Bogley

[ratagonia]

Bo_Beck wrote:
Yes Rich, I did look at the test figures that Sonny posted. The one thing that isn't addressed, but that Tom mentioned, is that the tests were done using a dyno, but failed to suggest at which point the forces were highest (only one of the variables). I did notice that Sonny mentioned that the angle was 30 deg. or so though. It is true that the tighter the line, the greater the forces that can be expected. The forces are generally going to be highest somewhat around midspan, depending on the angle of the rope. I just worry that with some of the rickity anchors that are found in some of the canyons, that someone may turn a guiding line into a Highline by accident and be involved in catostrophic failure. I tend to believe that if the anchors are questionable, then build them up, or use a skate block and hope that it will keep you dry!

Except that Hubert's calculations are a model of the system, and Sonny's measurements are for one particular system, so take them as an indication, not a law.

Highest forces are found at the very bottom of the guideline, when the rappeller's weight is 100% on the guideline, and the guideline is as flat as possible - in other words, just before the rappeller touches down or drops into the pool.

Big guided rappel in Water Canyon, using 160 feet of Canyon Pro, force generated was only 3X my corpus weight of 200 lbs. approx 45 degree rigging angle.

While Rich may find it silly to guide rappels in Class B canyons "to avoid a little puddle", I find "IT DEPENDS". The only way to maintain skills and understand rope skills is to practice them, so then they are needed for rescue or to avoid hypothermia (or to avoid potholes, or to have MORE FUN), or to allow Tanya from getting wet (obviously, a HIGH PRIORITY if I've ever seen one), then perhaps they are not silly.

Again, I think the key point is, don't make the guided rappel any tighter than it needs to be; and use good anchors.

Tom

[Bo_Beck]

ratagonia wrote:
Except that Hubert's calculations are a model of the system, and Sonny's measurements are for one particular system, so take them as an indication, not a law.

Highest forces are found at the very bottom of the guideline, when the rappeller's weight is 100% on the guideline, and the guideline is as flat as possible - in other words, just before the rappeller touches down or drops into the pool.
Tom

And once again it depends on the angle of the Guiding Line. If it is 20 Deg from horizontal then it is a sloping highline and highest force moves substantially closer to midspan. Even with a sloping highline under enough tension and a 1kn rapeller it would be possible to progress very close to the bottom anchor on rappel. My point is that if it requires 2 people on a 3:1 to get the person over an obstacle the forces generated might be a bit overkill for a canyon setting with unfamiliar anchors. I believe that practice should be done as well, but I stand firm with what I said before...If there is failure of the guide line, what are the consequences? Keep the load at a safe distance to the wall until it is absolutely necessary to tension the guide line. Not only is it safer, but it is much harder to accidently overtension the guiding line. If the rappeler gets to the bottom and it requires 4 people on a 3:1 to get him over the obstacle then you'll have an idea as to the force the anchors are seeing had it been pretensioned with just one puller. An average person can generally pull 50 Lbs without slipping the rope in their hands (the average). That means that on a 3:1 a person can pull 150 Lbs of force x 4 people is 600 Lbs or 3 KN. Get a bounce or two as the rope is tightened and increase that force a bit? Maybe 4-5 KN? Whats the point? To stay dry or stay alive?

[rcwild]

Bo_Beck wrote: Whats the point? To stay dry or stay alive?

Exactly.

In Tom's Das Boot story, the guided rappel could be justified only because Karen was hypothermic. Can't comment on whether or not it actually helped her. Lesson from the experience should be about the drysuit.

I stand by my earlier comment that people are over-using guided rappels just because they seem cool.

There is nothing in Water Canyon that warrants a guided rappel. So it's done just to impress clients and to have more fun. That's sending the wrong message to those clients and to the canyoneering community at large.

News flash ... sometimes canyons have water in them. Go prepared to get wet.

Tom, I'm the guy who taught you how to set up guided rappels - for very specific situations like avoiding dangerous hydraulics. Bothers me that you are promoting an advanced technique for situations where they are not warranted. Someone is going to get hurt.

[tanya]

ratagonia wrote:

While Rich may find it silly to guide rappels in Class B canyons "to avoid a little puddle", I find "IT DEPENDS". The only way to maintain skills and understand rope skills is to practice them, so then they are needed for rescue or to avoid hypothermia (or to avoid potholes, or to have MORE FUN), or to allow Tanya from getting wet (obviously, a HIGH PRIORITY if I've ever seen one), then perhaps they are not silly.


Tom


Oh yeah! :2thumbs: :five:



Thanks to the Bushwhacker for keeping me out of the water on Saturday! It would have been so COLD :cold: --- and it sure made the canyon more fun for me!

[Bo_Beck]

rcwild wrote: I give up.

Have fun. Safety is optional.

I don't give up at all! I think that this forum is for people to gather information, evaluate the information and then apply the information the best they know how to. I don't have anything against guiding lines, single rope technique, pothole escape methods etc. etc etc. , but would hope that all the facts and possibilities can be laid out on the table before someone opts to try them blindly. I know that I certainly don't have all the answers, but from my experiences I try to relay what I've been taught and put forth concerns that I personally have. The concerns may or may not be substantiated, but Hell! It's fun to kick around ideas and see what else may be there! :2thumbs:

The guiding line that we used in Telephone Canyon was perfectly safe or I may have made a call to not use it. The angle of the Guide was probably 75-80 Deg and required only a minimal tug from the bottom to clear the pool. I would refer more to the system as a "Tag Line" vs a Guided Rappel. Cool stuff! and it kept Tanya dry...thats what matters!

[Brian in SLC]

Anyone seen the climbing video Masters of Stone 5? Has a part in it where the kids are tensioning a "slack" line and they bust a big locking carabiner. Pretty sobering!

Edited to add....folks with long hair that isn't tied back usually only get their hair caught in their rappel device one time...

Cheers,

-Brian in SLC

[tanya]

Brian in SLC wrote: Anyone seen the climbing video Masters of Stone 5? Has a part in it where the kids are tensioning a "slack" line and they bust a big locking carabiner. Pretty sobering!

Edited to add....folks with long hair that isn't tied back usually only get their hair caught in their rappel device one time...

Cheers,

-Brian in SLC

I have got it caught a couple of times, but actually the worst was when my whole braid was caught, but even so I usually try and keep it back. In this canyon, like most, I started out the canyon with it back, but things happen along the way. If it's a long rappel I make sure it's always back, but short ones not so much.
Start of canyon with hair back...

http://www.bogley.com/forum/viewtopic.php?t=11868&start=0

[Jaxx]

Wow, what awesome responses! Nice link Rich, very detailed info. I would have never thought that the forces could* get up to 2000%!!!!! I have never set up a guided rap in the canyon and this is why I asked. You guys exceeded my expectations. Thanks for all the input. I will definitely be more careful when considering a guided rappel. Someday I will get to some ACA classes and get properly trained :2thumbs:


*with the right angles,weight,conditions,etc.

[ratagonia]

Jaxx wrote: Wow, what awesome responses! Nice link Rich, very detailed info. I would have never thought that the forces could* get up to 2000%!!!!! I have never set up a guided rap in the canyon and this is why I asked. You guys exceeded my expectations. Thanks for all the input. I will definitely be more careful when considering a guided rappel. Someday I will get to some ACA classes and get properly trained :2thumbs:

*with the right angles,weight,conditions,etc.

The calculations assume an infinitely stiff rope. In the real world, when the loads get high, the rope stretches some (even stiff static ropes stretch some) which tends to decrease the loads. So, hard to get 20X. If you want to, use steel cable.

You can also take a class from ME (through Zion Adventure Company 435-772-0990) and get yourself properly trained. Available anytime. More fun if you get together a bunch of people.

Tom

[Jaxx]

Thanks for the info guys!

[Bo_Beck]

If you make the "guiding Line" quickly adjustible you can have a lot of fun with the rapeller! Like "dip-em'" in the drink!
:roflol:

[Bo_Beck]

Just thought a lesson in proper rigging for the tensioning system for a guided rappel was in order! :lol8:

[Bo_Beck]

rcwild wrote:
If an instructor is going to give advice about advanced techniques on the internet, he should consider the audience and error on the side of caution - like Bo did.


I learned long ago that I love my friends. These folks at Bogley are my friends! (no I don't want a Kiss Shane :lol8: ) and, rather than belittle or assume that they are ignorant, I prefer to present ideas and kick them around with them. I don't have the answers to all the "tech stuff" but feel that I certainly have some ideas to bring to the table. After kicking ideas around, hopefully facts brought forth will prevent one of my friends (or me) from making a mistake that ends up in injury or death. Yes....it's all about having fun and making light with conversation, but we all should be respected for our beliefs and contributions.

[Jaxx]

Since I still cant find the cable to my camera I just drew a picture. I know that I could have typed in all the words but I think it looks funnier when you just write it with the pencil. It kindof looks like a 2 year old drew it.

One way (as suggested by Bo) to make my setup better and monitor the slippage is to add a figure eight to the end of the rope instead of a half-hitch and connect a prusik to the guide line so that if a certain amount of pressure is on the rope it will slip. Would that work?

Give me some critisism on this setup, call me stupid, newb, amatuer. I can take it! :haha: Ways to improve or things that are correct?

[ratagonia]

Jaxx wrote: Since I still cant find the cable to my camera I just drew a picture. I know that I could have typed in all the words but I think it looks funnier when you just write it with the pencil. It kindof looks like a 2 year old drew it.

One way (as suggested by Bo) to make my setup better and monitor the slippage is to add a figure eight to the end of the rope instead of a half-hitch and connect a prusik to the guide line so that if a certain amount of pressure is on the rope it will slip. Would that work?

Give me some critisism on this setup, call me stupid, newb, amatuer. I can take it! :haha: Ways to improve or things that are correct?

Why you stupid, newbie amateur!!!! (feel better?) :twisted:

Yeah, kinda. Don't become overly fascinated by the need to tighten the Guided Rappel. It depends on the geometry and the anchors, but guided rappels do not often need to be supertight. Often, one person pulling on the rope and another setting a biner block tight to the anchor is all it takes. You have set up a mechanical Advantage system with pulleys, so can produce quite a bit of power on this end. You would do better to put in a second butterfly loop higher up, put a biner on it and hitch the rope off to that (perhaps with a munter-mule). Rope on Rope can produce problems, including putting a glitch in your rope when you snug it up.

I find pulleys not real useful in this context. The friction of rope on biner helps when snugging it up.

Also, for all but the last person, the rappel line could/should be clipped up separately to the top anchor. Last person converts to "retrievable guided rappel". (This puts less stress on the bottom anchor).

Tom