Counterbalance rappel as non-emergency technique ?

My partner recently came up with a rappel method that I hadn't thought of. It seemed simple and not exceptionally unsafe. But I have not come across it anywhere online, so I wonder if I am overlooking some horrible downside.

The idea is you rappel on one strand. The top of the strand goes through the rap rings/chains. The end is tied to another rope, which goes down to the lower anchor, where it is attached to either the lower anchor or your partner (who rappelled first, also one one strand, but the strand was fixed to the upper anchor then). So like simul-rappel, except your partner is already down.

Why, you might ask, wouldn't I just rappel on both strands ? Two situations:
(A) 2nd rope is much thinner.
(B) Rappel is 50m, the ropes 70 and 30 (and you don't like passing knots).

I.e., this method is an alternative to Reepschunr (which would also work in both cases).

Advantages:
- no carabiner to get stuck on a ledge
- no possibility of knot pulling through rings (if placed far enough down)

Disadvantages:
- both partners must understand the plan
- 2nd rope must be reliable for body weight
- double load on anchor
- setting up rappel is a pain if the counterweight rope stretches
- more time consuming

Let me be clear - I consider this inferior to Reepschnur in situations where Reepschnur would work. I'm interested in situations where there is something for the Reepschnur biner to get stuck on.

Let me also be clear that I wouldn't mess with this on a long sequence of full-length rappels. But I keep running into routes where most pitches can be rapped with one rope but one or two pitches require two ropes.

Also, I'm not asking about the pros and cons of climbing with doubles or the benefits of having a 2nd climbing rope for emergincies. Those seem well documented on the forums already. I'm only asking if what I described is a resonable alternative to Reepschnur.

Finally, as you might guess, simply pointing out that I'm going to die would not really address the question. However, if you see a way that I could die with this method that I haven't already listed, I very much look forward to having it pointed out.

My feeling right now is that, provided the 2nd rope is strong enough, this method is no more dangerous than simul-rappel (which, while not completely safe, is apparently safe enough to be practiced by many).

In other words, why haven't I heard of this before ?

Serge Smirnov wrote:In other words, why haven't I heard of this before ?

Lack of experience or attention?

On multiple occasions I've used this when I've had to use a cordalette (or two) to make a rappel reach. Getting down from Montezumas Tower in GotG with a 60m is one such example. It's less than ideal because you are trusting your whole life to your partners knot tying abilities, but there are worse things, like getting your biner block stuck half way up an unclimbable face.

Cool!

So I assume you somehow secure the rope at the upper anchor for the first person down?

Similar to a Reepschnur, the first is going to want to keep control of the other strand while they descend. If that gets away from them (wind, snag, etc.), you're sunk.

Beyond that, though, it's a cool idea. I really like the fact that you could carry only the missing amount of rope to do longer rappels (carry a 2nd 30m rope to combine with your 70m rope to do a 50m rappel without passing a knot).

I'm really curious if anyone has heard of this before. It doesn't mean much, but it's new to me.

Alexander K wrote:It's less than ideal because you are trusting your whole life to your partners knot tying abilities

Unless I'm missing something, there's nothing stopping you from tying the extension (cordalette, 2nd rope, whatever) at the top so you can both inspect. If fact, the first could even be completely tied in to the extension so there's literally nothing for them to do except go direct to the next anchor. They go direct while still tied to the off strand, the second removes whatever is securing the rappel strand at the top, pulls through the slack, and goes down on the rappel strand.

Two of the disadvantages suggested I don't see occurring realistically:

- 2nd rope must be reliable for body weight
- double load on anchor

What are you planning to use as the 2nd rope? 5mm accessory cord is still rated to north of 1000lbs breaking strength. Unless the 2nd "rope" is a roll of twine, nonissue. (Cool story time: Friend for the lulz tested this. 6 strands of upholstery twine, it seems, will hold bodyweight. Bounce test not recommended.)

And unless you're descending from some sort of A4 nightmare masquerading as an "anchor," there's no way that anchor load is a factor on rappel. The shear-off strength of a SINGLE new 3/8" PowerBolt is comparable to the MBS of a new 10mm rope.
powers.com/pdfs/mechanical/…
blackdiamondequipment.com/e…

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So that said, I don't see any obvious reason it won't work. I would ask, how much do those annoying pitches miss making it by? Enough that e.g. using an anchor cordelette to stretch the rap by 10-15' won't work?

wfscot wrote: Unless I'm missing something, there's nothing stopping you from tying the extension (cordalette, 2nd rope, whatever) at the top so you can both inspect. If fact, the first could even be completely tied in to the extension so there's literally nothing for them to do except go direct to the next anchor. They go direct while still tied to the off strand, the second removes whatever is securing the rappel strand at the top, pulls through the slack, and goes down on the rappel strand.

I generally don't like having huge loops hanging down as they can easily cause big problems. Still possible to saddle bag and rap while tied to the extension but requires a lot of planning. Often times this is kind of a fly by the seat of the pants maneuver, improvising when you aren't sure what will reach, in such a case you could still tie a biner block from the top if necessary but can't tie the end to your partner, I'd generally trust my partner. It's hard to weight the system while indirect to test it because of all the rope stretch, but it is possible.

To secure the knot on top just tie a figure eight on a bite and clip a locker to the anchor.

Erik Keever wrote:Two of the disadvantages suggested I don't see occurring realistically: - 2nd rope must be reliable for body weight

This is kind of important because with a knot or biner block you can potentially pull with any cord. Ultralight pull cords are popular in canyoneering where paracord or amsteel blue lines 100m long can be used in place of a second rope. I would probably never trust a bend connecting something so thin to a larger rope anyways (regardless of cord strength) at which point you will already have a carabiner in the system and might as well use a biner block. I agree that this isn't really a big disadvantage, you just need to understand the limitations of your equipment to use it safely.

Regarding Alexander K's point that often in such situations you're not sure what will reach... mountainproject.com/v/safel… recommends having the first person be lowered by their partner from above. The person being lowered can extend the free end with slings/cordelettes as needed to give it a few extra feet (assuming the main rope is longer than the pull cord).

By default I don't like the communication requirements of being lowered, but in uncertain-length situations it has the clear benefit that you don't have to guess the mid-point of the system up-front.

BTW, the decision of how the 2nd gets down seems mostly indepdendent of how the 1st gets down - at least before considering time optimization and communication protocol. The only real dependency is that if the 2nd plans to do a counterbalance rappel, it is the 1st's job to make sure the pull cord reaches.

The idea of a 70m lead line with a shorter pull cord is motivated as follows: (1) if the pull cord is thick, reducing its length minimizes the extra weight somebody has to climb with; (2) if the pull cord is thin, its length is related to its propensity to tangle; (3) longer lead line helps in combining pitches on the way up.

Have done similar as mentioned by Serge, et. al.

Know your partner!

I'm with caughtinside. Given the high quality, rating, weight and durability of modern thin ropes there's little rationale for going with any of the corded rappel techniques, especially when weighed against the hassles and nightmares you can encounter with pull cords if they are mishandled in any way. Corded rappel systems in general introduce too much complexity with not enough attending benefits compared to going with two thin ropes.