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seniormoose
Nov 18, 2011, 4:57 AM
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Registered: Oct 24, 2011
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I’ve been giving a lot of consideration to the issue of how to switch from ascender to descender while on top rope self-belay. Here’s what I’ve come up with (with the advice of others on this forum). First, I tie my rope to the anchor’s master point biners (using an Alpine butterfly or figure eight) so that I have in effect two parallel ropes hanging down to the ground. To ascend one of the ropes, I use a Petzl Microcender. Until recently I was using a Petzl Shunt, but the Microcender has less drag and also is safer. I do not attach a carabiner to the Microcender. Instead, I take a 24” Dyneema sling and girth hitch it to a biner attached to the tie-in loop on my harness. Then I pass the sling through the hole in the Microcender where the biner ordinarily goes. Then I take the sling back to the biner, wrap it around it two or three times, then pass the sling through the Microcender, then wrap around the biner two or three more times, and finally I push the end of the sling a third time through the Microcender hole. (It will go through if you push hard.) Then I attach a biner to the end of the sling, so that it doesn’t accidentally slip back through the hole. The object is to tie the Microcender snug to the biner. While climbing, if the connection between the Microcender and the harness (via the sling) is snug, if I fall, I only fall a couple inches. To prepare to switch to descend, I run the rope through an ATC a few inches below the Microcender and then clip the ATC and rope loop to a biner on the harness’ belay loop in the usual manner. I also tie a back-up autoblock to the rope below the ATC and clip it a leg loop in the usual manner.
With the above done, I’m ready to switch my weight from the Microcender to the ATC. I hold the brake line below the ATC (but above the autoblock) with my right hand in the usual manner. Then I use my left hand to unclip the biner from the end of the sling, and I put the biner on a gear loop. Then (again with the left hand alone), I push the sling back through the hole on the Microcender, unwrap it from the biner, then push it back through the hold on the Microcender again, etc. until the Microcender comes free of the biner and the sling is hanging between my legs. At some point during this unwinding process the weight gradually shifts to the ATC. The entire transfer from Microcender to ATC shouldn’t take any more than five minutes if it goes as planned. It can be done even while hanging in mid air. Then I rap down, guiding the Microcender down the rope with my left hand if it won’t come on its own.
Note that I don’t extend the rappel with a sling because to do so would mean a fall the length of the sling after the weight comes off the Microcender until it goes on the ATC, thereby shock-loading the sling. With the recommended set-up, the fall during the transfer should be no more than a couple inches. What I like about this system is that I don’t need to unweight the Microcender by standing on a foot loop, a procedure that I fear I might not be able to accomplish in a critical situation, especially if I’m fatigued. I also don’t need to tie off the ATC with a mule at any point.
For a back-up while ascending, there are two options. One is to tie a loose friction knot (e.g., a Kleimheist) above the Microcender and attach it to the same biner or another one, but with adequate slack so that the Microcender, not the friction knot, is taking the weight. (If I do this, I carry a razor blade in a small box in my pocket in the unlikely event that the friction knot winds up taking my weight and I can’t unweight it to make the transfer). The better back-up IMO is to tie loops in the parallel rope at periodic intervals with either an Alpine butterfly or a figure eight (I prefer the butterfly) and use two quick draws. As I ascend, I attach one quick draw to a loop. Then when I get higher, I attach the second quick draw to the higher loop and remove the first quick draw from the lower loop, etc. Some dispense with this, but I think it’s the ultimate safe back-up. (Don’t forget to unclip from the knot before rappelling.)
When I have a chance, I’ll post a picture.
Comments from others would be appreciated.
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dr_feelgood
Nov 18, 2011, 5:06 AM
Post #2 of 7
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Registered: Apr 6, 2004
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I use the two ropes method.
Ascent: Basic Ascender on top with webbing chest harness to keep upright. Minitrax on bottom as backup.
Changeover: Unclip ascender from chest harness. Put grigri on rap rope. Unclip minitrax. Weigh grigri. Undo ascender. Rap.
Wash rinse repeat.
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tower_climber
Nov 18, 2011, 5:25 AM
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Registered: Aug 25, 2010
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Forgive me for missing the discussion that led to this idea, but it seems rather complicated.
Is there a major pressing issue that is keeping you from buying an original GriGri for TR soloing?
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seniormoose
Nov 20, 2011, 4:01 AM
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Registered: Oct 24, 2011
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Agreed. That was my mistake.
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mikebee
Nov 20, 2011, 4:53 AM
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Registered: Sep 16, 2006
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I too TR solo with the rope tied to the master point with a fig 8, so I have two parallel strands, my set up sounds more simple and I would imagine, much faster too.
- Petzl basic, bottom clipped to belay loop, top clipped to chest harness.
(If you're worried, add a prussik above the basic incase the basic cuts the rope, but really, if you're doing it right, that shouldn't happen.)
- At the top, grab the other strand, put a Gri Gri onto it and clip to your belay loop.
- Feet push up off wall, one hand pulls up on master point, other hand pulls slack through GriGri, the basic is now unweighted.
- Remove basic and abseil down on GriGri.
If nothing else, swap to a GriGri instead of the ATC with prussik backup, it's way faster and easier in every respect.
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seniormoose
Nov 20, 2011, 11:14 PM
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Registered: Oct 24, 2011
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Thaks for your thoughtful comments. I couldn't descend down the other rope because it has the safety Alpine butterflies tied in it every five feet. But I suppose I could use a GriGri on the same rope as the ascender and just below it.
Does your comment mean that you never use an ATC to rappel, but always a GriGri? How does this work with the GriGri 2? Is it posible to manipulate the lever so as to achieve a smooth and safe descent?
(This post was edited by seniormoose on Nov 20, 2011, 11:15 PM)
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