how-to: tie off atc-xp, low stretch rope

[miro]

I have a question about proper technique of tying
off and releasing a rappel device, especially on
a low-stretch rope:

Let us assume I use an ATC-XP on 8mm Canyon Pro,
and I practice a transition from ascending to
rappeling, or some other situation in which I
need to lock-and-unlock my rappel device.

Question A:

Is there a reason not to use just a leg-wrap to
stop my device during the transition?

Question B:

When I tie off an ATC-like device with a mule just
above the device, I don't see how I can release it
without having a short length of the rope going
through the device very quickly, thus effectively
falling a short distance. This shocks the rope and
anchor, and the resulting forces on the rope and
anchor as well as the effects of rope going over
edges are surely significantly larger than those
while in smooth rappel. The shorter the distance
from the anchor the worse, of course. This must be
avoided, especially on a rope like 8mm Canyon Pro,
right? So, what am I doing wrong? How to release
the device in a smooth manner?

Question C:

Is there any other/better way than leg wrap or
a knot above the device?

Cheers!
Miro Kolesik

[ratagonia]

Let us assume I use an ATC-XP on 8mm Canyon Pro,
and I transition from ascending to
rappeling, or some other situation in which I
need to lock-and-unlock my rappel device.

Question A:
Is there a reason not to use just a leg-wrap to
stop my device during the transition?

A leg wrap is simple and effective. Clipping the rope in somewhere after the leg wrap to keep it from falling off is important to security. The only problem I have with a leg wrap (other than the pain) is that you then must hold your leg in the position, or you will slip lower. Can be hard to use a foot loop and not move your wrapped leg.



Question B:
When I tie off an ATC with a mule above the device, I don't see how I can release it without having a short length of the rope going through the device quickly, thus falling a short distance. This shocks the anchor, and the forces on the rope and anchor, and the effects of rope going over edges are surely larger than those while in smooth rappel.

This must be avoided, especially on a rope like 8mm Canyon Pro, right? So, what am I doing wrong? How to release the device in a smooth manner?

A mule ABOVE the ATC is very ineffective. Don't do this. And, yes, in general you should avoid shock loading your rope by dropping whatever distance.



Question C:
Is there any other/better way than leg wrap or a knot above the device?

Cheers! - Miro Kolesik

YES, there is.

But first, why a mule above an ATC is bad: The main friction in an ATC system is when the rope comes DOWN over that final edge. You defeat this if you lift the brake end up parallel to the upward strand, and are then eventually hanging on the rope through a biner. At which point you will most likely fall to your death. We discourage this behaviour.

Tying off an ATC (Practice this at home)

First, best if the ATC is set up with "enough" friction - enough meaning that the rappel is easily controlled with a light grip of the brake hand.

Second, stop. Pull the rope down tight. Take your left hand (assuming you rappel right) and grasp the ATC and the brake side of the rope, and squeeze tightly. By squeezing the brake strand tightly to the ATC, you will lock it off. (This frees up your right hand.

Third - poke a bight of the brake rope through your BELAY loop. Pull through about 2 feet. (The bight goes through right to left).

4. Tie the bight off to the rappel carabiner. The easiest way to do this (but not the easiest to describe) is to take the bight back across in front of you (left to right), then behind the belay biner and through it from behind. Run this bight BELOW the strand in front of you and pull snug. Then put another half-hitch in above this.

(Tech Tip with pictures forthcoming on the CUSA site, but don't hold your breath).

5. You can then let go.

Practice this at home until it A. Makes sense and B. you can do so hanging from the rope, without losing height.

This is NOT tied with a mule, but is a hitch that can be untied while weighted. It helps a lot that the ATC friction device is still used 100%, and the wrap through the belay loop (rope on webbing) adds a lot of friction to the system.

Tom

[rcwild]

Another option ...

1. Hold your hand down in brake position and reach through your carabiner with a couple fingers from your non-brake hand. Use those fingers to pull a bight of rope through the carabiner.

2a. With practice, you can tie a mule with that bight on the backbone of the carabiner.

2b. May be easier to pull that bight up and tie a mule on the rope above your rappel device. When you pull up, you are using the carabiner and rappel device as a pulley, maintaining the brake.

3. If you are going to be hanging out for a while, back up the mule with an overhand knot on the rope above your rappel device.

MULE HITCH CAUTION: Because the mule is releasable under tension, you should not rely on it as your sole security when tying off. The weight of the rope hanging below you may be enough to untie it.

LEG WRAP LOCKOFF: The only problem I have seen with leg wrap tie-off occurs with some knot-passing techniques. Leb wrap uses too much of the rope. Shouldn't be a problem when transitioning.

[miro]

Thank you Tom and Rich!

Hm, I was doing the mule above atc by pulling the rope
through the biner first which kept my atc in the breaking
mode... If I understand, it is (1. + 2.b) in Rich's
description. The problem was to get going again, because I
had no space on the rope to keep it under tension while
removing the mule. Maybe (1. + 2.a) is better w.r.t. that
problem, i.e. I could use left hand to squeeze rope and
atc tight as Tom describes it in his point 2, and remove
mule with right hand? I will try and practicde both Rich's
(1. + 2.a) and Tom's algorithms and see... Unfortunately I
am at work, and can't try it right know ;-)

I just wanted to ask for a little clarification of Tom's
algorithm for the case I use alpine bod harness (i.e. no
belay loop). I use a loop girth-hitched to the harness and
clip the biner in the loop. Question: It is this loop that
should play the role of the belay loop in your
description. Is that correct?

Thanks again!
Cheers,
Miro

[ratagonia]

Thank you Tom and Rich!

I just wanted to ask for a little clarification of Tom's
algorithm for the case I use alpine bod harness (i.e. no
belay loop). I use a loop girth-hitched to the harness and
clip the biner in the loop. Question: It is this loop that
should play the role of the belay loop in your
description. Is that correct?

Thanks again!
Cheers,
Miro

Uh, no. You complicate things by having non-standard equipment. Perhaps I could suggest getting a new harness, one with a belay loop?

A loop girth-hitched to the harness tie-in points is not a substitute for a belay loop. The belay loop is both more-functional and more durable because it is a double layer wrap.

Tom

[beadysee]

Uh, no. You complicate things by having non-standard equipment. Perhaps I could suggest getting a new harness, one with a belay loop?
A loop girth-hitched to the harness tie-in points is not a substitute for a belay loop. The belay loop is both more-functional and more durable because it is a double layer wrap.


I've got a pretty big pile of self rescue and how-to books. I've never seen one that suggests tying off the belay loop. Almost all are either on the biner spine, or, under the biner and back on top of the ATC type belay/rappel device. Not saying its not a good idear, but, doesn't appear to be "vetted" by anyone. Have you got a source for this method?

I think the easiest way to tie off an ATC whilst loaded is if you start with a munter on a biner on the leg loop. Pretty easy to just mule knot off of that munter, and, you never release the brake. Also keeps the rope below the ATC and easy to load, unload.

I've used the "under the biner and around the top" tie off with a loaded ATC to practise escaping the belay. Takes some care to not release the load in a rapid manner, but, I find it pretty easy to manage with practise.

Another method a friend uses is called "the bubba hitch". He ties a clove hitch around the rope above the ATC. I've tried this and it seems to work pretty well. See here:

www.rockclimbing.com/photos/Misc/Tying_the_Bubba_Hitch_26372.html

-Brian in SLC

[Turtle]

The problem was to get going again, because I
had no space on the rope to keep it under tension while
removing the mule.I prefer passing the bight through the belay loop for this very reason.

After passing the bight, there will be a short downward run of rope (about one carabiner length) between the ATC "exit" and the "entry" into the belay loop. This length of rope is significant upon untying, as it's long enough to allow grabbing with your entire (right) hand.

In contrast, if you pass the bight through the biner, there is only a very short run of rope. I find I can't grab it, and inevitably wind up dropping a bit upon untying. Though I've not become comfortable with the "squeeze" technique that Tom describes.

[catware11]

I use my Petzl 'Canyon' harness for canyoneering. It does not have a belay loop. But I do not think it is an unstandard piece of equipment for canyoneering.

[charlybldr]

In contrast, if you pass the bight through the biner, there is only a very short run of rope. I find I can't grab it, and inevitably wind up dropping a bit upon untying. Though I've not become comfortable with the "squeeze" technique that Tom describes.


This is a learned technique and easy to perform once it is mastered. Just takes a little practice. The "squeeze" technique is important because that's what holds you in position on rope.

With the left hand "squeezing" to hold yourself in place it is fairly simple to push a bight of rope through the carabiner with your right hand (I use my thumb) and give it a twist to creat a loop. I then simply reach back through the loop (with the same right hand), grab the tail of the rope, pull it through the loop and voila... I've tied a mule knot.

Pull enough rope through to make a safety loop, clip this loop back to your harness and you're good to go.

Easy to do with a non-standard canyon harness too;) .

[mtngoat59102]

In short, the ATC is not as straight forward to tie off under load as some other devices. However, it can be safetly done with practice and proper technique. We all like different things but this is a good point to consider in gear selection and recommendation.

[ratagonia]

I've got a pretty big pile of self rescue and how-to books. I've never seen one that suggests tying off the belay loop. Almost all are either on the biner spine, or, under the biner and back on top of the ATC type belay/rappel device. Not saying its not a good idear, but, doesn't appear to be "vetted" by anyone. Have you got a source for this method?


Ah, an Ad Hominem argument. How.... charming.

http://en.wikipedia.org/wiki/Ad_Hominem

I am the PRIMARY source on this technique, thus, less reliable, as
noted by Brian, than a reliable SECONDARY source. See:

http://en.wikipedia.org/wiki/Wikipedia:Reliable_sources

If you do not consider me reliable as a Primary source, than you
should not use this technique. If you DO consider me reliable as a
primary source, you should STILL try it at home (ie, in a controlled
environment), understand its limitations and evaluate its weaknesses
before using it in field conditions.

By running the brake-hand rope down and through the belay loop, the
nylon on nylon interaction creates substantially more friction than
passing it through a carabiner, making tying it off (and releasing
it later) substantially easier. The rope is then tied off as a
bight to the belay biner or above the device, and safetied, NOT
directly to the belay loop.

LIMITATIONS: the rope on webbing interaction provides substantial
friction, decreasing the tension on the opposite side. BUT, if one
lets the rope slip even a little bit, while under tension, the rope
on belay loop friction could put a "ding" in the belay loop, which
could result in immediate or future failure. The "ding" would also
be on the inside of the belay loop, which on Black Diamond harnesses
is the most important section of webbing (other brands may be
constructed differently).

Obviously, photos would help explain the details.

Tom

[ratagonia]

I prefer passing the bight through the belay loop for this very reason.

After passing the bight, there will be a short downward run of rope (about one carabiner length) between the ATC "exit" and the "entry" into the belay loop. This length of rope is significant upon untying, as it's long enough to allow grabbing with your entire (right) hand.

In contrast, if you pass the bight through the biner, there is only a very short run of rope. I find I can't grab it, and inevitably wind up dropping a bit upon untying. Though I've not become comfortable with the "squeeze" technique that Tom describes.

If you SUSPECT you will be tying it off, extending the rappel device with another (locking) carabiner can be helpful, providing that extra length that can be helpful in getting back on rappel without slipping. Doing "the pinch" on the way out can also be helpful.

Tom

[beadysee]

Ah, an Ad Hominem argument. How.... charming.

If you do not consider me reliable as a Primary source, than you
should not use this technique. If you DO consider me reliable as a
primary source, you should STILL try it at home (ie, in a controlled
environment), understand its limitations and evaluate its weaknesses
before using it in field conditions.


Wasn't intended that way, nor constructed that way.

A quick perusal of the literature reveals at least four sources for self rescue and climbing how-to that all show how to tie an ATC device off, none of which use the belay loop. I'd think these folks would have considered a belay loop as a possibility, and that they didn't makes me wonder why you promoted the techinque, which had nothing to do at all with your character (although we could all agree on you being a "character").

Nylon on nylon movement is a bad idea. Releasing a mule knot might not promote much damage, but, it could. I'd think for that reason alone its a technique that isn't promoted by rescue folks or climbing how-to books.

Has nothing to do with your character, feelings, insecurities, prejudices, political affiliations, sexual preferences, type of food you like to eat or any of that. Was just pointing out that you alone seem to be promoting a technique that isn't "vetted" by the self rescue (or rescue community, as its also not promoted by SAR books as well) or how-to type books. You've gone on to explain the technique is nylon on nylon which has more friction. Also why maybe its not such a good idear.

For instance, you lock off the ATC in a free hang with one hand. Other hand runs the rope through the belay loop, which you tie into a mule knot and back it up with an overhand knot. You do your tied off business, whatever that may be. You go to undo the overhand, and note that the mule knot has bound up and is difficult to untie. You transfer your brake hand into the fray to aid in undoing the mule knot. You've also pulled a large length of rope through this belay loop to help loosen the knot. Mule knot comes untied, leaving your brake hand now on the rope under tension through the belay loop, which, off course starts to slip. Resulting melt through cuts the belay loop, and you plummet to your death.

What would ANAM say? Will be nothing about what type of movies you like to see, or your favorite soft drink. Will say the technique used was inherently unsafe and prone to cause damage to the belay loop. The sacred belay loop.

Todd Skinner, RIP.

Wouldn't be optimal, but, I think you could safely complete a rappel with the rope passing through the belay biner. And, the pass through the belay/rappel biner can be practised over and over and over, with out a worry about having to replace your harness due to a grooved out nylon belay loop. It doesn't create a time bomb.

Cheers,

-Brian in SLC

[heli]

Tom's way makes sense to me.