How to set up a guided rappel

[Jaxx]

Tom's story got me thinking about a question I have had for a while. What is the best way to set up a guided rappel? You have two anchors. How do you get the guided line tight enough that it won't sag. How can you use one rope for both the guide and the rap line?

[jwurst]

Use a simple 3:1 haul system to tension the guide line. It doesn't necessarily have to be super tight, just enough so that the rappeller avoids whatever obstacle you are bypassing.

Single rope? If you mean using two halves of a single rope as separate guide and rappel lines then you need to put in a block at the top anchor for the last person down to still allow the rope to be pulled. In a normal situation where the guide line isn't super tight then the block would be on the guide side. If you had enough tension you wouldn't need a block at all. For it to need to be on the rappel side you'd need to have enough tension to actually raise the rappeller against all of the friction in the system. If that is happening then your guided rappel might be turning into a tyrolean. Make sure that top anchor is strong because there is a lot of force involved.

If you mean rappelling on the guide line--you can't--too much tension. You can use an ascending system to descend the line. If the purpose is only to skip going into a keeper pothole then as an alternative to a guided rappel you might be able to rig a pendulum at the bottom--anchor the rope at the bottom but don't put tension on it. Rappel down even with the exit and then use the tail of the rope to pull yourself over to the anchor. This only works if the rappel is quite a bit longer than the pendulum distance.

[SLCmntjunkie]

I'm smiling right now because I know the answers to your questions thanks to some training and practice some other canyoneers were kind enough to give me last week. I didn't read the story yet, so I don't know the context and I'm certainly not an expert, but I'll give it a shot.

You could use one rope if you isolated each strand, setting a block at each anchor, one on the rappel side and one on the guide rope side. You can tension the rope by setting up a mechanical advantage using a z-rig or other techniques.

[SLCmntjunkie]

I guess I wasn't fast enough

[Jaxx]

ok. That is kinof what I had pictured. I think this weekend I am going to set something up in my garage. I hadn't thought of the pendulum deal. Thanks for the info guys.

[ratagonia]

ok. That is kinof what I had pictured. I think this weekend I am going to set something up in my garage. I hadn't thought of the pendulum deal. Thanks for the info guys.

mmmmm. be careful out there. Here's the warnings:

1. Anchors need to be GOOD. Expect to put 3 to 4X bodyweight on the anchors.

2. Usually, the guideline does not need to be exceptionally tight. Careful adjustment of the tightness will keep the loads on the anchors reasonable.

3. After the first person, usually best to tighten the guide line once.

4. MUST use a static line for the guide side. CAN use a dynamic line for the rappel line. The more static the guide line, the less tight it needs to be.

5. To tighten, can do various things. Rarely is mechanical advantage actually required.

6. Without a block, it does not really work. Try it, you won't like it.

here's the cheesy quick diagram:

[oldno7]

Tom's story got me thinking about a question I have had for a while. What is the best way to set up a guided rappel? You have two anchors. How do you get the guided line tight enough that it won't sag. How can you use one rope for both the guide and the rap line?

Are you sure you want to learn this over the internet.
Lots of options,top tension,bottom tension,retrievable,etc.
A retrievable uses the same criteria as pulling a rappel(need double the rap length in rope)
Lots of options as far as angle,friction,etc. I top tension with just body weight, some may need mech advantage. You can use "meat in a pinch as an anchor.(and so on and so on)

[ratagonia]

Are you sure you want to learn this over the internet.
Lots of options,top tension,bottom tension,retrievable,etc.
A retrievable uses the same criteria as pulling a rappel(need double the rap length in rope)
Lots of options as far as angle,friction,etc. I top tension with just body weight, some may need mech advantage. You can use "meat in a pinch as an anchor.(and so on and so on)

And then, there's the "Throw to the guided rappel" - one of my favorites...

T

[Jaxx]

I set up a guided rappel of of the hitches of my two cars, here is the rundown: I used one static 8mm imlay rope. blocked off one side. The other side I tied a butterfly about 18 inches away from the "anchor" in the guided rap side of the rope. I hooked a biner with a pulley on the butterfly knot. I put that side through a pulley on the hitch back to the pulley on the butterfly. Tightened nicely so I upped the anty and put the rope just through the biner on the hitche and back up to the butterfly and tied a double half hitch behind the butterfly to keep the line tight. It worked very well and only would take about 3 minutes to set up in the canyon once the gear was out of the pack. Since I did it on the hitches of course I couldn't rappel of of them. I do have anchors in my garage ceiling but I was worried about ripping them out. I took a bunch of pics but I can't find the cord for the camera !@#$@#

The question I had was about the bolts for the anchor. How much pressure is on these with that type of setup. I was a little worried about tightening the guide side too tight or with the weight of a rappeler on the other side of the line the pressure would be too much. I guess theres only one way to find out!

Another question. What is the best way to tie off the rope once you get it tight?
I don't mind asking questions or getting answers online because I try it out before I'm in a canyon. Seems reasonable.

[rcwild]

The question I had was about the bolts for the anchor. How much pressure is on these with that type of setup. I was a little worried about tightening the guide side too tight or with the weight of a rappeler on the other side of the line the pressure would be too much. I guess theres only one way to find out!

Another question. What is the best way to tie off the rope once you get it tight? I don't mind asking questions or getting answers online because I try it out before I'm in a canyon. Seems reasonable.

You will find the math here:

http://www.canyoneering.net/forums/showthread.php?t=644

Be extremely careful. Some of the advice given in this thread will get you in trouble. Even if you do try things in your garage first, there are a number of variables that cannot be replicated until you are in a real situation. The answer to your question about the best way to tie off is "It depends ..." In this case on how you rigged the tightening system. If there is something in your tightening system that is releasable, you have more options with the tie-off. If your tightening system is not releasable, your tie-off should be.

[Bo_Beck]

The question I had was about the bolts for the anchor. How much pressure is on these with that type of setup. I was a little worried about tightening the guide side too tight or with the weight of a rappeler on the other side of the line the pressure would be too much. I guess theres only one way to find out!

Another question. What is the best way to tie off the rope once you get it tight? I don't mind asking questions or getting answers online because I try it out before I'm in a canyon. Seems reasonable.

You will find the math here:

http://www.canyoneering.net/forums/showthread.php?t=644

Be extremely careful. Some of the advice given in this thread will get you in trouble. Even if you do try things in your garage first, there are a number of variables that cannot be replicated until you are in a real situation. The answer to your question about the best way to tie off is "It depends ..." In this case on how you rigged the tightening system. If there is something in your tightening system that is releasable, you have more options with the tie-off. If your tightening system is not releasable, your tie-off should be.

We use a "guiding line" periodically during rescue. As a rule what I've been taught is that a guiding line should not be pre-tensioned at all unless necessary to clear an object. Once the person has started down whether by rapelling or being lowered, ideally he (or she) should be in contact with the wall or ground the entire time during descent. The guiding line may be tensioned or detensioned during the descent to insure that the person is never at a critical distance from from what ever it is that they are trying to avoid. If there might be failure of the system this minimizes that chance of serious injury (such as slamming back into the cliff face while suspended 20' out). Just my thoughts on the matter.

[rcwild]

We use a "guiding line" periodically during rescue. As a rule what I've been taught is that a guiding line should not be pre-tensioned at all unless necessary to clear an object. Once the person has started down whether by rapelling or being lowered, ideally he (or she) should be in contact with the wall or ground the entire time during descent. The guiding line may be tensioned or detensioned during the descent to insure that the person is never at a critical distance from from what ever it is that they are trying to avoid. If there might be failure of the system this minimizes that chance of serious injury (such as slamming back into the cliff face while suspended 20' out). Just my thoughts on the matter.

What we call a guided rappel in recreational canyoneering is similar to what I learned in rope rescue courses called a telfer. Telfer has much less force on it than the highlines you are using in Zion, but enough that setting them up should never be taken lightly.

Bo, have you looked at the math in the above referenced thread on the ACA forums? Pretty easy to hit load multipliers in the 800-900% range and HIGHER!

Have fun. Be safe.

[Bo_Beck]

We use a "guiding line" periodically during rescue. As a rule what I've been taught is that a guiding line should not be pre-tensioned at all unless necessary to clear an object. Once the person has started down whether by rapelling or being lowered, ideally he (or she) should be in contact with the wall or ground the entire time during descent. The guiding line may be tensioned or detensioned during the descent to insure that the person is never at a critical distance from from what ever it is that they are trying to avoid. If there might be failure of the system this minimizes that chance of serious injury (such as slamming back into the cliff face while suspended 20' out). Just my thoughts on the matter.

What we call a guided rappel in recreational canyoneering is similar to what I learned in rope rescue courses called a telfer. Telfer has much less force on it than the highlines you are using in Zion, but enough that setting them up should never be taken lightly.

Bo, have you looked at the math in the above referenced thread on the ACA forums? Pretty easy to hit load multipliers in the 800-900% range and HIGHER!

Have fun. Be safe.

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!

[rcwild]

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!

Wasn't referring to Sonny's post. Look farther into the thread for the calculations provided by Hubert Shen (barleywino). His calculations reflect the amount of tension/slack in the rope and show forces at various distances between anchor points.

I share your concerns about the risks. This is another system that people think is cool so they want to use it more often than necessary. Primary reason for rigging a guided rappel is to avoid a dangerous hydraulic in a Class C canyon. The risk presented by the hydraulic outweighs the risks of rigging a guided rappel. Anchors in Class C canyons should by necessity be stronger than normal anyway. Using a guided rappel just to avoid a bit of cold water is a bit silly, especially in Colorado Plateau sandstone canyons where the rock quality and anchors are often suspect.

[Bo_Beck]

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!

Wasn't referring to Sonny's post. Look farther into the thread for the calculations provided by Hubert Shen (barleywino). His calculations reflect the amount of tension/slack in the rope and show forces at various distances between anchor points.

I share your concerns about the risks. This is another system that people think is cool so they want to use it more often than necessary. Primary reason for rigging a guided rappel is to avoid a dangerous hydraulic in a Class C canyon. The risk presented by the hydraulic outweighs the risks of rigging a guided rappel. Anchors in Class C canyons should by necessity be stronger than normal anyway. Using a guided rappel just to avoid a bit of cold water is a bit silly, especially in Colorado Plateau sandstone canyons where the rock quality and anchors are often suspect.

Pretty cool calculations for sure. Really what the figures are telling me is that the "Guided Rappel" is transitioning from basically a "Tag Line" to a "High Line". I understand the concept of using a "Guided Rappel" for class 3 canyons and avoiding hydraulics and see the balance between the risks. I just have some concern of the use of these systems without understanding the physics. I would think that someone trying a guiding line for the first time, it would be prudent to install a single prusik at the "anchored end" with a "belly" to the anchor point. At least this way if they use a MA and don't know how tight the rope is, the prusik will act as a clutch and reduce peak force. A single prusik "8mm" on an 11mm rope will slip at between 3-5KN. If using a 9mm rope then a 6mm prusik will do the trick. In Telephone Canyon last weekend I didn't have Kip tension the Guided Rappel until my feet were at the water. He had no problem getting me up high enough to descend the angle to the shore. It reduced the amount of effort he extended until it was necessary to get me over the obstacle. I don't see the need to be suspended out away from the vertical wall until it is necessary. FWIW

[ratagonia]

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]

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]

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]

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!



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

[Bo_Beck]

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!

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!