STOP USE on the ZigZag
- Thread starter TreeStuff
- Start date
tuttle
New member
- Location
- Somewhere in the 21st century
Where has this been stated?
Its my thoughts exactly to tell people to stop using them, plus it would be great to find out more about the manufacture process.
Its the one rivet thats the greatest concern.
Its my thoughts exactly to tell people to stop using them, plus it would be great to find out more about the manufacture process.
Its the one rivet thats the greatest concern.
tuttle
New member
- Location
- Somewhere in the 21st century
- Location
- Northern NJ
If you don't wanna download anything, here's a post I threw up on The Dripline.
http://dripline.net/2013/04/19/safety-alert-stop-use-petzl-zigzag-mechanical-prusik/
http://dripline.net/2013/04/19/safety-alert-stop-use-petzl-zigzag-mechanical-prusik/
treebing
Been here much more than a while
- Location
- Detroit, Mi.
I wonder is this dangerous configuration possible with a hitchclimber pulley? Or maybe the stein skywalker? I don't see why it would not be
It may be that the holes in the hitch climber are just a bit larger than the hole in the top attach point for the ZZ, just enough to minimize cross loading. Also the hole appears slightly triangular in the ZZ, this makes me think it may tend to cross load easier. Perhaps someone who has both could compare the two?
moss
Been here much more than a while
- Location
- Carlisle, Massachusetts, U.S.
[ QUOTE ]
I wonder is this dangerous configuration possible with a hitchclimber pulley? Or maybe the stein skywalker? I don't see why it would not be
[/ QUOTE ]
Just playing around with a DMM oval and a Hitchclimber pulley for a couple minutes I've found a couple positions that lock into a leveraged side load.
I think... that experienced tree climbers are constantly inspecting and adjusting these connections as they climb, almost as an unconscious activity. Folks may take it for granted how much they actually monitor their system components to make sure everything is behaving properly.
Think of this scenario... you descend down and land on a limb, lanyard in and do some trimming. Now you're done, you take your lanyard off the tree and prepare to reload your main rope and move down to the next task. I don't believe any of you would jump off the limb without tightening up the slack and taking a quick look at your hitch/device and carabiner connections before reloading your main system.
In order to break the ZZ connection point the climber would have to slack his main system (probably lanyard in), and then reload the main system without looking at the carabiner connecting the static leg of his DRT system to the ZZ.
Makes me want to know more about the climber who broke their ZZ and fell. They were climbing indoors on structure right? Are they actually a tree climber or are they an industrial climber? How familiar were they with DRT tree climbing systems?
-AJ
I wonder is this dangerous configuration possible with a hitchclimber pulley? Or maybe the stein skywalker? I don't see why it would not be
[/ QUOTE ]
Just playing around with a DMM oval and a Hitchclimber pulley for a couple minutes I've found a couple positions that lock into a leveraged side load.
I think... that experienced tree climbers are constantly inspecting and adjusting these connections as they climb, almost as an unconscious activity. Folks may take it for granted how much they actually monitor their system components to make sure everything is behaving properly.
Think of this scenario... you descend down and land on a limb, lanyard in and do some trimming. Now you're done, you take your lanyard off the tree and prepare to reload your main rope and move down to the next task. I don't believe any of you would jump off the limb without tightening up the slack and taking a quick look at your hitch/device and carabiner connections before reloading your main system.
In order to break the ZZ connection point the climber would have to slack his main system (probably lanyard in), and then reload the main system without looking at the carabiner connecting the static leg of his DRT system to the ZZ.
Makes me want to know more about the climber who broke their ZZ and fell. They were climbing indoors on structure right? Are they actually a tree climber or are they an industrial climber? How familiar were they with DRT tree climbing systems?
-AJ
- Location
- Retired in Minneapolis
Take a look at the bottom hole of a stamped metal handled ascender. Why haven't we heard about someone tearing that single layer of aluminum from cross loading a biner there?
Handled ascenders have been around for decades longer than the ZZ. It seems like someone would have had this dangerous configuration happen with a handled ascender by now.
Handled ascenders have been around for decades longer than the ZZ. It seems like someone would have had this dangerous configuration happen with a handled ascender by now.
tuttle
New member
- Location
- Somewhere in the 21st century
I believe it's the length of rope acting as 40ft+ lever on the cross loaded, messed about with a grillon, hand ascender and hitchimber to think of the same, can't see it happening.
rockettree
Participating member
- Location
- Boulder, CO!
[ QUOTE ]
Take a look at the bottom hole of a stamped metal handled ascender. Why haven't we heard about someone tearing that single layer of aluminum from cross loading a biner there?
[/ QUOTE ]
Because the teeth on the ascender destroy the rope before the metal components fail?
Take a look at the bottom hole of a stamped metal handled ascender. Why haven't we heard about someone tearing that single layer of aluminum from cross loading a biner there?
[/ QUOTE ]
Because the teeth on the ascender destroy the rope before the metal components fail?
- Location
- Retired in Minneapolis
[ QUOTE ]
[ QUOTE ]
Take a look at the bottom hole of a stamped metal handled ascender. Why haven't we heard about someone tearing that single layer of aluminum from cross loading a biner there?
[/ QUOTE ]
Because the teeth on the ascender destroy the rope before the metal components fail?
[/ QUOTE ]
Msybe...
That's what we're always told by the manufacturers and testers. What about out in the real world? What happens if the ascender slips but hits a stopper? All sorts of possibilities.
[ QUOTE ]
Take a look at the bottom hole of a stamped metal handled ascender. Why haven't we heard about someone tearing that single layer of aluminum from cross loading a biner there?
[/ QUOTE ]
Because the teeth on the ascender destroy the rope before the metal components fail?
[/ QUOTE ]
Msybe...
That's what we're always told by the manufacturers and testers. What about out in the real world? What happens if the ascender slips but hits a stopper? All sorts of possibilities.
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
The rope length doesn't act as a lever.
We've played with a lot of configs and it seems the DMM oval def bites and locks in place on the zz, petzl ok is better and the ISC oval won't side load as it's too fat. The HC will side load too but Te round holes make Te carabiner a lot more likely to self align in the right position.
- Location
- Victoria, BC
I don't think comparisons to these other devices are fair. Apples to oranges. The ZZ is unique in that it essentially has three points of connection: the links on the rope above, the swivel to the climber below, and the terminal connection. The first two pull linearly in opposite directions essentially holding it in its orientation. Any levering action by the terminal carabiner can actually be exerted on the frame of the device. In the example of the handled ascender rotational camming would cause the bottom of the ascender to come off line to balance the vectors. Only slightly but it would make a difference. I hate speculating on things like this but I think it's worth mentioning how this kind of carabiner misalignment affects this device differently than all others. Only a lockjack or unicender in drt could be analagous.
moss
Been here much more than a while
- Location
- Carlisle, Massachusetts, U.S.
Murph, thanks for articulating that so clearly. Word.
-AJ
-AJ
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