's analysis of the Kong Indy makes interesting reading. Thanks! Years ago I used to use its single-brake predecessor - the Kong Speleo. I recall it seemed to work OK on 10-11mm, but I eventually upgraded to the Petzl Stop because it's much easier to get on and off rope. It seems many double-brake devices have a narrower range on rope tolerance - I guess that's the trade-off. :?

JMO - the SRTE descenders you mentioned are indeed comparatively expensive, especially the double-brake versions. And they are heavier and a little bulkier than most other bobbins, but are still smaller and lighter than many racks! Considering the weight and price, they are probably more suited to industrial applications. They do work nice, though - at least my single-brake one does. By design, adjusting your grip on it's handle gives you a second means of friction control in addition to your 'rope' hand - a technique Petzl does not recommend when using their Stop.

Have you seen the Anthron Double Stop Descender? I know a few people who use them, and they seem to be happy. Check out this review - http://www.cavediggers.com/Anthron.pdf They retail for about $100, but if you shop around you can probably knock some dollars off. Try - http://www.rescuedirect.com/Merchant2/m ... re_Code=RD

Pictures of the Anthron and the Indy... (and by the way, the Anthron can be used just as easily right-handed)

Image

Image

Good luck! :grin:
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Postby Ralph E. Powers » Dec 5, 2005 12:06 am

A friend of mine just bought one and wanted to try it out. I looked it over and saw how nicely it was put together. Still, it's going to take her some getting used to trying to find that happy medium between stop and go.

JMO, just wondering if there's any documentation of people "grabbing the stop in panic and go sailing down the rope..." just wondering... like to read that for myself.
IMO panicky prone people shouldn't belong on rope. But that's just me.
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Postby NZcaver » Dec 5, 2005 4:24 pm

Ralph E. Powers wrote:JMO, just wondering if there's any documentation of people "grabbing the stop in panic and go sailing down the rope..." just wondering... like to read that for myself. IMO panicky prone people shouldn't belong on rope. But that's just me.


Ralph - it's not really 'documentation', but if you look way down the DB the "spinoff post about the stop" talks about grab panic. :shock:

Chaz posted this:
A few years ago, my cousin was in town and wanted to go caving. After a training session we proceeded to drop several pits in the 40 foot range. He was doing great! We then progressed to something a little deeper, a 70 ft pit with a hole in the wall that leads to another 30 ft of depth (nicely decorated) Here we go... He got down in position to swing over and grab the hole, but he missed and in a panic grabbed the stop in front of him! I heard an OH and a THUD! I called down to him and he was thankfully alright. He said "I accidentally grabbed the red handle and dropped 15 ft real quick". We passed on the second drop but we did learn what can happen with a stop. Even after drilling him about it! Chaz


And this was part of my post in reply:
Actually, I saw the same thing happen years ago to a novice using a Kong Speleo (similar to a Stop). He did a knot pass (for practice) while rappelling down a cliff, then grabbed the handle to continue his rappel without first grabbing the rope below with his other hand. He sped down the last 10m/30ft of a rope and hit the ground, breaking his wrist while still trying to grab the rope below his descender. He was lucky.



I understand your concerns about putting panicky people on rope. However, there's a first time for everyone - and there's usually some nervousness, if not panic, involved. After that, some people remain naturally more jittery than others on rope. I've coached many people who fall into this category. Personally, at the start of a nice drop, I get a little rush almost every time. I turn those butterflies into motivation to check my gear 'one more time', and off I go. Interestingly, if I'm tandem instructing and focused on the student, I don't get the same rush. Just when I'm on my own. :wink:

Having said all that, I've never felt an irrational reflex to grab a stop handle while on rope. Hence I prefer using a single-brake descender in keeping with my basic KISS principle. I noticed the review of the Anthron totes it as an ideal descender for first-timers, because of the double brake. They do have a valid point, so long as the beginner is taught that their rope hand is their primary method of control - the same as with virtually any other descender.

And for novices and those who are not so confident, there really should be a bottom belay provided. Actually, anybody should be comfortable asking for one if they feel they need it. :grin:
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Postby hank moon » Dec 5, 2005 4:55 pm

And for novices and those who are not so confident, there really should be a bottom belay provided. Actually, anybody should be comfortable asking for one if they feel they need it.


Further to this: people lacking sufficient confidence should not learn how to rappel in-cave. Rappel outside (with a TOP belay) until you feel good enough to go to a less reliable protection method (e.g. bottom belay). Note that a bottom belay can produce undesirable effects with certain devices. For example the Petzl STOP can invert completely, which results in a dramatic reduction in friction.

A friend recently told me of an incident where a STOP was used on a very long drop. The rope weight was such that the device tended to self-invert and the user had great difficulty maintaining the STOP in the correct position. He saved himself from zipping by quick installation of a Jumar.

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Postby ian mckenzie » Dec 5, 2005 5:53 pm

hank_moon wrote:For example the Petzl STOP can invert completely, which results in a dramatic reduction in friction.

A friend recently told me of an incident where a STOP was used on a very long drop. The rope weight was such that the device tended to self-invert and the user had great difficulty maintaining the STOP in the correct position. He saved himself from zipping by quick installation of a Jumar.


The 'inversion' can occur when the rappeler takes part of his weight off the rope (e.g. places a foot on a ledge); I think it would have to be a pretty heavy rope beneath you to invert the Stop under full body weight. Your friend could have 'saved' himself simply be putting his full weight onto the Stop.

Ditto for bottom-belays; I should think an inversion could only occur in combination with the rappeler resting on a ledge (which could happen, of course, but once they slipped off, the normal situation should return).

This is a first-class-lever math problem; any takers?
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Postby NZcaver » Dec 5, 2005 6:00 pm

hank_moon wrote:Further to this: people lacking sufficient confidence should not learn how to rappel in-cave. Rappel outside (with a TOP belay) until you feel good enough to go to a less reliable protection method (e.g. bottom belay). Note that a bottom belay can produce undesirable effects with certain devices. For example the Petzl STOP can invert completely, which results in a dramatic reduction in friction.


Oh yeah, that too. 8) Get comfortable rappelling above ground before trying it below. Thanks, Hank! :wink:

Not to open another can of worms, but TOP belays can sometimes cause problems too. If you're on a free hang drop and you start spinning, the ropes will twist around each other and lock you up real good! Especially if you're using an evil figure-8 descender. :twisted: The 100% redundancy factor of using 2 ropes doesn't do you much good when you're stuck on rope and need to be rescued. :roll:

When it comes to vertical caving, any SRT belay can either be a self-belay, or a bottom belay. Using a top belay means a second rope - and then it's not Single Rope Technique any more! Plus it's often tough enough to manage one rope at an in-cave drop, let alone two. But using a top belay for running groups of novices down regular cliff faces, rappel tower faces, or buildings - sure.

Great info on the inverted Petzl Stop death trap - I hadn't heard that before. Any idea of roughly how much lower rope weight it would take before that starts happening? I'd assume the caver's weight would need to be factored in too, but it would be good to know a ballpark figure for, say, a 180 lb caver. Another test for Petzl to run, perhaps? :grin:

PS - After reading what Ian just posted, I have to agree with him. I imagine it would be near impossible to have the Stop invert unless you have a LOT of bottom weight AND you partially unweight your descender. I would think most people can't physically lift the amount of rope it would take to invert their Stop descender while their full body weight is on it - and therefore they couldn't rappel anyway! Still, worth investigating. 8)
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Postby hank moon » Dec 5, 2005 7:24 pm

I think it would have to be a pretty heavy rope beneath you to invert the Stop under full body weight.


It was very heavy: 350+ m, 11 mm, nylon, wet (waterfall drop). His full weight was on the STOP.
Last edited by hank moon on Dec 5, 2005 7:34 pm, edited 2 times in total.

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Postby hank moon » Dec 5, 2005 7:28 pm

Not to open another can of worms, but TOP belays can sometimes cause problems too. If you're on a free hang drop and you start spinning, the ropes will twist around each other and lock you up real good! Especially if you're using an evil figure-8 descender. The 100% redundancy factor of using 2 ropes doesn't do you much good when you're stuck on rope and need to be rescued.


Twist prob is generally solved by offsetting the belay. Best to train on a slab or vertical wall first anyway where twist is non-issue. Finally, a contingency anchor on the rap line will allow the rappeller to be lowered to ground at any time.

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Postby David_Campen » Dec 5, 2005 9:36 pm

The 'inversion' can occur when the rappeler takes part of his weight off the rope (e.g. places a foot on a ledge); I think it would have to be a pretty heavy rope beneath you to invert the Stop under full body weight. Your friend could have 'saved' himself simply be putting his full weight onto the Stop.

We had a long discussion about this in a previous incarnation of this Discussion Forum. I had reported the condition with the Stop tending to tip over due to weight of the rope below. In my case it was about a 300 ft drop and the Stop would only partially tip over when I transfered my weight to the walls. I found this behavior a bit disconcerting and decided that I would no longer use a Stop on drops over about 150 ft.
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Postby jmo » Dec 6, 2005 2:52 pm

The Anthron Double Stop Descender looks pretty sweet as well. I was talking with an employee of a local climbing store and he said there are some plastic pieces on the Anthron that tends to wear out quickly and is not replaceable like the bobbins on the Petzl Stop and the Kong Indy. I'm not sure if there is any truth to this, as he kept on trying to sell me the Petzl Stop.

Also, thanks for the links to all the info. I appreciate it.



NZcaver wrote:
jmo wrote:Bruce - Thanks for your input on the Kong Indy. I guess I should check out SRT Descenders. I have heard only very good things about them, but they are very pricey.


Lava's analysis of the Kong Indy makes interesting reading. Thanks! Years ago I used to use its single-brake predecessor - the Kong Speleo. I recall it seemed to work OK on 10-11mm, but I eventually upgraded to the Petzl Stop because it's much easier to get on and off rope. It seems many double-brake devices have a narrower range on rope tolerance - I guess that's the trade-off. :?

JMO - the SRTE descenders you mentioned are indeed comparatively expensive, especially the double-brake versions. And they are heavier and a little bulkier than most other bobbins, but are still smaller and lighter than many racks! Considering the weight and price, they are probably more suited to industrial applications. They do work nice, though - at least my single-brake one does. By design, adjusting your grip on it's handle gives you a second means of friction control in addition to your 'rope' hand - a technique Petzl does not recommend when using their Stop.

Have you seen the Anthron Double Stop Descender? I know a few people who use them, and they seem to be happy. Check out this review - http://www.cavediggers.com/Anthron.pdf They retail for about $100, but if you shop around you can probably knock some dollars off. Try - http://www.rescuedirect.com/Merchant2/m ... re_Code=RD

Pictures of the Anthron and the Indy... (and by the way, the Anthron can be used just as easily right-handed)

Image

Image

Good luck! :grin:
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Postby jmo » Dec 6, 2005 3:00 pm

Ralph E. Powers wrote:JMO, just wondering if there's any documentation of people "grabbing the stop in panic and go sailing down the rope..." just wondering... like to read that for myself.
IMO panicky prone people shouldn't belong on rope. But that's just me.


Ralph - I haven't seen actual documentation on this either, I have just spent a lot of time on the forums at rockclimbing.com and I have read about many horror stories there.
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Postby jmo » Dec 6, 2005 3:12 pm

The Petzl Stop seems great, but when you taking someone along who like you said does not have a lot of confidence rappelling, but still has some experience rappelling it just seems like a very good idea to have a double braking descender just in case they do grab a hold of the descender in a panic.

Also, has anyone tried out a Petzl shunt on a single 10mm line? I'm interested to hear how these work on ropes that can have elements on them like in caving situations. Friction knots such as the Prusik has always worked well, but sometimes they can be hard to unload once they have been set.
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