Safety concerns surrounding the Rope Wrench

highclimber30

highclimber30

Location
south carolina
Ok, starting this thread because it interests me because I use this tool. Not only do I use it, I hope that it passes all the tests that it may encounter. Now, those of us who use it know full well that it rides above a prusik of sorts, an eye to eye. Granted, this could be a safety issue (though I don't think it is as dangerous as a footlocking prusik). But, is it more of an issue than is presented to a uni-cender? Never used a uni-cender, I belong to the climbing proletariat (sp?), i.e., don't have the cash. The biggest safety scenario that I can conjure up in my mind, is if something fell on, or if someone grabbed (the climber) the RW and pulled it down onto the hitch below. Couldn't this same thing happen to a uni or even a hitch itself? We all have been trained not to place our hands abouve a footlocking prusik because of this risk, and yet they are still an acceptable tool that is used everyday by someone in the tree care workforce. So, the question is, those of you who know, those of you who are in the position to give the Rope Wrench the thumbs up or down in our industry; which way are you leaning, and why? And, if you lean towards the thumbs down judgement, why would you say no to the Rope Wrench and not the Uni?
 
A simple solution to this concern is to tie slip knot stoppers under the hitch/Uni. Big wall climbers have done this when jugging for years. It's been SOP for rec tree climbing for years also.

A limb 'speedlining' down the rope could happen of course. Has it happened? Not to me but it could.
 
The "speedlining down the rope" scenario has happened to me, but it was while climbing DdRT and the limb in quesion didn't even slow down at the friction knot...it hopped right over and nailed me in the wrist. Not to derail my own post...but if this were to happen, wouldn't the limb have to weigh a significant ammount to run the hitch if all of the climbers weight were in the system?
 
So have you given the RW a shot, Coconut, or have you just made your mind up? Not being a jerk here, just interested to know if you have tried one and hated it. And what descender do you normally use, and how do you normally ascend---RADs, rope walker, tree frog...?
 
I really don't see a safety issue with the rope wrench. Yes something could potentially slide down your rope. If your out on a limb then the RW will be "engaged" It is not going to be forced down the rope when "engaged." I've used the RW and i have been climbing SRT for about 1.5 years and never had this happen and would have no concern with this.

I would find that situation more dangerous with either the Lockjack/sport or Unicender. I find mechancial descenders more of a potential danger. But they are considered except able. If these questions are being raised with the safety of the RW they must also be raised with other devices that could be at risk of the same hypothetical situations.

I would like to see anyone come up with a situation in where the RW or a like device is considered dangerous. I have played out every situation in my head and not one is of any greater concern then the systems we already use.

The Rope Wrench will change tree climbing. I think some think that its a dramatic change. I see its as a different way to accomplish the same feat.
 
anyone ever thought of a doubled rope wrench for footlocking?
grin.gif
 
[ QUOTE ]
doubled line footlocking like you do in competitions. use a rope wrench in place of an double cam ascender. :)

[/ QUOTE ]

Serious?
 
I think the mechanics of a well tied hitch are such that it takes more than the body weight of a climber ot disenghage a locked down hitch. Take for example the ariel rescue in savannah. The dummy was on a footlock prussic. There were a few climbers I watched who tried to break that prussic and were defeated. The thing with a hitch is that it is very very difficult to descendonm without the aid of some kind of descender. Even with the full weight of a 200 pound man pulling on that hitch it is difficult to budge. If you nmanage to break the hitch and get it to slide, you must maintain that pressure or it will stop. This is my experience, others may have found differently.

Could you perform a changeover in the face of a swarm of wasps or a moment of panic in less then a minute? Would "less than a minute" be sufficient to keep you safe? I personally hesitate to ever attach myself to a one way ascender for fear of finding myself stuck. I also change directions maybe 100 times a day. "less than a minute" changeovers would add up very quickly.

I believe that no climbing system should ever be with out a fast route to the ground and to safety.

The dangerous thing about a footlock prussic is that it puts the prussic at full arm extension which is also where you will find the instinctive death grip. Put your hand above the footlock prussic and it is very possible to put that consistant pressure (your body instincitvly makes your hands grip tight when it feels you are about to fall and you need to hold on to something). very scary. This death grip is not possible when the hitch is at the waist.

My beliefe is that the standard footlock ascent into the tree sets the bar very very low as far as safety goes. If your going to allow that, which obviously has some serious inherent dangers involved, then....
 
Well said kevin,
A prusik in my opinion is a far superior form of fall arrest . A "lock down" or "slippage to failure" are the two possible scenarios. A cammed ascender will cut or desheath a rope at relatively low loads and is almost impossible to release under load.
I can not imagine trying a mid-air transfer from a cam setup such as the tree frog to descent system while being swarmed by bees. Rope Wrench requires no transfer; Hence I am already running to the truck for my epipen, while tree frog hopes his ground man would hurry up and lower before anaphylactic comes knockin.
I think the single most important factor to consider with the RW is whether the prusik cordage is compatable with your host rope. Without the WR or added friction a prusik will "Lock Down" or cause a "Slippage to Failure". Every climbing system is prone to this "failure". As long as we understand those components, Climb On and Climb Safe…
 
Not all mechanicals chop rope. There are many that are either designed or function as slip-grabs.

There were pull tests done a number of years ago on a rope dyno to test arbo climbing hitches. The various hitches were pulled at steady or sudden loads and the slip/grab or slip/failure loads were graphed. In almost every combination the prusik slipped to failure. The rest of the hitches had nice slip/grab curves.

I was talking with Chris and Mark [Treemagineers] about a rainy, dreary day of work they did in Switzerland. They noticed a fellow watching them...even though it was a nasty day. When they got done they talked with the man who was watching. Turns out it was Franz Bachmann...ever heard of the Bachman Hitch???...same guy :) He was fascinated by how they used friction hitches. Arbos have a better understanding of working friction hitches than any other working rope discipline. The rest of the rope access methods have gone to mechanicals and the 'tribal knowledge' of rope on rope has resided, and grown, in the trees. That's something to be proud of!
 
http://en.wikipedia.org/wiki/Bachmann_knot. interesting hitch. will have to try it.

I have been thinking a lot about the rope wrench and various certifications. ANZI, CE, ITCC. In part because the rope wrench is only part of the equation, the hitch is the more important life saving part. How can you certify only half of an equation. Is the rope wrench life support at all? Like it would be an excellent belay device for rock climbers if used with a hitch or a back up stop. Better than a gri gri. I wouldn't really want to use it alone. Hitches are difficult to certify because its all in the way you tie them and splice them and what sort of cord your using on what sort of rope and the length of the cord and whether anything is cold, wet, dirty, etc. etc etc. Its hard to put numbers on all that.
 
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