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I'm using a rappel extension similar to what is shown in this video and that one. When the rappel start is a straight drop-off from a ledge and the anchor is low to the ground, I find it difficult to start the rappel as shown in FotH 9th ed. p.216 (description below) as my ATC (tube-type breaking device) often gets stuck above while I lower into position below the ledge and weigh the rope. An obvious solution to this would be to forego the extended rappel and clip the ATC directly to the belay loop and clip the autoblock on the leg loop but I'm not a big fan of the leg-loop approach. Is there a way to start straight drop-off rappels using an extension without getting my gear stuck above?

As to the technique described in FotH:
Essentially the procedure it describes for steep ledges and/or low anchors is to 1- sit down on the ledge as though sitting in a chair; 2- start to rotate to your left until you're facing the rock (assumes right hand is brake hand). This works much better when you can find decent footing. They call the technique is called 'sit-and-spin'.

As to how the ATC gets stuck:
It means that most of my body is over the ledge and the rope is weighted but my ATC, due to the extension, is still on top of the ledge. Given the rope is weighted, it is difficult to make the ATC pass the over the ledge.

  • Could you elaborate on what you mean by your ATC getting stuck? I extend my rappel but this does not happen to me so we must be doing something differently. – Qudit Jun 3 at 1:10
  • What I can imagine is, that if you are below the ledge edge and your tuber on the extension is still above, the tuber, rope and everything get crammed against the wall, making it hard to move. Also FotH seems to be sort of a bible in certain regions, but please don't forget that it isn't common knowledge everywhere. It would be nice if you could describe the important points displayed in that section (currently I just assume it to mean the usual procedure to lean back with feet apart and start walking downwards once in a leaned back position). – imsodin Jun 3 at 7:54
  • @imsodin good point about FotH. Essentially the procedure it describes for steep ledges and/or low anchors is to 1- sit down on the ledge as though sitting in a chair; 2- start to rotate to your left until you're facing the rock (assumes right hand is brake hand). This works much better when you can find decent footing. They call the technique is called 'sit-and-spin'. IMO, the lean-back-with-feet-appart technique you describe is very hard to achieve when you have a steep drop-off (pure horizontal to pure vertical) with anchor at ground level. – BobJ Jun 3 at 23:24
  • @Qudit: it means that most of my body is over the ledge and the rope is weighted but my ATC, due to the extension, is still on top of the ledge. Given the rope is weighted, it is difficult to make the ATC pass the over the ledge. What I'm been doing is to try to keep the ATC closer to me as I transition over the ledge by putting some slack in the extension. I cushion the transition by holding the rope with my brake hand as tight as possible but because it has my full body weight on it momentarily, that often leads to some small anchor shocking and/or awkward start when the rope becomes loaded. – BobJ Jun 3 at 23:34
  • @BobJ I see. How much are you extending your rappel by. If it's a lot, that could be the problem. – Qudit Jun 3 at 23:59
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Don't extend your rappel too far

If your extended brake device gets stuck above the ledge, you probably extended it too far. This might also lead to problems if you have to pass a knot or otherwise need to reach up to your device. Tie up your extension sling to get a length that works.

Rappell over the ledge, don't crawl

Another thing that might give you problems is if you try to "crawl over" the ledge instead of fully comitting to a rapell from the start. Stand on the edge. Check everything one last time. Lean back over the edge until your feet are in the same position against the wall/edge as while rapelling.

By now your device should surely have cleared the edge.

Caveat: This does not work with a low anchor close to a sharp edge. (The angles involved would create a huge force multiplier) avoid such anchors unless you have no other choice.

  • As per your suggestion, I used a single-length sling with a larger biner instead of a double-length sling for my extension and this creates more than enough separation between the ATC and the auto-block. – BobJ Jun 4 at 0:08
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    Also, I agree with the idea of leaning back over the edge but only when the anchor higher. When the anchor is low (ground level), this creates a crazy amount of force on the anchor as shown here: bogley.com/forum/…. – BobJ Jun 4 at 0:15
  • @BobJ It also depends on how far from the edge the anchor is and how sharp the edge is. – Guran Jun 4 at 7:06
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    @BobJ The length just has to be longer than your backup prusik sling (or whatever you are using), point being that it must not get stuck in the breaking device or pushed down by it, thus preventing it from tightening and stopping you. I usually use a 120cm sling where I make a knot at a suitable length. The breaking device goes into the loop close to the harness and another biner for self-arrest into the long part - just as an idea. – imsodin Jun 4 at 8:44
  • @imsodin yeah that’s how I do it too. – Guran Jun 4 at 9:04

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