Mountain Project Logo

Self rescue hauling


Jim Titt · · Germany · Joined Nov 2009 · Points: 490
rgold wrote: The huge range of apparent carabiner efficiencies (53% to 76%) and the inconsistency of individual experience suggests that either the same things aren’t being tested in comparable ways, or that the weight estimates are not accurate, or that these systems are very sensitive to rope and carabiner type; probably at least two of these effects are present. Sadly, this means that the success of the system may be questionable for you even if someone else has managed to use it in similar conditions.
The range of variation in karabiner efficiency is worse than you think! The numbers I gave David are to show the relative efficiencies of different materials dynamically tested with the same weight. If you start varying the weight and the pull force and the numbers go haywire.
18%, 45%, 65%, 72% and 100% are all measured static efficiencies of Davids 2:1 hauler with the same lifted weight and different hauling forces and there will be another load of varying numbers for the dynamic efficiency as well.
The karabiner efficiency is load dependent which i´ve seen in other applications as well.

What this means is each part of the system has to be looked at individually as the efficiency over the first karabiner is nothing like that of the second.
Using a 30kg test weight and 5mm cord I get 53% for the first karabiner and 36% for the second one in a 2:1. This would probably give dynamic efficiencies of 79% and 54% but that´s very rough estimate and assumes the hauler can get into the dynamic mode anyway.
Dynamically testing this isn´t easy somehow (same with human-sized weights) but I might give it a go sometime.

For different weights/loads there´s no reason to suppose this will change which makes a theoretical model a bit difficult, adding to the problem of considerable variation in makes and types of cord.
David Coley · · UK · Joined Oct 2013 · Points: 70

Thanks everyone for sticking with this post.

The system in the video is the 2:1 I showed at the start of the post.

Looks like I need to shoot a longer video and with the casualty either hanging in free space or being scrapped up the wall.

I will try and use 7mm nylon as a worst case.

I will do it with and without pulling up on the rope.

The long cord, walking down the wall thing was just to show that it was a gentle process compared to the battle of using a normal 3:1

The following video shows the original system in action on el cap. Note the hauler is using pulleys. The minitrax does not add any efficiency over a Reverso as it carries no load during the stroke. One thing to note is that he is making short strokes. And bouncing. And working hard.

I'll be soloing on El Cap next month, so should be able to return with more of a gut feel for the approach.

youtube.com/watch?v=B74MEcI…

Thanks again.

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

Here's wishing you a great trip up El Cap, where your hauling rig will have pulleys and so won't be subject to most of the obstacles to success that are part of the improvised set-ups.

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

Here are the test results mentioned earlier plus other reflections. There's a lot, I know. Sorry. This coincided with my recovery from knee surgery and you can tell I had some spare time and nowhere else to be, but, believe it or not, I did try to keep it to the point.

BACKYARD TESTS

In the "backyard tests", carried out in 4 sessions of about 3 hours each, the anchor was about 10 or 11m up in the tree. The load was my picnic table loaded with varying amounts of liquids, heavy tools and exercise weights. As I mentioned earlier, with my gear on, I weighed about 70kg. I started with a test weight of 70kg, then moved up to 90 and 110kg. The hauling systems I actually tested are highlighted in bold in the table. The other systems shown are, for the most part, a selection of systems often found in climbing self-rescue material. Of course, this is, by no means, an exhaustive list of the systems that could be used in self-rescue situations.

The subjective assessment of each system and weight combination tested rates the overall effort needed. The main components of the effort were ascending the rope or pull cord, with or without a pull-up action. The ascending effort remained about constant per movement but, of course, some systems required a lot more movements than others for a given height gain. The pull-up action ranged from an easy, long (about 1m) one-handed pull to a very hard and short (30cm) two-handed pull.

"Easy hauling" (E) meant that I could gain about 7m of elevation in anywhere from a few to about 7-8 minutes and with the kind of light effort that could clearly be sustained over significantly longer height gains (this typically meant relatively few ascension movements per raising sequence and, when pulling up, longer, easier pulls). "Moderately difficult hauls" (M) typically took longer for the same raise, ie, require somewhat more ascension movements and/or somewhat harder pulls. These would typically result in appreciably more fatigue than the easy ones but could still be sustained over longer times & height gains. "Difficult hauls" represented another increase in effort and were typically stopped after about 5m when it was clear that going on to somewhat greater height gains would be feasible but that longer hauls than about 15m would either take a very long time or quickly become exhausting. The "Hard haul" (H) rating was applied only to systems requiring pulling up where that effort was pretty much at the limit of the feasible (the two-handed 30cm raise mentioned above). These hauls were concluded after much shorter height gains (about 2-3m). Raising a few more metres with these (probably up to 5-6m total) would be feasible but any more than that would clearly be unrealistic for me. And of course, there were more than a few "Impossible hauls" (I) where the system used and my own weight and strength were simply insufficient to achieve any raise.

Other abbreviations: CB=counterbalanced; MA=mechanical advantage.

CALCULATIONS VS. SUBJECTIVE EXPERIENCE

As has been said, there are too many variables to be able calculate the real haul capacity of a given system. I simply wanted to see if, keeping the same biners, rope and cord throughout, the calculations might provide a ranking of "weakest to strongest" of the different systems tested that would correlate reasonably well with the subjective rankings from the tests. This appears to be the case, at least for those systems that fall within the range of the weights tested. Systems providing MAs much in excess of that needed for the 110kg test could not be ranked with any accuracy. In any case, no-one should take the calculations and rankings reported here as hard currency, much less use them to decide what system(s) to deploy in an emergency without having tested them first. At most, the information given here may facilitate zeroing in on a few systems to test that should be more likely to work for the particular weight ratios of a climbing team. If your own testing shows that the selected system is either not strong or not fast enough, you can then move to testing systems slightly higher or lower in the strength scale with a reasonable expectation of fairly quickly finding the right system for you. For systems not considered here, you could also work out your own calculations and see where the systems fall along the scale before deciding if they'd be worth testing.

In the calculations, I usually used 25kg when pulling up in a pull-down system. Of course, this and the 70kg "rescuer" weight reflect my own situation, which, I hoped, would allow a better comparison with the subjective experience. Adapting the numbers to another situation is simply a matter of applying the ratios to the actual weight(s). However, if one's "weight-to-pull-up-strength" ratio is very different from the ones used here, new hauling capacity ratios would need to be calculated. The ratios shown are essentially calculated MAs for pull-up only and pull-down only systems but for pull-down systems with an added pull-up component, the "one" side of the ratio is always taken, in the calculation, to be the rescuer's 70kg, whereas the calculated number includes the added forces applied by pulling up at 25kg, which is why I called this "hauling ratio", as opposed to "MA".

Whenever a cord was needed, I used the same 7mm static nylon cord considered to have a 66% transmission efficiency for a single pass through an HMS anodized biner, regardless of its position in the system. If the biner was twice-looped or had other things clipped or attached to it that would be expected to decrease its transmission efficiency, the transmission efficiency was arbitrarily lowered to 60%. For climbing rope (10.3mm) on biner, I used David's 50% transmission value. For lightweight pulleys, regardless of rope/cord diameter, I used 80%. Any pulley point associated with a progress capture system was considered to lose an additional (and also arbitrary) 10% of its transmission efficiency to the unattended prusik, ATC guide in guide mode, Gri-gri, etc. However, no allowance was made in the calculations for efficiency losses due to prusik and rope stretch.

PULL-UP ONLY SYSTEMS FOR "LESS-THAN-BOMBPROOF" ANCHORS

The testing was concentrated on systems that make use of the rescuer’s own weight to effect the haul but I included some pull-up only systems in the diagrams and calculations. With a pull-down system (or a pull-up only system combined with a hanging belay), the resulting load on the main anchor is the weight of both climbers plus the resistance due to friction on the victim's side (plus, as rgold mentioned above, any spike in the load caused by "sitting down hard" or any other dynamic means of overcoming the load's inertia at the beginning of each pulling sequence). If there is any doubt as to the solidity of the anchor, it will, obviously, be best to avoid hauling altogether. However, there could be rare circumstances when a short haul, even on a somewhat dubious anchor, might be preferable to other alternatives. In this case, a haul system configured to pull up from a solid stance will be essential since the load on the anchor will only be the victim’s weight plus the friction MINUS the pulling up force. For the same reason, it will be essential to use a haul system with the lowest MA that can be realistically managed. Not only will this maximize the pulling-up force needed and minimize the load on the anchor but it will make the rescuer more sensitive to any increase in resistance that could signal an unwanted increase on the anchor load (which might be missed with a higher MA).

Doing a pull-up only haul without pulleys can be extremely difficult unless the victim is very light and/or can make a significant contribution to the effort, as shown by the calculations and experienced in past tests not reported here (and as often mentioned on this and other forums). With lightweight pulleys, it becomes feasible to consider hauling an incapacitated victim weighing the same or somewhat more than the rescuer. I used 35kg (instead of 25kg) for the force applied pulling up in the calculations. This is representative of what I could (barely) manage at my limit and for a very short haul only. Using a "pulling up only" system to raise an incapacitated victim requires a careful set-up. In addition to having a good stance (preferably a ledge just wide enough to be able to squat on for a more efficient pull-up effort), the rescuer may need a double-handled prusik to be able to pull hard on the rope or cord and a progress capture mechanism on the rope or cord at its most upstream point to allow several squatting pull-up movements (and resets of the double-handled prusik) for each overall haul stroke (see diagram II).

The main options for a pull-up only system off of a dubious anchor appear to be the Z 3:1 or, if the victim is heavier, the cord block tackle 4:1 (both with LW pulleys, of course).

Using LW pulleys
In the past and based on less systematic testing, I expressed that LW pulleys were an important part of a multipitch trad rack. However, the tests and calculations reported here indicate that they may not be as vital as I originally thought. They are essential for any pull-up only haul but this type of hauling should be extremely rare since, with a dubious anchor, self-rescue options not involving hauling would be much better. They are also indispensable to achieving really high MAs (possibly in response to high, unavoidable friction) but again, these should be very rare/unlikely situations. In more "regular" hauling situations (which are rare enough as it is in real life), it seems, based on these tests, that one could fairly well get by without pulleys, although, obviously, they make any haul much easier.

The pulleys I have are an SMC Mini and two Petzl Ultralegeres. The Mini is one of the rare prusik-minding LW pulleys on the market and in the past, I let that trick me into considering it mainly for the primary pulley point of classic systems where it could effectively mind the progress-capture prusik. This left me with two ULs which must be kept at hand at all times because the rope or cord can slip off them and which are, therefore, poorly suited for any low, moving and out-of-reach pulley point. For best efficiency, whatever pulleys are available should generally be placed at the most "upstream" pulley points of the system (closest to the rescuer). Seeing how I let myself get distracted from this rule by the SMC Mini, I felt that it was worth it to emphasize it again here (see systems IV, VI & VIII with the 3 different pulley configurations a, b & c, showing the advantage of using the swivel pulley - if only one is available - for low/moving pulley points).

5:1 & 6:1
In past threads, I've also attacked the usefulness of the 5:1 and 6:1 systems (as did David in his first post, as well) because they have poor effective pull distances (ie you have to stop pulling and reset the system long before the primary haul prusik comes anywhere near the primary anchor pulley point). This, combined with the lower ratio of height raised per length of rope pulled in one stroke means that their distance raised with each pull stroke and reset cycle is very low. The calculations shown here suggest a more nuanced position. I made these calculations assuming a pulley kit similar to what I have: one swivel pulley + 2 ULs. Since both the 5:1 & 6:1 systems have two low/moving pulley points, it meant that only one of them could get the swivel pulley while the other one had to remain with a biner. The 6:1 is one of those rare exceptions to the "more upstream" rule. A greater haul efficiency is obtained from having the swivel pulley in position 2 instead of 1. Still the capacity gain with respect to the 5:1 in its own optimal pulley configuration is fairly minimal and the 6:1 has one more prusik to manage.

Making effective use of the 5:1 or 6:1 requires being well-aware of their limitations and taking steps to counter them, such as making sure that the primary haul prusik can be reasonably easily set quite far from the anchor and that a long enough cord is available to go with that.

Finally, I discuss the 9:1 later on but should mention here that I don't think that it should be used in pull-up mode. If the weight of the victim and the unavoidable friction in the system are such that the 9:1 built with pulleys might be necessary, the strain would most likely be too much to consider placing on a dubious anchor.

ON-ROPE COUNTERBALANCED HAULING

I tested David's cord 2:1 in various guises as well as a few versions of more classic hauling systems but the bulk of my "tree tests" were on on-rope counterbalanced systems because the more systems of that kind I tested, the more I felt that this kind of hauling was well-worth a more thorough exploration. Of course any system where the rescuer uses his whole weight to pull down can be called a counterbalanced system but the "on-rope" variety have both the rescuer's and the victim's weight on the rope, on either side of the primary anchor pulley point biner (as in a counterbalanced rappel).

I don't know if there might be disadvantages to on-rope counterbalanced hauling that I missed (ie other than the ones I encountered and discuss below) but the more I looked into this during the testing, the more useful it seemed and the less I understood why it is not more often mentioned and considered as a valid option for hauling in climbing self-rescue (other than the simple fact that it is useless for crevasse rescue or for large organized rescues). One disadvantage is the need for the rescuer to prusik up the rope and/or the pull cord a fair amount. However, with regular hauling, the rescuer may first need to extend the anchor below the belay ledge to avoid edge friction, thus finding himself in a hanging belay and having to deal with prusiks and/or makeshift etriers. He will also probably need to start by removing the pros clipped on the victim's rope. He will then also need to use his own weight to effect the haul. All these factors together add up to not far off the same amount of effort as the prusiking done in on-rope CB hauling.

Another disadvantage is the fact that, with a biner-and-rope as the main anchor pulley point, you're stuck with approximately 50% transmission efficiency at that point. Of course, it is possible to substitute the biner for a pulley + progress capture mechanism but this disadvantage can also be seen as an advantage since, unless there is a huge difference in weight (2 times or more) between the victim and the rescuer, there will be no need for a progress capture mechanism. As a result, on-rope CB hauling keeps the rescuer's options open. He may use a CB rappel to reach the victim, cleaning the pros along the way and keeping an eye out for intermediate ledges with good anchor options. Once he reaches the victim, he will, of course, first perform a quick assessment and provide the most urgent first aid and, if required, initial relief from suspension trauma. After this, he can evaluate the situation somewhat more calmly and decide if the best course of action is really to haul or if it might not be to continue CB rappelling with the victim to the next belay/rappel station (or intermediate ledge) down, which remains an option thanks to the absence of a progress capture mechanism.

If hauling is the best option, the rescuer can also choose to effect the haul from just above the victim to keep a close eye on him and keep him from scraping too much along the rock, or to effect it from higher up to be able to run longer, more efficient hauling and resetting sequences (or use a combination of both approaches depending on the different circumstances encountered along the haul).

On-rope CB hauling from just above the victim is particularly useful when reaching an intermediate ledge with decent pro options. The rescuer can more easily raise and guide the victim to just above the ledge and gently begin depositing him on it by simply pulling down on his side of the rope (and raising himself in the process). He can then keep the victim still partially suspended (and secured) on the rope while he sets up the anchor and secures the victim and himself to it (the victim with a releasable hitch) before finishing depositing the victim and getting on with the rest of the first aid and (self-)rescue plan.

Another advantage of on-rope CB hauling is that by keeping the rescuer's weight constantly on the pull side of the system, the stretch in the rope is eliminated early in the procedure (eg during the first CB rappel) and will likely stay eliminated until the haul is completed. Therefore, the rescuer is not constantly letting the rope recontract with each system reset, expending energy and time pulling on rope stretch at the beginning of each pull sequence, etc. (although this is less of an issue with the cord systems than with the classic on-rope ones). In short, on-rope CB hauls feel much more responsive and efficient. Any raising achieved with them is a real raise, no matter how small, and is not at risk of being lost again when resetting the system.

With on-rope CB systems using additional cord for greater mechanical advantage, the rescuer must deal with (and have with him or improvise with other cordage) enough prusik loops and other gear to install walk-up systems on both the main rope and the pull cord and will need to switch back and forth between the two during the haul (ie have his weight on the cord system for hauling and switch to the rope for resetting). It is important to make a complete switch between the two, especially when switching from resetting to hauling. During testing I encountered a situation where the practical test worked much less well than expected according to the calculations and I realized afterwards that instead of having my full weight on the pull cord, I had left one foot in the foot prusik of the rope system, which decreased the efficiency of the haul. I redid the test, making sure that my weight was 100% on the pull cord and the haul became much easier and consistent with the calculations. Having said that, I generally found that, once each walk-up system was set-up, I quickly got used to the different sequences of pulling, prusiking, switching prusik systems, etc. and did not find that this was a major obstacle to achieving significant raises (although the "D" ratings in the on-rope CB category were given for the length of time and high number of walk-up movements it would take to achieve longer raises).

Of course, my enthusiasm for on-rope CB hauls is very much a subjective evaluation and I wouldn't want anyone just taking my word for it without testing a few of these systems for themselves.

DISCUSSION OF TEST RESULTS

For the most part, the diagrams, calculations and the table comparing the results and the subjective evaluation are self-explanatory.

A few words about system XXXV: although it looks very similar to XXXIV, its hauling capacity is much poorer. I can think of a few reasons for this but there doesn't seem to be much point in making this report even longer by discussing the whys of a poorer system.

If only standard systems are used (as opposed to on-rope CB systems) and no pulleys are available, my tests and calculations reiterate what David said, which is that his cord 2:1 system performs significantly better than the classic on-rope Z 3:1. As mentioned earlier and shown in the diagrams and table, David's system did not do well with weights above my own until I started using additional pull-up loops. Pull-up loops increased the hauling capacity of all systems by a large amount. The highest capacity is usually obtained with the loop in "position1", ie that closest to the rescuer. In this position, the loop has to be slid down more frequently but, since it is always at hand and set on a tensioned rope or cord, adjusting it is quite fast and straightforward. As a general strategy, it appears that it would make sense to select, for a given haul, a system that should deliver the capacity needed without the addition of a pull-up loop. Adding this loop first to position2 can be done quickly and easily to significantly increase the strength of the system if the haul turns out to be harder than expected, without changing the basic characteristics of the system (such as how much you can pull with each stroke, how often you must reset, etc.). If more strength is still needed, a pull-up prusik loop can be placed at position1 instead at the relatively small additional cost of resetting it more often.

If pulleys are available, the Z3:1 regains its advantage over the cord 2:1, especially when taking care to maximize the hauling capacity with judicious use and placement of the pulleys.

CORD 9:1
First, I should mention that I used to advocate in favour of using the "Z pulling on a Z" 9:1 instead of the 5:1, based on tests I did which, as it turns out, were not particularly representative. The testing done recently at the crag and one "tree" test with a 130kg load not reported here indicated that, with a dynamic rope, the classic on-rope 9:1 is really not realistic for vertical climbing self-rescue. With all that dynamic rope zig-zaging through the system, you just end up spending way too much of your time taking up the rope stretch instead of raising the load. So this is my mea culpa regarding the 9:1.

However, between the old tests and the more recent ones, I now feel that a cord 9:1 (XXIV & XXV) should work well in certain very specific circumstances even though I did not test it further. For a cord 9:1 to work, it seems to me the layout should be as simple as possible: a good stance (to avoid the added complications of a separate hanging belay system for the rescuer), with good pro options high enough (2-3m up from the ledge) and, if possible, somewhat spread out horizontally (to avoid having all the pulley points bunched up together). A very long static cord is also essential (at least 12m but longer would be better still).

David lumped the 9:1 in with the 5:1, 6:1 & 7:1 that have poor effective pulling distances. It is true that with the initial pull, the secondary Z 3:1 will bring the entire system to a stop long before the maximum pull distance is reached. However, at this point, if the system is fairly well laid out in front of you, it is quite straightforward to simply pinch the two strands of the cord where shown on the diagrams (>ll<) with one hand to maintain the tension on the primary Z 3:1 while resetting the secondary Z with the other hand. Of course, the second pull will be shorter than the first and the third shorter still, etc. There will come a point when it is no longer worthwhile to just reset the secondary Z and the rescuer will then have to let the load settle onto the progress capture mechanism and reset the primary haul prusik itself but this point is much closer to the maximum possible pull distance than with the 5:1, 6:1 or 7:1.

As a result, I believe that the cord 9:1 retains some potential usefulness as a self-rescue tool reserved for very rare circumstances when a very high MA is needed, the clean set-up conditions are met and a bombproof anchor is available.

HaulTests001

HaulTests002

HaulTests003

HaulTests004

HaulTable

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

Hi, fantastic effort. Just trying to get my head around all the info! I'll then head down the wall to start to play. Thanks from the community for putting the time in.

Might it be possible for you to email me higher resolution versions of the images and table? Thanks again.

ghisino · · Unknown Hometown · Joined Jun 2012 · Points: 0

Hi!

i have been taught rescue systems as a french professional climbing instructor/guide.

my 2 cents is that in the descibed scenario, hauling ratchets are a waste of time, unless you are on a large ledge and you have at least 3 meters to walk back and forth.
(they have a place to help a weak or tired following climber though)

whenever you need to get a seriously injuried partner up fast, option #1 goes as follows.

0)This step is mandatory whatever hauling technique you choose, unless your second can cooperate and unclip.

descend on the live rope to get all draws off (either with 2 prusiks or with a clever variation of the kleimheist knot, done with a 120 cm nylon sling). In case of a traversing line you'll need 8 meters of spare cord and the appropriate technique to get the draws off and put the rope straight.
Ascend back up.

1)tie a backup knot on the dead rope to the power point, with 2-3 meters of slack.
2)place a prusik (kleimheist really) on the live rope, run a sling from the prusik up to a biner @the power point and down to your harness, minihaul the rope.
3)Replace the belay device with any locking pulley mechanism you can use. biner+kleimheist, biner+ascender, mini(micro)trax, etc
4)Detension the minihaul to engage the locking pulley system, get rid of the backup knot.
5)Get on the dead rope with the best ascending system you can use, given the situation. (atc guide+prusik, in euro multipitch setup with double ropes)

congratulations, you can now 1:1 haul your second as if it was an haul bag.
For maximum time efficiency, get as low as you can before ascending back up to the belay.

once wired, for 15 meters of hauling, step 0 should realistically take 2 to 10 minutes.
Steps 1 to 4, 2 minutes max.
Step 5, 4 to 10 minutes.

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

Hi ghisino,
Thanks for that. I can see that working well under some situations but not others.

1. edge friction. If you leave the capture device on the powerpoint then if the anchors are low or back from the edge (as they often are in the mountains) then a 1:1 system isn't going to work, especially when the victim is heavier than the rescuer.
2. if the victim is heavy then even if you pull up on the rope to them at the same time you might well not move them as more mechanical advantage is needed.

ghisino · · Unknown Hometown · Joined Jun 2012 · Points: 0
David Coley wrote:Hi ghisino, Thanks for that. I can see that working well under some situations but not others. 1. edge friction. If you leave the capture device on the powerpoint then if the anchors are low or back from the edge (as they often are in the mountains) then a 1:1 system isn't going to work, especially when the victim is heavier than the rescuer. 2. if the victim is heavy then even if you pull up on the rope to them at the same time you might well not move them as more mechanical advantage is needed.
yes, a combination of the two cases will defo call for another system.
Or, if you are quick enough and the edge of the ledge is close by, an improvised anchor extension so that your "pulley" sits over the edge.

in my opinion and experience #2 alone won't be too much of a problem if the "guide" is strong enough for its weight, unless the weight differential is really extreme (like 50-100).
Remember we are talking about an all-out, desperate effort in a serious rescue situation, not about hauling a pig for X days, nor about helping your dead-pumped buddy to get past a crux.

Just to strenghten my point: in one of the possible ab-rescue technique you are technically hauling at an inversed 1:2 rate for the first few meters, and on a dead vertical line it is totally feasible to get things going with a heavier climber, only on biners (friction!).
It is just odd and extremely strenuous, comparable to doing a series of very heavy deadlifts.

finally, in any way by swapping the belay system to a more efficient pulley you are doing yourself and the injuried climber a favour anyway, even if you will eventually switch to 3:1.
jktinst · · Unknown Hometown · Joined Apr 2012 · Points: 55
David Coley wrote:Hi, fantastic effort. Just trying to get my head around all the info! I'll then head down the wall to start to play. Thanks from the community for putting the time in. Might it be possible for you to email me higher resolution versions of the images and table? Thanks again.
Thanks, David. I'll send the stuff asap. I was not happy with the size of the images when I posted this. I tried to use higher resolution ones thinking that the size would increase but it didn’t. Aside from getting the source material by email, one can also see a larger version of each image by clicking on it. That larger image has a “View full size” button that opens a new tab with the image at full screen size. By opening the four images and the table in separate tabs like that, you can then skip with one click between the text of the post and each large image when you need to consult them.
jktinst · · Unknown Hometown · Joined Apr 2012 · Points: 55
ghisino wrote:...my 2 cents is that in the descibed scenario, hauling ratchets are a waste of time...
Yes, the system you describe is the simplest hauling system possible (1:1 CB haul on the 4th diagram). I would use a different “belay escape and reconfigure” method prior to the haul proper but that’s just personal preference.

This system is great if the victim weighs less than the rescuer. If using a biner as the primary pulley point and the victim weighs about the same and you don’t have edge friction complicating things, the haul is not too hard without a pull-up prusik (just pulling up on the live rope by hand) and becomes fairly easy with one but it gets rapidly more difficult with a heavier victim. Based on my tests, it remains doable with a pull-up prusik and a victim up to about 25% heavier but it quickly gets just plain impossible beyond that (30-35%).

The best course of action is, of course, always to use the simplest/fastest system that will get the job done but if you’re a 50kg rescuer trying to haul a 100kg victim, you’ll be completely wasting your time going for this 1:1, even with a microtraxion (that would let you haul about 80-85kg max).

Leaving aside the microtraxion, if you’re going to do this simple haul with a biner as the pulley point and if the weight differential is such that you actually have a prayer of getting it to work, you won’t need the prusik, ascender or any other progress capture mechanism. With this kind of weight differential, the friction on the biner is all the progress capture mechanism you will need.

Note of caution: I've found that the klemheist and hedden tend to bind themselves fast under heavy loads, making them very difficult to loosen and therefore, very poorly suited for hauling. I only used the classic 3 or 4 wrap prusiks for my tests.
ghisino · · Unknown Hometown · Joined Jun 2012 · Points: 0
jktinst wrote: With this kind of weight differential, the friction on the biner is all the progress capture mechanism you will need.
true!

the progress capture main function is to make it easier to escape the minihaul.

i will have a second look at your calculations but in real life something must be different
(pulling harder than you expect on the live rope? I'm confident one can pull at least half its body weight by getting head down.
I say at least : can you make a pullup by simply grabbing a rope?
One can pull even harder than that if installing a jumar or locking knot on the ropes ever did pullups with additional weight?)

Real life example: one of my rescue instructors was a 55 kg short skinny bastard mountain guide. Like Ramonet, but skinnier.
When testing us on the wall rescues in Presles, he told us that he once 1:1 hauled 3 clients in a row on top of Zulu Demente @Riglos, Spain.
He planned the trick, which saved him a rainy day and also offered a wild swing to the clients (the route is rain sheltered and only the last pitch is hard, and severely overhanging. A 4th client toproped the pitch to get the draws off)
Now, under your assumptions, if i understand them correctly he either was a douchebag, very lucky not to have had any client heavier than 70 kg that day, or a liar?

ps
when i write "kleimheist" i mean this one, called "Machard" in french allo-olivier.com/Photo3Entr…
Not the one where you pass one of the end loops inside the others ("Machard Français")
bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

Folks

Theres a big difference between a fit mountain guide who practices these systems all the time and hauls bags regularly

And someone who may not be so fit, doesnt practice these systems regularly, quite a bit older and with various back/knee issues

Every time ive gotten someone to try to haul me up under realistic conditions, they are either healthy fairly young males that weighed at least as much as me ... Or they simply couldnt

Now im sure trained guides could, but the average weekend warrior is lucky to practice hauling self rescue on rock once a year unless they are aid climbers, especially without the benefit of proper pulleys

;)

jktinst · · Unknown Hometown · Joined Apr 2012 · Points: 55
bearbreeder wrote:...someone who may not be so fit,... , quite a bit older and with various back/knee issues
That's me! ;)

And just to be clear: I really like the 1:1 CB haul but my tests have clearly demonstrated that with my own strength-to-weight ratio and using a pull-up prusik loop and a biner as the pulley, I can't reasonably haul much above 80-85kg with it.

I have no doubt that that guide's strength-to-weight ratio is way above mine.

One of the main points of my long post is that people should do their own testing and should not take my calculated numbers (or, I might add, other people's anecdotal and incomplete evidence) at face value. At most, the numbers might be used simply to narrow down the options to be tested in order to determine the most appropriate system(s) for the kind of rescuer-to-victim weight ratio(s) one is likely to face.
David Coley · · UK · Joined Oct 2013 · Points: 70
jktinst wrote: One of the main points of my long post is that people should do their own testing and should not take my calculated numbers (and, I might add, other people's anecdotal and incomplete evidence) at face value. At most, the numbers might be used simply to narrow down the options to be tested in order to determine the most appropriate system(s) for the kind of rescuer-to-victim weight ratio(s) one is likely to face.
Point well made. I would have everyone who teaches this stuff to always demo it with low anchors at the back of a ledge and a heavy casualty hanging in space, and with couple of pieces on the rope. Might generate some ground truth for all involved.
Guideline #1: Don't be a jerk.

Post a Reply to "Self rescue hauling"
in the General Climbing

Log In to Reply