Monday, October 10, 2016

Extending Your Rappel

We have talked about extending a rappel in this blog before. However, to date we've been too lazy to make a video on the subject.  This is not the case with Climbing magazine's gear editor Julie Ellison. Julie made a very nice video on the subject of rappel extensions.

Following is the video:



There are a handful of additions that I'd like to make to Julie's notes.

Girth-Hitching the Sling

It is important that the sling is girth-hitched through the tie-in points on the harness. It should not be girth-hitched around the belay loop. This is because a girth-hitch crushes the loop and slowly wears it out.

Some choose to keep a PAS or a daisy chain attached to their belay-loop on a more or less permanent basis. This is very dangerous as it freezes the belay-loop in place, keeping it from rotating. The natural rotation of the gear-loop allows wear to disperse around the loop. When something is permanently girth-hitched to it, all the wear is focused into two places, wearing out the loop faster.  To avoid this, we recommend girth-hitching through the tie-in point.

Redundancy

Julie shows the clipping of the device inside the loop between the harness and the rope. To create additional redundancy in the system (at least while rappelling) it is possible to clip the device into both loops. That way, when you clip the end of the system back to yourself, you have a level of redundancy.

Type of Sling Used (Dynema)

In the video Julie is using a Dynema sling. These slings don't do well in a factor two fall.

A factor two fall could take place when you clip into your anchor above your anchor, and then slip. In tests completed by DMM, Dynema slings did much more poorly than nylon slings.  To see a video concerning this, click here.

Our recommendation is generally to use nylon slings in this application. But if you have to use Dynema, then you should be cognizant of this danger.

Third Hand - Autoblock

Julie shows clipping this into your belay loop, which is the correct place to clip the autoblock. However, many people clip it to their leg-loop when they extend the rappel. There is no reason to do this. If your belay loop is clear, why wouldn't you clip the autoblock to it? It's the strongest part of your harness.

Third Hand - Letting Go

Julie does make one off the cuff comment about how your autoblock will save you if you let go.  Indeed, that is the intent of the third hand. However, if the autoblock is loose or sloppy, it may not engage appropriately. As such, I generally still wrap the rope around my leg or tie a catastrophe knot below the autoblock in order to have some peace of mind when I have to go hands free.

Speed and Efficiency

One thing that was not mentioned in the video is that the use of extended rappels in a multi-pitch setting allows more than one person to clip in at the same time. This can significantly expedite a descent and also allows you to check one another to ensure that everything has been set-up right.

I personally tend to extend my rappels at every opportunity. There are some places where it's not terribly useful or realistic (like in a sport setting), but in trad and multi-pitch settings, it is definitely the way to go...down...

--Jason D. Martin

8 comments:

Gonzalo García said...

A really good video... I share it in my fb... Thanks!! =)

www.climbforever.com

Newman said...

so... the girl in the video explains how to set it up, but never describes a situation in which this system would be useful.

other than simply being a safer method for rappelling, with a backup in case you lose control of the rope, or become knocked unconscious, is there a purpose for this system?

Jason Martin said...

Absolutely.

Please see my comments in the blog.

Here is the quick answer to your question:

1) Speed - more people can set-up at once.
2) Safety - you can check one another.
3) Control - It's easier to control your descent with an extension.
4) Tricks - There are more tricks that you can do (like rope climbing) if you're set up with an extension.

Jason

Tim Page said...

This system also reduces the likelihood that your hair or shirt will get stuck in your device, and keeps your autoblock away from your belay device.

Anonymous said...

The end of the sling can also be clipped into the rope you are going to pull at the bottom of the rappel. (As opposed to just clipping it into your harness) Once at the bottom you will know which rope to pull, the ropes will not be twisted and you will have more chances of a clean retrieval.

Anonymous said...

Any thoughts on her choice of knot in the sling? Would a figure-8 be better, or is it only as good as an overhand in this case?

Jason Martin said...

Good question-

A figure-eight is a bit better because it is easier to take out...

Jason

Anonymous said...

I've played around with this system and feel more comfortable with my belay device extended on a doubled up 48in nylon sling from my belay loop (basket hitch rather than girth hitch)with a figuire eight or BHK to close it. To allow better clearance to my prusik back-up I attach it directly to my harness tie in. I feel the prusik locks better, loosens better, and slides better when released, and it gives me another level of redundency if my belay device fails or if for some insane reason I miss rig. I found the autoblock to slip more and not able to hold my weight alone. I'm also already attached for ascending if needed. Just add another prusik for my feet. With my DMM Couloir harness I tried the sling attached directly to the harness and back-up to belay loop and found that when the back-up cord is loose the biner drops/moves/rotates, etc. then quit often cross loads when the back-up is engaged.

So in summary I extend my ATC-XP off my belay loop with a 48in nylon sling basket hitched and tied in the middle with either an overhand, figuire 8, or BHK depending on how far I want to extend it. I then wrap my prusik cord three wraps around both rope strands below device and attached to both harness waist/leg tie in with a BD Gridloc biner. My belay loop is rated to 25 kn and my nylon sing to 22kn. If I didn't use an extention I would most likely use the belay loop anyway. If I need a tether then I add a separate Purcell Prusik that I have tied up already. Your thoughts.