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Looking for feedback on self rescue 'how-to' videos

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

Josh, I find the instructions clear, but still, think as bearbreeder has emphasized, that people who might actually try to use such systems should realize how ineffective they can be in real situations. I think it is worthwile to know how to set up such systems, with the knowledge that there is a chance that they won't work at all and if they do, they will only be practical for very short hauls. As such, hauling is an absolute last resort if it is even an option at all, and should never be used when the person to be hauled is able to prussik or significantly assist in the rescue process.

If we make what seems to be the standard assumption for the efficiency of carabiners (1/3 of pulling load lost to friction around each biner), then the best you can expect from a 3:1 is about 2:1 and the best you can expect from the 6:1 rigged as you showed is 3.5:1, going down to 2.3:1 if you redirect as shown. These numbers are before we add in the significant rope friction over edges and through protection points. There is a real possibility of eating up all the mechanical advantage.

Moreover, you're losing a huge amount of mechanical advantage by using a Reverso in guide mode as a progress capture device. (I suspect the same is true for systems that use an alpine clutch.) Every time the climber hauls in all of your videos, the load strand goes slack because of the Reverso friction (this is a very prominent feature of the opening still of the latest video), meaning you've only got a 2.7:1 ratio with purported 6:1 rigging.

Considering the friction problems that can't be avoided, adding in a major additional source by using the Reverso seems to me to be a bad idea. Using the Reverso is, of course, much easier than the alternative of getting it out of the system, but considering how ineffective improvised hauling can be in the best of circumstances, further crippling the process with a lot of extra friction seems particularly unfortunate.

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

Talking about long hauls in real situations. Has anyone ever done a bottom end haul like one might do when soloing a big wall. i.e. drop down to the casualty and haul from nearer them. Thereby removing the friction from the edge of the ledge near the belay. Being one would have to prusik down to them to unclip any pieces anyhow this seems sensible.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

I've never tried it practicing (and I've never had to haul someone in real life). Perhaps the main issue is that on a wall you'll be using a progress capture pulley and jumars on the rope, and in the self-rescue scenario you're improvising with carabiners and prussik knots. Walls are usually steep and anchors are situated so the hauling strands don't bend over the lips of ledges, but this can't be assumed for improvised self-rescue. In the situation depicted in Josh's latest video, you'd have not only the load strand but now also the hauling strand bending over the edge of the ledge. This could require 40% more force on the hauling strand than would be required of someone on the ledge.

So, the potential for far more friction, the difficulties imposed by non-automatic progress capture, and the elimination of even the small mechanical advantage available on the ledge will make a bottom haul considerably more problematic then it is with wall gear. Still, in the right conditions, with little enough friction and perhaps a weight mismatch in the favor of the hauler, it just might work.

Just to be clear, I don't think there's anything the matter with learning hauling technique---the more tricks you have up your sleeve the better---but I do think what would serve most climbers far better for the kind of emergencies that can actually be handled by a single person is to know all the tricks involved in retreating with an injured partner.

Josh Beckner · · Unknown Hometown · Joined Feb 2011 · Points: 15

Thanks for the thoughts. Very well put. Rgold, your points are make a lot of sense. There are indeed many times when this system won't work and having the reverso in the system will certainly make it worse. I have an 'escaping the reverso' vid but it need heavy editing or a retake before I want to put it out there. Once I do, I'll explain how it's more efficient to haul without the reverso in there.

In the near future I'd like to make a video that covers all the pros and cons of each haul system, as well as limitations.

For now, I just want my students to know how to rig this so they can employ the best system in the scenarios that we drill them on, usually on glacier/crevasse rescue.

Any one else? Thoughts? Are the concepts clear?

jktinst · · Unknown Hometown · Joined Apr 2012 · Points: 55

OK I'll stop going on about the 9:1 but my comments about the effective pulling distances of hauling systems are just as applicable to choosing among other higher mechanical advantage systems.

You indicate that the main application of the 6:1 is for glacier travel and crevasse rescue but the set-up used to illustrate the technique is obviously that of a leader having to haul the second from the top of a rock climb. The limitations that make the 6:1 only marginally suitable for many rock climbing self-rescue situations are less prevalent in crevasse rescue situations where you can typically set the primary pulley anchor fairly far back from the lip of the crevasse.

The rock climbing set-up shown here is also somewhat atypical for the top of a rock climb and even more atypical for a mid-route belay. In real life, the lone rescuer of an injured partner will seldom enjoy the luxury of having what looks in the video like about 4 m between where he has (or where he could) set up his belay/hauling anchor and the lip of the ledge, which is often going to be the lowest point along the rope where the primary haul prusik can be set.

My tests indicate that by adding the 2:1 to the 3:1 to get the 6:1, you cut the maximum raising possible in a single pulling sequence to about 26% of the 3:1's maximum raise. The 5:1 modification of the 3:1 only cuts it back to about 46%. The height lost to prusik stretch when using even a short prusik for progress capture is about .2 m for each reset. I haven't estimated the equivalent number when using a reverso/ATC guide but knowing (and seeing on the video) how you have to have the load strand somewhat slack to be able to tighten the brake strand, I would guess that the number in that situation is probably not much lower.

If the maximum pull distance of the initial 3:1 is, say, 1.5 m due to the inherent limitations of the belay position, the 6:1 will force you to stop raising and to reset the system after only about 0.4 m of raising, of which you will lose 0.2 m to settling on the progress capture prusik while resetting the system, which gives you only 0.2 m of effective raising per sequence! By comparison, the 5:1 conversion of the same 3:1 will stop after about 0.7 m of raising which gives 0.5 m of effective raising per sequence, ie, more than double the raising efficiency of the 6:1!

The 5:1 has 83% of the theoretical mech. adv. of the 6:1 but when you work out the practical mech. adv. based solely on the known pulley efficiencies of biners (ie not taking rope and prusik stretch into account), the mech.adv. of the 5:1 is more around 90% that of the 6:1. If you include the other efficiency losses in these systems (eg prusik stretch), the difference would be even less because the 5:1 uses one less prusik than the 6:1. And, of course, there's the extra time needed to loosen and move the additional prusik (or clove, as in the video) of the 6:1.

To sum up: in terms of mechanical advantage and effort needed, the 6:1 is essentially no better than the 5:1 but in terms of raising efficiency (ie, time needed to complete the raise), the 5:1 is a lot better, with at least (46/26=) 1.8 times better raising efficiency (and much more than 1.8 times in situations where one is limited in how far away from the anchor the primary haul prusik can be set).

Based on this, I would say that if one finds himself in need of greater mech. adv., be it in rock climbing or crevasse rescue situations, but does not want to go straight to the 9:1, the first thing to try should be the 5:1. If that is still not enough to effect the raise, there would simply be no point in trying out the 6:1 instead. The options at that point would be either to forget about hauling or to switch to the 9:1 (oops, sorry, here I go again).

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

IMO the first thing anyone should do when practicing hauling for self rescue ...

is to try to haul up someone heavier than them without pulleys on a dynamic rope with some of the gear still in on a real lower angle climb to realize how totally and utterly slow and possibly futile it is

when i talk to folks about basic self rescue, some of them say "ill just set up a z pull and haul em to the top if theyre incapacitated" ... you can really tell at that point who practices their skills realistically and who doesnt

i think one should know the 3/5:1s as they are most useful for folks who cant quite make a certain move, or might be slightly injured (broken finger, banged up shoulder) but can still climb in general

no matter who you are, in a realistic free climbing multi scenario, you arent hauling your incapacitated partner up to the summit ... theres a reason why rescue teams need several people, and all this fancy gear to haul someone up safely

;)

Guideline #1: Don't be a jerk.

General Climbing
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