working SRT

"Rock Exotica manual is the same as the manual from Thompson Tree Tools except they do not list the ratings. Hmmmm, kind of makes me wonder why they left that part out."

That's where I was going with my inquiry. I thought it better that you find it for yourself. The decisions to let or not let someone use something at a TCC is not an easy one. There is huge liability involved. Those that accept the responibility to judge or tech or time or whatever else must be diligent.
 
From the folks at Rock Exotica:

[ QUOTE ]
Thank you for your inquiry regarding technical specifications for the Unicender. Unfortunately, we have found it difficult to quantify these items because they are so dependent upon rope type (size, construction, age, dryness, etc.). We are currently working with a test lab in Germany to obtain a CE certification. One outcome of this process will be a good set of tensile and slippage data that we can publish. Currently, the best information we have is our User Guide, which is posted on our website at: http://rockexotica.com/products/downloads/rope_grabs.html However, if you have a specific application that you would like to ask about, please feel free to do so.

[/ QUOTE ]

Sounds very much like the same issues with friction hitch and climbing line compatibility.

[ QUOTE ]
I thought it better that you find it for yourself.

[/ QUOTE ] Now you are starting to sound like my Mom.
smirk.gif
 
How do you break test the rope wrench or Unicender in the way it is designed to be used. Merely pulling it end to end does not mean anything and is a waste of time because the device would never experience something like that. A hitch will slide between 1500-3000 lbs somewhere around there. The hitch and the wrench together slip at around 3,000.

If the unicender ever experiences a load greater than what it slips at, than it has been used drastically incorrectly. It should not be used as a linkage point like a carabiner.

How would I set up a test? I would Take a bunch of unicenders and pull on them while they are on a rope (different types of ropes would be best a nice sample). If none of them break before or during sliding down the rope--- the tool passes.

Ascenders : Instead of sliding, they will just cut the rope completely. Whats the point of ratings if the thing your hanging on will just severe your life line at the same weight a hitch or a unicender would just slide. How is that dealt with as a comp judge?

I never tie myself into ascenders and I ONLY use them as climb assist tools. I find them somewhat sketchy and unpredictable and due to operator error have found myself in some awkward situations stuck on ascenders. It is interesting how hard it is to overcome panic when you cant figure out how to get down. Seems likely that will happen in a comp one day with some of the one way systems I see people experimenting with.How is that dealt with as a comp judge? I'm not jealous of your position. Much better to be a climber and complain. :)

I have never climbed with a unicender so I can't speak to whether or not I would allow it.

One thing I found that could be problematic for a competition judge in the Unicender manual was:

"You must always have a backup, never trust a life to a single tool"

a backup? hmmmm



What the manual is trying to say is that in order to use a unicender safely, you need a Rope Wrench.
 
Rope wrench wouldn't be too good as a back-up. Not rated as one. I recently saw a competition where a climber had a rope wrench slip down onto his friction hitch and release it while he was ascending on srt. Speaks to the need to have the correct diameter rope when using these devices.
 
more than rope diameter it sounds like a case of a hitch being tied loose, a loose vt will act much like it does in ddrt and not grab the rope without setting. A distel or Michoacan are more grabby hitches.
 
I've seen the test results from ascenders and ascending knots. Tests can be setup in many ways on a dynomemter.

In one set of hitch tests there were increasing impact loads applied to the hitches. These were singular impacts and the load was maintained.

Another way is to dial-up the load and see when slip/grab takes place.

Another way is to set an impact load and then decrease the load to see how slip/grab loads develop.

Ken James did some testing years ago and found that prusiks were THE worst hitch to use. They slipped to failure, no grab, in even low load tests. The spiraling hitches faired better. this makes sense since the loads on the hitch spirals are applied in a more parallel vector. Prusiks apply a load in a more perpendicular vector.

Take a look at Morgan's rock drop testing of the Unicender. Make what you want with it.
 
Tom,

Do you mind clarifying for this bonehead which hitches fall in your two categories, i.e. "prusiks" and "spiraling hitches".

Does the "prusik category" include english prusik, swabisch, blakes'?

And the "spiraling category" include distel, VT/XT, maybe even tautline??

Thanks.
 
This is the knot that would slip to failure:

http://www.netknots.com/html/prusik_knot.html

Any of the others that had even one crossover that spiraled would slip/grab better.

I sure wish that I had access to that test. It's lost from a PC hard drive crash years ago.

After looking at the graphs from the dynomometer I could see a marked difference in how the various hitches performed. It was enough to convince me to abandon prusiks unless I needed to load them from either direction.
 
Got a Rope Wrench a couple weeks ago, courtesy of Rich H. (for my 2nd place showing at the TX comp, thank you very much). Went out with Crazy Jimmy, Treeweaver and some other guys who showed me how to use it. Very impressive.

It may make an SRT guy out of this old monkey, yet! I have not liked descents on the Unicender that much.
 
Actually, that Rope Wrench came courtesy of Kevin Bingham, Treestuff.com, and ABR as part of their support for the Texas Comp.

To say that we are thrilled that you were on the receiving end of it is a HUGE understatement !! Your climbing was truly inspirational....though I am a bit concerned with my chances of repeating at Geezers : )
 
[ QUOTE ]
Got a Rope Wrench a couple weeks ago, courtesy of Rich H. (for my 2nd place showing at the TX comp, thank you very much). Went out with Crazy Jimmy, Treeweaver and some other guys who showed me how to use it. Very impressive.

It may make an SRT guy out of this old monkey, yet! I have not liked descents on the Unicender that much.

[/ QUOTE ]


Love it!
grin.gif


I just handed mine off to Andy ATrain Young in hopes that he uses it in the Masters against his opponenets at the next AZ comp.
I need it back though Andy, I cant live without it at work.
Come play Saturday....
grin.gif
 
[ QUOTE ]
Actually, that Rope Wrench came courtesy of Kevin Bingham, Treestuff.com, and ABR as part of their support for the Texas Comp.

To say that we are thrilled that you were on the receiving end of it is a HUGE understatement !! Your climbing was truly inspirational....though I am a bit concerned with my chances of repeating at Geezers : )

[/ QUOTE ]

Well in that case, thanks to Kevin as well.
As for any threat in the Geezers, as much as I love all my buds that run that event, I can't bring myself to admit I'm a Geezer quite yet. Maybe when I'm 57 (that's when my dad quit climbing professionally).
 
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