need rappel advice

I'll chime in here regarding the autoblock and it's importance.
Several years ago a buddy and I were rapping sidways across the top of a slab to get to another rap station. I backed up the "rap" even though we were basically just walking along the slab from left to right. I tripped and wound up taking a 50' pedulum across the slab and over the edge (there was a 40' headwall below the slab) My buddy said all he saw was a puff of chalk after I went over the edge. I was scrapped and a litle bruised but otherwise unharmed because I had backed up my rappel. It's a good habit to get into but to each their own.

Jason Krug wrote:Seems like every time I set up a toprope, get fixed in with an ATC device, with a back-up autoblock, and rappel off the top I start having problems with my rope getting twisted.

You might look at how the rope enters and exits the ATC. It really needs to flow straight through to not twist the rope.

If you hold the rope at a 90 degree angle from how the rope enters the ATC, it'll twist the rope.

Cheers!

dostol wrote:Hey Jason, I'm a noob too, also learning to use the autoblock.... I find that adding another locking biner in lieu of a sling under the ATC is adequate to extend the device past where the prussic will interfere.

Avoid clipping a biner to another biner when possible. Not that there are situations where it might be appropriate, but this really is not one of them.

dostol wrote: Thanks for the caution, and I'm wondering what the rationale is, as I've not read or heard that yet.

This is why:

vimeo.com/30216309

Two non-locking carabiners only need to twist over each others gate(s) to become unclipped. This is far less likely to happen with a sling, and you should really only clip locking carabiners to other locking carabiners if you have to do it at all.

If using a cowtail to extend your ATC away from your harness, you should really clip your autoblock knot into your belay loop, not into your leg loop. Hanging from a single leg loop is awfully uncomfortable.

I recently started to use an autoblock. I was with others that figured it wasn't necessary, and changed my mind.

My questions... what is the minimum diameter cord you can use in this application? I know dyneema slings don't necessarily have enough friciton, but is it ok to use a nylon sling?

I always back up my rappel but do so above the device rather than below. I.ve spend lots of time hanging this way cleaning single pitch trad climbs with no issue. This post makes me feel maybe I should be doing otherwise. Opinions...

nathan mowery wrote:I always back up my rappel but do so above the device rather than below. I.ve spend lots of time hanging this way cleaning single pitch trad climbs with no issue. This post makes me feel maybe I should be doing otherwise. Opinions...

I have started using a Petzl Shunt below my ATC. I have a ~6" sling that extends the ATC out just the right amount, and it makes for a nice easy setup that can be completely hands-free. Both devices are attached to my belay loop.

My only complaint is that it can be tough to get it all situated if I'm preparing to rappel and I'm tied in too close to the anchor; as soon as you start extending things out from your harness you need a little more room to operate and to get everything properly positioned and weighted.

Not sure why some here advise against the autoblock off their leg loop. Always works fine for me.

If you run the autoblock onto the brake rope (i.e., not above the ATC, but below it), then the load is not that great because the ATC friction is helping you. I've hung off this set up and its fine.

So my set up is a 6 inch sling to extend the ATC off the belay loop. And a loop of regular nylon cord off leg loop to autoblock the brake rope.

I finally remembered to take a couple of pictures of the setup that we use-- it's pretty much straight out of the Petzl how-to page:

It's really easy to set up, it feeds smoothly, and it stops on a dime if you release the Shunt and it's easy to disengage the Shunt to start moving again, even if you're free-hanging. The ATC (Reverso in this picture) is extended out about 8" or 1' from the harness so it's still within easy reach if you need to get at it.

I used to just rap without any thought for a backup other than an occasional fireman's belay.

I ended up getting a deal on a Shunt and I'm never looking back! I found that it adds almost zero time to my rappel and addresses a few issues. Firstly, it backs me up in the even I get knocked out of something. It allows me to lock off and take photos, route maintenance or whatever. Also, it's a backup to my belay loop (which is a concern for some) and, I'm not sure if it would have enough time to catch me if I somehow forgot to put a knot in my rope and I rapped off the end but if so it's serving 4 purposes.

When I'm finished cleaning and about ready to unclip my anchors I unclip the first sling (girth hitched through my leg and waist loop) from the anchor and clip it to the Shunt, the second goes to my gear loop like normal and off I go with my hand on the Shunt which works out to about 12-18 inches above my rap device (Omega SBG which I love).

Never rappel without a backup!

Flake out the rope a few times starting on the same end (If you switch end, you're just pushing the twists back and forth).