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Post by Deling Ren on Feb 18, 2013 9:55:28 GMT -8
As of 2013, we teach belay escape with 1 mule knot (the initial knot to free hands). The weight loading knot and the back up knot are figure-8s. This makes subsequent rescue very difficult because the figure-8 is loaded. In the intermediate course, students need to unlearn what they have learned in the basic course.
Should we change it and teach using 3 mule knots?
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Post by Tony Tsuboi on Feb 18, 2013 11:21:56 GMT -8
In Everett, we teach the belay escape with a transition of the load termporarilly to a load releasing hitch - i.e. prussik on rope tied back to the anchor via mariner knot. IMO, we should really teach the full cycle of a transition back onto a munter mule.
Irrespective of which load releasing knot, I think this is essentialy what you're suggesting.
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Post by karlthemer on Feb 21, 2013 10:23:57 GMT -8
Having run both sessions of FT2 this past weekend, I can report that most instructors are in fact teaching belay escape with at least two mule knots. The load is transferred onto a Munter-Mule (i.e. a load-releasing hitch) and not a solid knot such as a figure-8. I think it would be helpful for us to have a short, proper discussion on the topic to correct any "standard technique" which might be out there. I have updated some of our online course documents to remove references to putting the load on a figure-8. We should remember that this is a rarely used (but important) rescue skill which should not be overly complicated or long in process, but at the same time should never introduce any major disadvantages for rescuers - which is what happens when we load a knot. The goal should be that if a guide or other professional were to see our technique, that person would agree it is safe and efficient without introducing new problems. Bottom line, if students can tie the initial Mule knot to get hands-free, then they can also tie a second Mule knot. If the second Mule knot is "too hard", then simple logic suggests that the first Mule knot is also too hard and we should go back to passing the rope around the belayer's back and wrapping it around the foot three times - that would be really unfortunate. Two mule knots as a minimum; I personally like using three. Never transfer the load to a knot. If the mule knot is difficult, practice more.
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Post by gregggagliardi on Mar 5, 2013 11:55:29 GMT -8
I agree with Karl. We need to teach rescue techniques that provide a fairly seamless transition to subsequent rescue activities. We also need to teach basic students the fundamental first parts of more complex rescue scenarios that they will learn or encounter in the future. One of the benefits of using the MMOH is its flexibility as a load releasing device and the fact that it can be used in all rescue situations regardless of the location of the belay anchor. It is truly a universal, all purpose tool, and a fundamental principle in all self-rescue.
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Post by adamnelson on Mar 17, 2013 18:11:38 GMT -8
I agree that the loading the figure 8 on a bight should be removed from the basic curriculum and we should move to the 3 munter-mule system. Using two munter-mules works but still weights what would be the backup figure 8 on a bight if the prusik slips. If you can tie one, 3 can be tied. Additionally, Having the students get completely out of the 3 munter system and lowering the weight provides a great introduction to load releasing hitches and lowering systems which will be built upon in intermediate creating a fluid transition.
I like using the Mariners knot as well; however, it does add a level of complexity.
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Post by dougsanders on Jun 5, 2013 8:00:14 GMT -8
Do prusiks slip? Or, do they only slip when poorly dressed, poorly sized or too few wraps? In the rescue community we hold 2 and 3 person loads with a single prusik and no back-up in the raising system. (In a sense there is a back-up in the redundant belay.) . There have been a number of prusik slow pull and dynamic tests by independent entities. The need for a back-up is not a recognized risk in the rescue community.
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Post by jasonmartin on Jun 6, 2013 9:55:22 GMT -8
Prusiks tend to slip under three different circumstances:
1) If they are poorly dressed. 2) If they are "bumped" by something, such as a belay device. 3) Under a 9kN load.
In the AMGA, it's an automatic fail if a live load is ever left on a single prusik hitch. If there are two prusiks, then it is acceptable to leave a load hanging on the system. However, we usually tie the rope off on something behind.
My experience with the rope rescue community is that they tend to have two separate prusik cords on the system in order to provide some redundancy.
Jason
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