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Extending Rappel Device with Dyneema?

Original Post
Steven Lee · · El Segundo, CA · Joined Mar 2014 · Points: 385

Hi Guys,
For cleaning a TR anchor, I'd like to try extending my rappel device per the Petzl method below.



or the "guide's choice method" shown on the following site
raggedmountainguides.wordpr…


Reading the posts here, it seems like it makes a lot of sense. You've got a sling girth hitched to the tie in points, a overhand knot in the middle with your rappel biner running through the lower loop (per Petzl) or both loops (per "guide's choice on the Ragged Mountain Guides site", and a final biner hooked on your belay loop.

For the extension, I see most people using a nylon 120cm (48") runner. What are your thoughts on a Dyneema 10mm wide 120cm runner? I think we've all seen/discussed the DMM knot on Dyneema videos. I was thinking that as a rappel extension, using Dyneema with an overhand in the middle should be of little concern. What do you guys think? What about whether or not to clip your rappel biner to just the lower loop (Petzl) or through both loops under the overhand knot ("Guide's Choice")? Thoughts much welcome!
Dobson · · Butte, MT · Joined Oct 2011 · Points: 215

I'm not saying it's a bad idea, but explain to me why it's a good idea. Why is putting the device out of reach with an autoblock better then keeping it in reach?

If you can answer that question well, then it will work well for you.

Jacob Smith · · Seattle, WA · Joined Aug 2013 · Points: 230

I've never understood the point of extended rappel techniques like that. Lots of people use them, but I have yet to see a single actually compelling reason for it.

Marc H · · Longmont, CO · Joined May 2007 · Points: 265

The benefits are:

  • Long hair generally can't get caught in the device (as well as loose-fitting clothes/jackets).
  • An experienced climber can set up inexperienced partner(s); rappel; then give a fireman's belay without having to worry about the inexperienced climbers setting up their own rappel (which is probably the most common use).
  • It puts your center of balance at a higher point which can be useful when rappelling with a load attached to your belay loop (pig/heavy pack/injured climber).

Anytime I do this, I use 2x 60cm slings. I hate using a single Dyneema sling for any non-redundant use.
will ar · · Vermont · Joined Jan 2010 · Points: 290
Dobson wrote:I'm not saying it's a bad idea, but explain to me why it's a good idea. Why is putting the device out of reach with an autoblock better then keeping it in reach? If you can answer that question well, then it will work well for you.
If you plan on using an autoblock for every rappel (which I've observed ~90% of climbers do since moving to the north east-ok maybe that's an exaggeration) it's not a bad idea to extend it. If you get knocked unconscious by rock fall it's possible to flip upside down (even more likely if you have a pack) at which point the autoblock on your leg loop could slide up to the atc and do nothing. If you're not using an autoblock I'm not sure I see the advantage. Some people say that you get better control with an extension, but it didn't seem to make much of a difference to me when I tried it.

PS-if you ever need to rappel with a haulbag it is more comfortable and easier to control the bag if you extend yourself below the clip in point of the haulbag.
Mitch Musci · · Estes Park, CO · Joined Apr 2002 · Points: 665

So far the benefits have pretty much been covered. I have experimented and found that the autoblock rappel backup locks more consistently when the rappel device is extended from the belay loop. Perhaps it is because the rope runs in a straighter line from the rappel device to the autoblock when you have the device extended from the belay loop.

I don't see any issue with using a dyneema sling to extend compared to nylon. Make sure the rope doesn't rub on the sling when rappelling. The DMM tests do not apply to this situation unless you are rappelling on a static line, and even then you would really have to screw something up to snap your dyneema.

Another tip: use the guides choice method, and clip the far end of the dyneema loop back into your belay loop. Now you have a redundant extension.

Greg D · · Here · Joined Apr 2006 · Points: 883

Rappelling mistakes are high on the list of climber accidents and usually fatal. Why complicate it.

In response to some of the comments above:

It does not change your center at all. You are still hanging from the same point on your harness. Your hands are slightly higher and may give you slightly better control of your balance though.

Pre rigging an inexperienced rappeller can be done just as easily without an extension. I do it often.

Auto blocks can be rigged without the risk of them jamming if you have half a brain. Imagine what you can do with a whole brain.

John's points are valid and may give a slight advantage in some areas. But adding additional time, failure points, and complexity to a simple , yet critical situation is just not worth it in my opinion.

Nylon or dyneema, above the knot or below are not the questions. To do it at all is the real question.

Scott Scharfenberg · · Santa Barbara, CA · Joined Jul 2013 · Points: 15

I wouldn't worry about dyneema vs. nylon in a body-weight-only, no-shock-loading situation such as rappelling. Extending the device away from the harness (like up to chin or eye-level) can make holding the brake on longer rappels easier/more comfortable, and can reportedly make it easier to deal with things in a rescue situation.

Zak Munro · · VT,CO, Bar Harbor ME, SLC · Joined Sep 2012 · Points: 345

Buy a Metolius PAS or the similar and avoid the hassle of slings and having to deal with overhand knots and trying to untie it once its been weighted. For single pitch stuff its far simpler.

DesertRat · · Flagstaff, AZ · Joined Jul 2010 · Points: 196

Extending the rappel has many benefits:
1. With the device a little higher it puts the rope in the brake position naturally, which is what gives it the extra control. This is especially important when you are on skinny line, riding the pig, or are just a heavy person to begin with.

2. It sets up very nicely for rapping with a haulbag (riding the pig)

3. It allows the autoblock to attach to the belay loop, the safest point for it

4. It allows you to set up an inexperienced climber on rappel on a multirap descent. The poster above said it is possible without extending. I'm not sure what that would be if the person were to be able to remain tied in while you rapped.

5. It gives you a tie-in for when you arrive at the next rap station.

Besides the extra 20s it takes to set it up, the only drawback I have found is that when I am in a situation where the rap anchors are near the edge and I have to lower myself over an edge to weight the rope, the extended rappel makes this more difficult.

When I tie my knot in the sling, I use a figure 8. It unties much easier at the end of the day.

Eliot Augusto · · Lafayette, CO · Joined Dec 2013 · Points: 60
John Marsella wrote: ...Finally, the extended device makes negotiating raps over roofs a little easier, especially for clumsy folks like me ...
I love this. Someone who can balance on a vertical rock face 100' in the air on a defect in the rock face no larger than a pinky finger, with possible wind gusts, calls themselves clumsy.
Ryan Williams · · London (sort of) · Joined May 2009 · Points: 1,245
Greg D wrote:Rappelling mistakes are high on the list of climber accidents and usually fatal. Why complicate it. In response to some of the comments above: It does not change your center at all. You are still hanging from the same point on your harness. Your hands are slightly higher and may give you slightly better control of your balance though. Pre rigging an inexperienced rappeller can be done just as easily without an extension. I do it often. Auto blocks can be rigged without the risk of them jamming if you have half a brain. Imagine what you can do with a whole brain. John's points are valid and may give a slight advantage in some areas. But adding additional time, failure points, and complexity to a simple , yet critical situation is just not worth it in my opinion. Nylon or dyneema, above the knot or below are not the questions. To do it at all is the real question.
I agree with Greg. Rappelling is probably the most dangerous thing that most of us do. It is important that you keep it simple. The fewer steps involved in set up, the better.

In climbing, there are often many different techniques that one can use to accomplish the same goals. Most of the time, the benefits of one technique over another aren't enough to warrant a change. Usually, just carrying on doing things the way you were taught (the way you already know) is the safest option.

Personally, I have never extended my decive. Just never seen the need. And I have rappeled A LOT.
Steve0 · · Unknown Hometown · Joined Mar 2010 · Points: 5

Rapping is no fun so I always use an autoblock, usually a prusik. I extend the device simply to make "working space" while using the autoblock.

edit: extended with a single length runner

Nate Mehlman · · Everett, WA · Joined Nov 2013 · Points: 80

I use it when I'm doing Mptl raps to get down. I keep the proximal end about 4 inches shorter then the distal end of the knot and it allows really rapid switch over at the rap station. I usually use a nylon sling out of habit and I think the knot is abit easier to take out then the skinnier dyneema, although new dyneema is quite slippery so that's a pro. I would not think much about using dyneema when your on rap, it is on a dynamic line, which is the same as a belay device directly into your harness. Also, I never put myself in a position to fall on a sling hard into anything (either nylon or dyneema) because I like my back. The only real negative of the extension is sometimes when I go over a roof, Ill clear the edge and my device won't be there yet and it winds up clanking and scrapping across the rock for a 8 inches or so.

Bottom line though, know your system and be comfortable with what your doing. What works for sally might not work for jill. Climb your own climb.

mountainhick · · Black Hawk, CO · Joined Mar 2009 · Points: 120

This has all been covered before on MP, but this is essentially the method I use for multi raps. Covers pretty much every aspect.

vimeo.com/54302232

The thing I like/advantage to this vs the Petzl diagram is redundancy for the actual rap attachment, clips/doubles back to your harness, and has a double loop for the device.

Your choice of thrid hand. I use a klemheist, autoblock or penberthy. currently using penberthy most often

Advantages: faster on and off anchors when multi rapping, can pre rig everyone and check each other, so arguably safer. Room for third hand with no risk of it pushing up into the rap device/failing.

I don't agree however with clipping a single bolt when reaching an anchor, but that's another discussion that's been beaten to death around here.

And, I use nylon for tethers. Also another discussion, but it isn't more than a couple extra grams. provides better piece of mind and is cheaper.

Rick Blair · · Denver · Joined Oct 2007 · Points: 266

The reasons to do it are well documented above. I started doing it because I bought a Petzl Reverso3 when it came out and that is what the instruction manual said to do. Turned out I like it a lot. I have also put 3 or 4 new climbers on the rope for rappel while I was already on. Huge piece of mind in that situation.

I have learned a lot from simply reading Petzl instruction booklets over the years.

Larry S · · Easton, PA · Joined May 2010 · Points: 872

To answer the OP's question, the loads on the knot should be low unless something goes very wrong, and you have an elastic medium in the system (the rope) so the risks of impact while rappelling are pretty low. Lastly, if the knot slips, it cannot come off the sling. So, I feel the risk there, is pretty small. It does add a weakpoint if you factor 1 or 2 your anchor when your clipped in direct. I would prefer using nylon, but wouldn't be scared of using a dyneema sling.

Another unmentioned advantage of this is technique is rappelling with a load - Extending the device lets you hang the load (heavy pack, Haulbag, injured partner) off carabiner at the device, which gives you the ability to move around unencumbered by the weight of the device. And when you arrive at the next anchor, it's easy to secure yourself and the load.

David Gibbs · · Ottawa, ON · Joined Aug 2010 · Points: 2
polloloco wrote: For the extension, I see most people using a nylon 120cm (48") runner. What are your thoughts on a Dyneema 10mm wide 120cm runner? I think we've all seen/discussed the DMM knot on Dyneema videos.
You're not going to be putting any impact on it like in the DMM videos -- and you've got a dynamic rope in the system. So, not a safety issue. Generally, use whatever sling you happen to have around. In nylon, the knot might be a bit easier to untie when you're done than in dyneema.
Aaron Hope · · San Luis Obispo · Joined Nov 2009 · Points: 341
Ryan Williams wrote: I agree with Greg. Rappelling is probably the most dangerous thing that most of us do. It is important that you keep it simple.
I 100% agree. Don't complicate it. More steps = more chance for error.

Similarly, more components = more chance for failure. When extending your belay device using a dyneema or nylon sling you are substituting something that was made to have no redundancy (a thick belay loop) with something that is meant to have some redundancy, the skinny dyneema sling. I'm not referring to strength characteristics, dyneema is plenty strong. But the belay loop is much stronger when wet or when hot and it is much more abrasion resistant.
Max Forbes · · Colorado · Joined Jan 2014 · Points: 108
Dobson wrote:I'm not saying it's a bad idea, but explain to me why it's a good idea. Why is putting the device out of reach with an autoblock better then keeping it in reach? If you can answer that question well, then it will work well for you.
I almost always extend my repels. Its easy and convenient. The device itself is never out of reach, and the autoblock is attached to a leg loop on your harness so its also easy to access and way out of the way of the device to avoid jamming.

@OP

There are two pretty good reasons not to use dynema in this situation. Often the point of extending the rappel is so that you can easily unclip from the anchor and transition quickly into a rappel. (This is exactly what is shown from the graphic in Petzl's picture). To be honest with you, I do not own very many double length dynema runners. I've worked with IMFGA guides who don't any. The reason is because a factor two fall on dynema is highly questionable. If while in the course off setting up your rappel you accidently come above the anchor, slip and fall, there is a chance that your one lifeline will break, especially if its already knotted. For that reason, I always use nylon double length runners when clipping to anchors.

I use the method petzl describes all the time. It works awesome, especially when cleaning a route. I always used a nylon runner. I have tried setting it up with a dynema double, and it just didn't tie as cleanly, and didn't feel as secure. While I think its HIGHLY unlikely dynema would fail in such a system, I like to stick to the nylon. I think in most situations, its reasonable to be carrying one nylon double. If weight was really an issue I would think you would be ok with dynema, however if weight was that big of an issue, you'd probably be doing a lot of rappels, and in that cause I would want to be using nylon anyways.
Carey S · · Boulder, CO · Joined Apr 2010 · Points: 80

The one scenario in which I consistently extend my device is when rapping with my ropes saddlebagged off either side of my harness. (Generally mostly in high wind situations where dropping rope could lead to complications.) Having the device extended allows for better feeding from both coils and more room to untangle potential snafus.

Guideline #1: Don't be a jerk.

General Climbing
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