UKC

Counterbalanced abseil - technical question

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 Osiris 07 May 2020

Hey, this is a question for people who are familiar with/have practiced a counter weight abseil. I'm working on a checklist my own personal reference - I'd appreciate your thoughts. I've practiced this and it seems to work, but I've never had to use it on the rock. I'm particularly interested what MCI trainees are being taught on this.

Applicable conditions:
1. It is easier to descend than ascend.
2. The second cannot be lowered to the ground/ledge.
3. The second is incapacitated.
4. There must be a powerpoint (not built with the rope) and this must be in-reach.
5. The next anchor or ground is <half rope length away (single rope) or full rope length (double ropes).
6. Must not be on a traverse.

Alternative scenarios:
If you are climbing with double ropes and need to descend >half rope length (i.e. next anchor/ground >half rope length away), you will need to abseil to the second*, untie one rope, ascend to the belay, release untied rope, and join the ropes before abseiling in counterbalance. This may necessitate passing the knot (see passing the knot in counterbalanced abseil).

Prerequisite skills:
-Tied off italian hitch
-Releasable prussik (french ‘autoblock’ prussik, prussik + italian hitch tied off, mariner overhand)
-Abseil extension with french prussik
-Escape the belay (transition to italian hitch)
-Rescue spider (rope end or cord)
-Tandem abseil

Cautions:
-Avoid if loose rock present (moving ropes)
-If you cannot reach the ground in the first abseil, is there a suitable anchor below?
-Next anchor must be < half rope length (single rope). If not, unless you’re using half ropes, haul, then either shelter or ascend.
-Tie knot in end of rope

Steps:

1. Escape the belay and transition to italian hitch:
a. Back up and hands free
b. Create powerpoint if necessary (separate to the rope)
c. Releasable prussik on live rope (attached with locker to powerpoint)
d. Italian hitch (locker) on powerpoint (tied off)
e. Weight the prussik
f. Remove belay device
g. Take in slack on Italian hitch and tie off

2.Set up abseil (extended with autoblock) below italian hitch
3.Tie catastrophe knot below autoblock
4.Clip dead rope through a locking carabiner on powerpoint.
5.Remove italian hitch.
6.Get your abseil device close to the powerpoint carabiner.
7.Remove personal anchor / tie in knot
8.Release prussik (leave attached to live rope) and set up as releasable on belay loop.
9.Tie knot in end of rope (if not tied to harness)
10.Remove catastrophe knot
11.Abseil to second** and continue to anchor
12.Back up and hands free
__________________________________________________

13.Build anchor (if necessary)
14.Attach both persons (releasable) to anchor e.g. spider.
15.Remove seconds’ knot
16.Pull rope down
17.Rethread anchor
18.Tie knots in end of rope (if necessary)
19.Remove original abseil setup/prussik (nb you may want to do this after step 14).
20.Setup for tandem abseil
21.Release spider
22.Remove back up
23.Abseil

Repeat steps 13-23 (15 n/a) until grounded.

*Attend to injuries before proceeding.
**You may need to pass a knot, if using separated half ropes.

Post edited at 10:36
1
 Alex Riley 07 May 2020
In reply to Osiris:

Seems pretty much right from a quick skim. A few things I would consider.

if the anchors are out of reach you might need to use a master point on a kleimheist to escape the system, then rebuild a new master point at the anchors.

In an MCI context you need to make a decision about your priorities. Ie if the casualty is unconscious getting to them in order give first aid/maintain airway might precede setting up the counterbalance abseil and will help with the decision for what to do next (are there any potential anchors near the casualty, how much rope do I have, how far is it to the ground). 

 jezb1 07 May 2020
In reply to Osiris:

What Alex said!

There really is no replacement for safely practicing this out on the rock (when we can), funny little things happen to add interest to the scenario. Hopefully by practicing in nice controlled environments, those little things are easy to deal with because you have the head space.

OP Osiris 07 May 2020
In reply to Alex Riley:

Cheers! I didn't think about out of reach anchors - that makes perfect sense. I would definitely descend to assess the patient first if I thought they were injured/unconscious.

OP Osiris 07 May 2020
In reply to jezb1:

Thanks JB. I'll try and get out to practice in a realistic situation (safely) soon.

OP Osiris 07 May 2020
In reply to Osiris:

I've just had a thought: what happens if the second is >half a rope length away? Would you need to haul them up til they were at least half way or would they be raised when you abseiled? If they would be raised, would this still happen if they weighed more than you?

 Alex Riley 07 May 2020
In reply to Osiris:

It’s hard to give an exact answer as each scenario is different. The key in all rescues is  to look at the scenario at hand and match the appropriate techniques. Remember most rescues are improvised because they are unexpected (you would hope!). In the real world you might not have the right equipment, rope length etc... so it’s a case of adapting and improvising. (That said lots of issues can be avoided in the first place by planning ahead).

Sorry that’s not a definitive answer, but It’s never a definitive scenario.

OP Osiris 07 May 2020
In reply to Alex Riley:

No worries. I guess you wouldn't want to recommend something that someone could use in error. Just curious. In the scenario I have in mind, I think I'd probably haul them til they were <half length away and go from there, but of course, it's so hard to imagine every possible scenario, so I'm building my toolbox Thanks!

Post edited at 19:28
 Alex Riley 07 May 2020
In reply to Osiris:

Its good to get the brain going at the moment

One thing to consider if you hoisted in this scenario is that you would only get as far as the next runner above them (assuming its a good runner!). If on half ropes you could tie off one rope and descend on the other to reach them, then come up with a solution to get them to the floor/top.

 meggies 07 May 2020
In reply to Osiris:

Check out the Leading Edge Mountain YouTube channel and the JB Mountain Skills YouTube channel.

Sam is a MCI assessor and Jez is a MCI mentor, so loads of great stuff between them.

Post edited at 22:05
 Will Nicholls 08 May 2020
In reply to Osiris:

An important consideration that I don’t think is listed above is whether or not the abseil is free hanging. The prospect of a rope running over an edge with the weight of two people is serious. 
Daniel Gebel from Edelrid came to PYB and gave an amazing presentation. It was very technical with lots of testing and research. The main thing I took away from it was that as soon as you have 100kg or more on the end of a rope the chance of the rope cutting over an edge increases hugely. The diameter had little to do with this as I remember, it was more the weight. 
With this in mind, counterbalance abseils are potentially really gnarly, I assume an average load would be somewhere in the region of 150kg. Daniel’s lecture prompted a decent amount of discussion and thought at work, and I know that what we teach and how we deliver certain aspects has changed, having taken his findings into consideration. 
I hope that helps. I’ve had a look but can’t find the data / relevant stats. Good luck counterbalancing!

2
In reply to Osiris:

Whenever a safety procedure is a complicated as the one you have prescribed, it certainly has to be very highly practiced in a safe environment.

 connor 08 May 2020
In reply to Osiris:

In my mind,  under the scenario you mentioned a Y hang abseil would serve you better. Having your casualty close to hand and able to control them much better. Although I understand that in some situations a counterbalance may be the only option. It's pretty far down my list of solutions though. 

Counterbalance abseils are pretty spicy!  The only time I've really used them when I've had to have been retreating from big mountain objectives where no other anchors have been available. For instance over a large rib of loose rock that can't be slung or is too loose to take rock gear.

Just my two pence.

3
 Alex Riley 08 May 2020
In reply to connor:

I think you are talking about a different type of counterbalance (simul abseil). In this instance the op is using a counterbalance for the first stage of a multi pitch rescue because a y hang or pick up rescue wouldn’t allow further use of the rope.

Yes they can be spicy, but so can any of these rescues if you mess them up.

OP Osiris 08 May 2020
In reply to Will Nicholls:

That's interesting. I'd like to see some evidence for that, too. Surely the type of edge matters? Blunt vs sharp. Also, what about falling off an edge or even rope being directed over an edge during a fall - both are quite common and the force involved in a fall would surely be higher than a measly 1kn?

OP Osiris 08 May 2020
In reply to meggies:

Both really good.

 jezb1 08 May 2020
In reply to meggies:

> Check out the Leading Edge Mountain YouTube channel and the JB Mountain Skills YouTube channel.

> Sam is a MCI assessor and Jez is a MCI mentor, so loads of great stuff between them.

Thanks for the mention!

 danm 09 May 2020
In reply to Osiris:

Video explanation here:  youtube.com/watch?v=IL2r_f2g4Sw&

 Suncream 09 May 2020
In reply to Will Nicholls:

I don't understand this. In a normal lowering situation, the tension in a single rope is the weight of the one climber. In a counterbalance abseil, the tension in each end of the rope is the weight of one climber. In a y hang abseil on two ropes, the tension in each strand is half the weight of two climbers. It's all the same? The lowering situation is worse since the rope is running, but that's by far the most common, in sport climbing etc.

Admittedly the tension is double that found in a standard abseil on two ropes.

Post edited at 09:59
 Alex Riley 09 May 2020
In reply to Suncream:

In a sport lowering context and counterbalance  the weight on the top anchor is 2x the weight of the climber(s) 
 

With bolted anchors the rope is less likely to directly running over the rock, whereas with trad protection the anchors are naturally closer to the rock (generally) and so are more likely to run over the rock. That’s my opinion and isn’t necessarily always the case.

Post edited at 10:13
 Suncream 09 May 2020
In reply to Alex Riley:

That's all true but not the point I was making. Force at the anchor is double the force in the rope as there are two strands coming down from it, one to the climber and one to the belayer. The force in each strand is what matters for whether the rope is cut, and that's the weight of just the climber.

In reply to Osiris:

When I was practising for my summer test, I spent a lot of wet afternoons practising loads of different situations in the climbing wall. 

The wall has the advantage that it is steep, but short. Meaning you can get the other person to properly weight the rope. All these improvised rescue situations get way harder/more realistic on steep ground. You can also get way more done in an afternoon at the wall, than you can in a day at the crag.

Walls are also bolted, meaning you always have quick bomber anchors. 

Once you have mastered all the things, in a controlled environment, head outside to try them for real. Backing everything up is really important, and put in a few more pieces to the belay, especially if you're going to haul on it. Fat ropes single ropes are way easier to handle, and way less likely to get trashed than skinny singles. 

Good places to practice these things in North Wales are: Vector Buttress, Carreg Altrem, The Grochan, and Castell Helen. Basically anywhere vertical, with good belays. 

However, if you are not preparing for a MCI assessment or BMG Summer test, I wouldn't stress about things like counter balance abseils. I'd just go climbing and enjoy it - that chances of having to do any of these things in remote.

However, It is worth learning how to escape for a loaded belay, and prussik up a rope.

1
OP Osiris 09 May 2020
In reply to danm:

Ok interesting, so one person abseiling is totally fine, but two people cuts the rope. I see value in that video, but it's hardly a realistic experiment. I wouldn't abseil over a 'sharp' edge (or I'd try not to), so the rope wouldn't be under tension over such a small area. Plus, the device they use to test it looks pretty sharp and it rotates. Surely quite different to a static rounded edge of rough granite. However, it has made me think..

 Will Nicholls 09 May 2020
In reply to Osiris:

It was really interesting... the type of edge didn’t seem to matter that much as I remember. He gave an example of recreating a fall where as a leader you may traverse across, go round an arete, and then climb up. He basically said that’s potentially really gnarly, he used to do that kind of thing without thinking, but now wouldn’t climb that kind of pitch. He’s a guide as well and climbs in the 8s, it was pretty fascinating as a result.

One of the accidents that he’d heard of inspired him to investigate edges and weight on ropes. A Swiss guide’s rope had cut over an edge as he lowered them at the same (both on one rope) over an edge, with sadly tragic consequences.

In his findings, it wasn’t a case of the rope snapping due to load, but over an edge. As an example, he found it’s probably okay to lower two people on one rope down a snow slope / icy couloir, as they’re shouldn’t be any edges. However, as soon as there’s an edge involved and more than 100kg on the end then the chance of the rope cutting is massively increased. 
In essence, his findings were pretty alarming to me. I’ve changed the way I work and climb to be much more mindful and guarded against such situations. I’ll try and find the slides. 
A bit of a waffley reply I’m afraid - I just can’t remember the stats well enough! Cheers. 

 Will Nicholls 09 May 2020
OP Osiris 09 May 2020
In reply to Will Nicholls:

Here's a (great?) example of your first paragraph vimeo.com/210809039

 nz Cragrat 21 May 2020
In reply to Osiris:

Pretty scary that, found myself crunching up a bit waiting to hit the ground

 doz 21 May 2020
In reply to Will Nicholls:

Thanks for that... definitely food for thought

Has always slightly unnerved me the number of times I have observed alpine guides lowering bundles of clients, often wearing skiis.... ready-made sharp edge!


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