Self rescue hauling


Original Post
David Coley · · UK · Joined Oct 2013 · Points: 70

Hauling – the theory

Most climbing manuals have a section on hauling for self-rescue and show a series of standard methods. Having tried many of them out I have to question if some authors have really used the systems they describe, and if they have, I would question if they have tried them with various combinations of rope, prusik diameter and casualty weight, or from various realistic stance positions. (Some online videos have the person doing the hauling walking 10ft backwards as they haul – in most real situations there won’t be this much space.) I’m not trying to be critical, but I can’t get them to work except in ideal circumstances. Maybe I’m just weak. Although many texts do indeed stress the difficulty of hauling, there is a difference between suggesting it is will be difficult, and that it simply won’t work as described in the text.

Being able to haul is important. A likely scenario is the need to haul a climber who is hanging in free space, and is too injured to prusik, up to a ledge so they can remove their weight from the harness before they get harness hanging syndrome. Even if you can escape the system and go for help relatively easily, it will be many hours before the helicopter arrives, so the casualty needs to be got to a ledge and parked.

In the following I present my analysis of the situation and try to provide a solution. I would really like to know if anyone else has tried to use the final solution as a self-rescue hauling system, and why it isnÂ’t in the standard texts, as it is the only solution I can get to work. I assume others have played with it and there must be something fundamentally wrong with it.

1. Rope diameter
One question is what is the best diameter of cord or sling to run through the carabiners that are acting as pulleys? Should we use the climbing rope, or should we replace the rope with a thinner cord? The experimental data below is from Jim Titt. It clearly shows that friction at the carabiner is likely to be considerable, and that we should use thin cord or dyneema webbing not the main rope. This clearly shows that by running the main (fat) rope over a couple of carabiners most of the mechanical advantage will be lost: so, think thin.

from multipitchclimbing.com

2. Hand strength

www.multipitchclimbing.com

You can get some idea of what you can lift by looking at the forces involved. Left, with pulleys (assumed to be 100% efficient); right, with carabiners (assumed to 50% efficient). The assumption here being that 25kg might be the maximum lift a light climber can apply repeatedly through gripping the rope with one hand.
user.xmission.com/~tmoyer/t...
reports a mean grip strength of 209N, i.e. 21kg, on the brake hand when belaying, so 25kg isnÂ’t an underestimate). The hauler will no doubt use both hands, so we might expect them being able to apply twice the force and raise 88kg (194 lb). So they might just about be able to lift a climber a short distance before exhaustion sets in.

3. Friction at the edge
The situation will be worse if there is friction over the edge, adding another 50% reduction in efficiency (or more) and indicating it might only be possible to raise 22kg with the 25kg per of lift. I.e. your wonderful 3:1 system isnÂ’t in reality even a 1:1 and the maximum weight of climber that can be raised is 44kg (97 lb). In his book, FasuloÂ’s recounts the story of a team of four trapped on Bugaboo Spire in Canada. Despite having three people to haul, they fail to raise the fourth member of the team! The most likely reason being friction over the edge in front of the stance. This is not surprising. If the casualty (with clothing, climbing equipment and sack) weighed 100kg then because of edge friction one might need to apply an equivalent of 200kg of lift above the edge, which given the analysis of the 3:1 without pulleys shown above still means over 100kg equivalent on the pull end of the rope. i.e. it would be the same as hauling someone free hanging where there wasnÂ’t an edge straight up the rope.

4. Will a 9:1 work?
A 3:1 can be converted into a 5:1, 7:1 or even a 9:1. The problem with all these more complex systems is that the stroke length (the distance your hand travels) will be very small with realistic belays. In a professional rescue from the top of the crag (or a crevasse rescue) the anchors will be placed a long way back from the (padded) edge leaving plenty of space to walk around and to place the prusiks/pulleys a long way from each other. This means the stroke length will be considerable. If you are pulling 3m (9ft) of rope through such a system on each stroke, the casualty will be rising 30cm (1 ft) with each stoke on a 9:1. This will give a reasonable rate of progress. In a realistic rock climbing self-rescue situation you are unlikely to have this space. You will be on a small ledge with the anchors at chest height (and the powerpoint even lower) and your stroke length at maximum power might be 30cm before your hand is too high to pull hard, or the prusiks/pulleys come into contact with one another. A 30cm stoke on a 9:1 means the casualty will be lifted 3cm. But the system might well have 2cm of slip-back, so they will have gained only 1cm. If you can only manage 20cm of stroke, you will get nowhere.

A hauling system that actually works?

Having stressed the difficulty of hauling and done some analysis to show where some of the problems lie, what does work with an incapacitated casualty when you donÂ’t have a microtraxion and a pulley?

To work in practice I would suggest the system needs to:
1. Use the body weight of the hauler or she will simply run out of strength. This means pulling down, not up.
2. Not use the fingers to drive the system as they are weak, particular so when gripping a rope. This means the attachment point should not be the hands.
3. Minimise friction at the carabiners by using a prusik cord or thin dyneema sling rather than the rope to lift the casualty.
4. Use a clutch that works reliably with little back-feed and doesnÂ’t add extra friction.
5. Will work effectively once the person hauling has moved the hauling point over the edge to remove the friction generated by the edge of the stance. This means it might have to work from a hanging or near-hanging belay.

An obvious starting point is to ask what those dragging haul bags up big walls use, and see if any of their systems can be adapted to meet the five criteria given above and without the pulleys and rope grabs big wall climbers use. One that I think might is the 2:1 big wall hauling ratchet.

The key element of this system is that the load does not pass through the clutch during the lifting part of the cycle. This means that one can use just about anything as the clutch even if it would introduce far too much friction to be used within a normal system. This means you can use your Reverso. This means no messing around with French prusiks that donÂ’t grip when you need them too, or that wrap themselves around their carabiner. This means you will have a very reliable and safe clutch. The Reverso might even already be in place.

Luckily, the 2:1 system also uses a thin pull cord, is designed for pulling downward, the attachment point is not the hands and it works from a hanging stance. So it ticks all five criteria. Bingo. It is also field-tested most days on El Cap.

The system used by big wall climbers makes use of pulleys and a rope grab, so some adaptation is required – see the following photo. I have tested the system and it works well in realistic scenarios. It still takes a long time to raise someone 50m, but it isn’t exhausting and use of the Reverso as the grab makes it feel secure.

from multipitchclimbing.com

The Adapted 2:1 Hauling Ratchet. If you don’t have a Reverso to hand, use a Grigri or a Garda hitch (and the occasional backup knot). The pull cord (a long single strand of prusik cord, a length of cordelette, or a thin dyneema sling) has been tied off to the upper carabiner with an alpine butterfly so the knot can be removed later. The key to making the system efficient is to set the pull cord to just the right length. Hence it is attached to the belay loop of the harness using a clove hitch around two carabiners so you can adjust it even after it has been loaded a few times. To lift the causality simply sit down hard or walk backwards. When the two “pulley” carabiners meet at the end of the pull stroke, pull the rope through the Reverso, then stand back up and slide the prusik knot back down the rope. The person hauling needs to be clipped to the anchors via a tether or via the rope in case the pull cord snaps.

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

Dont forget that with a dynamic rope you are fighting rope stretch with every pull

And the rope is getting sawed on the edge every time that you pull the climber up a few inches (which is all youll get in a realistic scenario with someone heavier than you)

Not to mention the friction in a real life scenario with the gear still in the climb

For those who want to practice "realistic" hauling of the second

- lead up some a long wandering route to a semi hanging belay (like there are on alot of multis)

- leave the gear in (like you would on a multi pitch)

- make sure the second has all the normal gear they would carry on a long multi

- make sure the second is at least equivalent if not more weight than you (realistically your partners will be of all different weights, not just a 180 lb guy hauling a 100 lb girl)

- they are incapacitated, not moving at all

- only use what gear you would have at the top of a hard long pitch (when was the last time you carried a good quality pulley on a hard free lead or ended up with tons of lockers and cord at the belay)

- try hauling em up

Most folks simply cant

Note that professional rescue teams need pulleys, static ropes and multipleteam members to haul someone up

Hauling someone is really only useful if they cant make a few moves or have a minor injury and need an assist getting up

Many folks have unrealistic assumptions on being able to haul a partner up a climb ... A day spent practicing hauling under the realistic conditions above quickly disabuses em of that notion

Also note that hauling an injured party, especially if they are immobile, can make their injury worse ....

The above system looks interesting ... But hauling a bag is different fron trying to haul a 200 lb guy on a wandering pitch with the gear still in on a dynamic stretchy rope

Em Cos · · Boulder, CO · Joined Apr 2010 · Points: 5

If the gear is still in and your partner is completely incapacitated, you won't be able to haul them up anyway.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 525

I agree with the previous two posters that, practically speaking, hauling is very rarely a viable option. It just plain isn't going to work most of the time, and anyone who has actually experimented in realistic circumstances knows this. And David's excellent analysis did not include the cumulative effects of carabiner friction, which kills off a good deal of the mechanical advantage anyway, and this before before one tries hauling through the often-recommended clutches (eg Reverso in guide mode, Garda hitch) which will add even more friction and often bind enough to further reduce the theoretical mechanical advantage. To see this binding effect in action, have a look at this instructional

https://www.youtube.com/watch?v=KaERKYT-fK4

in which a Reverso in guide mode is being used as a clutch. Each time the climber hauls (for example around 2:01), you can see the clutch strand go slack, which instantly reduces the theoretical mechanical advantage from 3:1 to 2:1 before one factors in any of the friction effects.

It is amazing to me that the "self-rescue industry" has consistently ignored the experience of big-wall climbers, the one set of people who actually haul loads regularly, and just keeps putting forward outdated techniques of almost no use to climbers who have to improvise a rescue.

I haven't tried the improvised 2:1 system David describes in a practice self-rescue hauling situation so can't offer anything like informed feedback. But ignorance has never stopped internet posters from offering unsubstantiated opinions, so I feel part of a long tradition in saying that if anything is going to work, David's proposal has by far the best chance.

Perhaps it is also worth mentioning that in the big wall context, the now-standard 2:1 system seems to have first been described by Chongo; see chongonation.com/books/bigw... . The method was popularized by Pete Zabrok's internet posts and his tech tips article in climbing magazine, climbing.com/skill/tech-tip... (this link does not work as I'm posting this).

berl · · Seattle · Joined Apr 2008 · Points: 25

The first (straw man) system in the OP (and the video) are both actually 2:1, right? you pull 2' of rope and it raises the climber 1'.

David Coley · · UK · Joined Oct 2013 · Points: 70
berl wrote:The first (straw man) system in the OP (and the video) are both actually 2:1, right? you pull 2' of rope and it raises the climber 1'.
The one in the OP is for sure. And that makes it interesting as the one with lowest theoretical advantage is the one only that worked in the field test.
David Coley · · UK · Joined Oct 2013 · Points: 70

Just to reinforce what I said in my original post: I have tried this in a realistic situation. And I used a person, not a bag. I hauled them 30m up a cliff. I weigh 60kg, at a guess they weighed 80kg. I did it off a hanging belay (by moving the haul point over the edge first). They ascended 6inches per stoke.

I had previously tied many of the other systems given in the books. They were all worthless.

David Coley · · UK · Joined Oct 2013 · Points: 70
berl wrote:The first (straw man) system in the OP (and the video) are both actually 2:1, right? you pull 2' of rope and it raises the climber 1'.
I've just watched the video. It is a 3:1 in theory. But as rgold points out, one stand becomes unloaded as she pulls, so it it only in truth a 2:1.

I don't know the person in the video. But I don't think there is 80kg of climber hanging under a roof as she describes.

To me the interesting thing is whether she has ever tried to do what she demonstrates. I'm guessing not. For one the rope is going over an edge in the distance a ridiculous angle. This very much gives the wrong impression about when the technique she is using will work. It won't work with a hanging climber and a bad edge (like the one she has).
berl · · Seattle · Joined Apr 2008 · Points: 25
David Coley wrote: I've just watched the video. It is a 3:1 in theory.
I disagree- it's identical to the first pic in the thread, just with a reverso at the highpoint. She would have to redirect again at the top and pull down (in this case) if she wanted a 3:1.
Jeff Scheuerell · · Unknown Hometown · Joined Jan 2007 · Points: 1,555

Sorry berl, you are wrong, not the same. Z pulley system/3:1 minus a lot of friction.

Marty C · · Unknown Hometown · Joined Aug 2008 · Points: 70

David,

FYI - I have attached a page from the Ontario Rock Climbing Assoc. Safety Manaul (1990)which shows an approach that mirrors your experience:
- use thinner cord
- isolate(remove)Reverso from system to minimize friction/sticking

One difference is that their system (which appears to be a variation of the Spanish Burton pulley system) has a theoretical mechanical advantage of 3:1 which is higher than your 2:1

Like the others who have posted, I agree trying to haul a 2nd. can be near impossible with all the gear/edge/other friction concerns.

Pulley system

berl · · Seattle · Joined Apr 2008 · Points: 25
Jeff Scheuerell wrote:Sorry berl, you are wrong, not the same. Z pulley system/3:1 minus a lot of friction.
Thanks- you're totally right about the movie, but it's the same as the first setup in the thread, right? (the one with the rope only).
David Coley · · UK · Joined Oct 2013 · Points: 70
Marty C wrote:David, FYI - I have attached a page from the Ontario Rock Climbing Assoc. Safety Manaul (1990)which shows an approach that mirrors your experience: - use thinner cord - isolate(remove)Reverso from system to minimize friction/sticking One difference is that their system (which appears to be a variation of the Spanish Burton pulley system) has a theoretical mechanical advantage of 3:1 which is higher than your 2:1 Like the others who have posted, I agree trying to haul a 2nd. can be near impossible with all the gear/edge/other friction concerns.
Thanks for image. I'll give it a try and report back. The stroke length might be the issue.

On the question of hauling being impossible. I now think it isn't (in part because I just hauled someone up a cliff from a hanging stance). It is just you have to know the impact of each variable and how to solve the issues.
Marty C · · Unknown Hometown · Joined Aug 2008 · Points: 70

David,

Obviously, the diagram is "not to scale"

Re: throw length - it can be adjusted to make it longer
On a ledge, with the pull cord attached to your harness to allow body weight to provide the force, how much length would be useable/practical?

When you did your "experiments" were you hauling a 2nd with numerous pieces of pro (and potential bends in the rope) between you and the 2nd or in a "top rope" scenario with a free running rope between you and the 2nd?

Thanks.

Paul Ott · · oakland, CA · Joined Jun 2014 · Points: 5

I like this discussion alot. These are the kind of people I like to climb with. Practicing the systems in real life makes a safer climber and climbing partner. Thank you for the extremely captivating conversation!

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 525

David, the diagrams you posted appear to have been created for another purpose, namely to demonstrate the best place to put a single pulley if that's all you have. If you have two pulleys assumed 100% efficient, then your 25 kg pull gets you 75kg of lift since the system is genuinely 3:1. But if carabiners are used at both pulley points and their efficiency with ordinary climbing rope is, as you say, 50%, then you only get 43.75 kg for your 25 kg pull. Put another way, the practical efficiency of the so-called 3:1 system is only 1.75:1. Add edge friction to that and the chances are good that there will be no mechanical advantage at all, a fact that anyone who experiments with such systems has found out.

Jim Titt's numbers suggest that with 5mm cord, carabiners are 69% efficient. If this is true, then the 2:1 system rigged with carabiners would have an unimpressive practical efficiency of about 1.2:1. If that system works better than the ordinary 3:1, I suspect it does so for two reasons.

(1) Because of the use of the belayer body weight. Pulling with both hands, i.e. with 50 kg, on the 1.75:1 system gives you 87.5 kg of lifting power (with no other sources of friction present), whereas pulling with 80 kg bodyweight on the 1.2:1 system gives you 96 kg of pulling power. And since the hands will inevitably tire, the pulling power for the 1.75:1 method will decline during the raising operation, perhaps enough that belayer fatigue will make it impossible to complete the task.

(2) Because of the elimination of edge friction. Body weight hauling can be done from a hanging stance, eliminating the hauling line bending over the lip of the belay ledge.

Given the apparently very modest mechanical advantage of the 2:1 system rigged with carabiners, my guess is items (1) and (2) are pretty important. So problems might still ensue if, say, the belayer is much lighter than the second being raised, and if either edge friction can't be eliminated, say because of significant bending points at a distance from the belay stance, or some other source of system friction, most notably the rope running through protection points, is still present.

As for the Chisnall system, still assuming 71% carabiner efficiency, you get a mechanical advantage of about 1.9:1, of course at the expense of a a 33% reduction in stroke length.

David Coley · · UK · Joined Oct 2013 · Points: 70
rgold wrote:David, the diagrams you posted appear to have been created for another purpose, namely to demonstrate the best place to put a single pulley if that's all you have.
Well spotted! I inserted the wrong diagram. Here is the right one!

www.multipitchclimbing.com
David Coley · · UK · Joined Oct 2013 · Points: 70

To rgold. Yes I agree most of the 2:1 is lost, but am I right that without it, we would just have a 1:1 around a carabiner (so one can pull down) which because of carabiner friction ends up as 0.7:1 making it impossible to raise anyone.

So the point of the 2:1 is really just to create a counterweight haul that isn't killed by carabiner friction.

I will try the more complex one as soon as I can.

Re friction from runners, These will need to be removed anyhow of as the casualty can't remove them and can't be dragged through them.

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

In real life you would need to rap down to remove the runners then re-ascend the rope ... Which means the pitch needs to be half the rope length or less unless you want to prussik down AND up the line, or the leader needs to be tagging a line (not guaranteed as many MPers have indicated they get the second to pack the tag line)

Nor would this be possible if theres any chance of even a mild swing on a traverse, you need the directionals ... One of the hauling scenarios is to haul someone off a traverse fall onto a blank face, you find out very quickly that its much easier if they ascend the rope

A person can have his legs incapacitated yet still remove gear

But realistically if a person is that screwed up you are going down not up

Youre going to get em down to a ledge and press the big red button

Or if no one is around, you still need to get em down as you wont be able to carry them by yourself down the descent and not get them even more hurt

Where hauling is useful is for short stretches at the crux, or where the injury is fairly minor and te climber can still move somewhat ...

IMO hauling shouls be practiced for those scenarios ... And for discouraging folks from thinking they can realistically haul folks up by themselves on your normal wandering multi route which often includes traverses

Remeber that if you partner gets injured its absolutely important that you keep yourself in good shape and from getting too beat up unless its absolutely needed

The injured party will be consuming most of the water and calories if they can and wearing most of the insulation, shelter ...

You need to keep youself in sound mind and body to help the rescuers

Jim Titt · · Germany · Joined Nov 2009 · Points: 490

After David asked for the efficiency tests I played with most of the usual systems and a few ideas. The practical killer for nearly all of them is the progress capture as as you increase the power ratio the stretch and give in the system gets worse and worse. In the end you lift a few inches and then whatever you use to hold the load gives a little and the hauling system gives a lot so basically you end up more or less where you started having expended an enormous amount of energy.
Ascending a rope alone is shattering enough so multiplying it by 5 times is going to be death for most climbers.
If you absolutely have to haul then logically the best solution is to descend to the casualty and far-end haul as you can tend the load, remove the protection and there´s no extra friction in the haul.

Will all respect to the charming lady and the School of International
Expedition Training the 3.1 tests out as a 1.35:1 and pulling from a much better position (directly over the strain guage bolted to the floor) I´m not strong enough to actually rescue my 95kg self. I managed 68kg briefly with both hands on a 10mm rope and 50kg would be achievable over a reasonably short period, there again I bend metal all day!

Cut the rope is an alternative.

rging · · Salt Lake City, Ut · Joined Jul 2011 · Points: 210

A couple of simple ways to reduce friction with what you would realistically have with you is a double length, thin as they make, dyneema sling. The other is one of those DMM revolver biners with the roller in it. Other than reducing friction, not loosing any gained progress from a good progress capture device like a tibloc instead of a prusic would be good.

Guideline #1: Don't be a jerk.

Post a Reply

Log In to Reply