|
Post by gregggagliardi on Oct 17, 2013 12:48:53 GMT -8
How about adding the Canadian Drop Loop method for crevasse rescue to Freedom 9 as the preferred technique for crevasse rescue. Actual tests conducted by rescue professionals have shown that 3 to 1 techniques are often not sufficient for crevasse rescue. Also the preferred sequence for a rescue is to start with the simplest method (2 to 1) before proceeding to more complex hauling systems which is easily done with the start to a drop loop system. Finally, rope entrenchment is the rule when folks fall into a real crevasse, which is a huge problem for the traditional Z-pulley system. I expect that there will be quite a lot of resistance to abandoning the Z pulley system for the Canadian Drop Loop system, mostly because it is poorly understood and also because it is believed to be a more complicated, "advanced" technique. Here are some advantages: 1. It works with a stuck, entrenched rope 2. Due to the above point, it can be used when brake knots are tied between climbers to help hold a fall. BTW: Even three brake knots on the lead person's and end person's rope can successfully stop or substantially slow most falls. See link below: m.youtube.com/user/AlpinismeENSA?&desktop_uri=%2Fuser%2FAlpinismeENSA3. The first part of the drop loop system is a 2 to 1 system on a fixed (read that no pulley) anchor, which permits rapid construction and rescue when 2 to 1 mechanical advantage is enough, which would be the case when there is a second rope team to assist the first. 4. When fully assembled it is a 6 to 1 system over a protected (non-entrenched) lip 5. The same system works well with a 2-person rope team (no need to teach a second system for 2-person teams; one system can cover it all) 6. It is not any harder to learn than a Z pulley system (give it a try)
|
|
|
Post by jasonmartin on Oct 17, 2013 14:31:55 GMT -8
I don't think you should give up on the Z system. You're right that a Drop C or some other similar system would be a good place to start and then to work up to the Z system, but abandoning the Z would be a poor choice.
The issue with the Z system isn't that it doesn't work. It works really well. The issue is the way that it is employed. It doesn't work will if you're hauling on a strand that is entrenched, or worse, entrenched with a butterfly knot in the lip. If people learned the system from a conceptual standpoint instead of from a prescribed standpoint, they could still use a Z to pull someone out on the backside of the rope.
The unfortunate part of trying to teach things conceptually is that an individual usually has to have a prescribed method dialed before understanding a conceptual method.
Jason
|
|
|
Post by gregggagliardi on Oct 17, 2013 15:01:14 GMT -8
The Canadian Drop Loop is pretty darn nice. Rope entrenchment is not an issue; alpine butterfly knots (or other braking knots) can be used without worry since the line to the climber is anchored to a fixed point, and it is ultimately a quickly constructed 6 to 1 system if more pulling power than a drop C is needed. What I like about it best is that it obviates having to teach more than one system. Mountaineers "learn" the Z system and C drop as basic student then learn the Z x C later as intermediate students. Why not teach one highly versatile system.
I especially like your point about conceptual versus rote learning. Though the former requires more time, practice and even experimentation to fully comprehend the underlying concepts, it teaches component skills that can be creatively deployed to handle a myriad of climbing problems. It is one thing to have a good tool and quite another to be able to use it creatively, which is what climbing problems often demand. How to incorporate conceptual learning into a climbing training program is an intriguing challenge.
|
|
|
Post by dougsanders on Oct 30, 2013 7:45:11 GMT -8
I favor the 3:1 to any 2:1 for several reasons. All in all the 3:1 is more universal and has far fewer potential disadvantages.
2:1 potential pitfalls:
CARRIED ROPE: No short glacier ropes here. 2+/5th of rope must be carried by end climbers. This is a 2+ lb. weight penalty that must be carried by every team on every glacier climb even though the probability of use is very small.
Traditionally the rope is carried in a Kiwi coil. Kiwi is burdensome. A bit time consuming to build and needs to be built 'just right.' Worn, it interferes with clothing adjustments and is a hassle at breaks. It is inseparable while on a glacier.
The Kiwi coil has the potential to snag ice or snow during fall, pull loops and even entangle the victim. The Kiwi coil is likely to interfere with efforts for the hanging victim to zip-up, add or adjust clothing and to prusik with. The victim cannot remove the Kiwi.
The Kiwi may impede the victims ability to reach and fasten the lowered pulley-binner.
DECISION TO USE 2:1: I presume most crevasse victims fall through weak snow cover rather than into a wide open crevasse like those where most crevasse rescue practices take place. As such there will be no communication with the victim until the rescuer can get near to, or over, the hole. So, a 2:1 might be built even though the victim was unconscious or otherwise couldn't use one.
VICTIM: The 2:1 is dependent upon the victim being able to see, reach and fasten the lowered pulley-biner to their harness. This presumes the victim is alive, conscious, not covered in fallen snow, upside down, wedged, has one good arm with finger dexterity, and has access to both the lowered pulley-biner and their harness.
LOWERING THE PULLEY-BINER: The rescuer has to be able to lower the pulley-biner to the victim. The rescuer has to be directly above the victim and must have a clean straight path to lower the pulley-binner. The rescuer may have to lean out over the opening to manipulate the rope. The crevasse sides may not be smooth or there may be snow debris such that there is no direct path or the rope hangs.
The 2:1 may snag during raise or knock down snow since it is in a 'V' formation.
MECHANICAL ADVANTAGE: It is possible that additional teams are not available to help. Say a snow bridge collapsed with teams on both sides; or, some separation has taken place. The 2:1 won't be enough for 2 pullers.
DISCUSSION: The 2:1 has it's place and it may be the best and obvious solution in some instances. I think of the 2:1 as a condiment, the 3:1 as the main course.
The 3:1 has a deserved reputation for entrenching. Everett Basic Course students learn these systems during late May, probably the peak of entrenching conditions. The class may have 10-15 set-ups. I can't recall any system becoming hopelessly entrenched. Placing the ice axe close to the edge helps. Yes, it can take some effort, shoveling, shifting, etc. to overcome entrenching. Yes, it could add minutes to the extraction. In some cases overcoming edge entrenching is a perfect opportunity to add a 2:1.
The 3:1 is harder to learn and is perishable. However, it has been the mainstay for decades and thousands of Basic climber know how to build them.
|
|
|
Post by gregggagliardi on Oct 30, 2013 10:41:38 GMT -8
I was afraid that my first post on the Canadian drop loop (CDL) might be misunderstood. This post clarifies a few things about it. BTW the comments are excellent points and some of them actually support use of the Canadian Drop Loop system. 1. The CDL is a theoretical 6 to 1 system when completed. 2. The first step in setting up the CDL is a 2 to 1 system, which may be all that is required for many situations, especially if the victim can assist the rescuer. In fact some call this 2 to 1 system an "assisted raise" 3. The original rope to the victim is not involved in the raise. It is fixed to the rescue anchor. Entrenchment is therefore not an issue. This also means that brake knots can be tied on the rope to the about-to-be victim. Recent testing shows that even a few of these will greatly slow and even quickly stop a crevasse fall, which reduces the likelihood of injuries to the victim and makes rescue easier and faster. Once you view these tests you will want to tie a few brake knots on your side of the rope if you are the lead climber. 4. The best textbook explication of the CDL is Houston and Cosley (2004). See link below: www.mountaineersbooks.org/Alpine-Climbing-P258.aspx5. For the brake knot tests see: m.youtube.com/user/AlpinismeENSA?&desktop_uri=%2Fuser%2FAlpinismeENSAHouston and Cosley are well respected senior AMGA/ UIAGM guides. Their book, published by Mountaineers press, contains a wealth of information that could improve several chapters in Freedom of the Hills. The reason that I posted on the CDL is because it is a best practice for crevasse rescue. If one was going to learn only one system for crevasse rescue this is it. It combines the best of the C pulley and Z pulley systems in a package that can be flexibly, quickly and efficiently deployed by rope teams, including 2-person rope teams, to address the problem at hand. It is easy to learn. I invite those who are skeptical about the CDL to personally check it out.
|
|