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Post by gregggagliardi on Mar 2, 2013 16:21:46 GMT -8
The simplest way to tie into a belay anchor is with the rope. In more recent years climbers have tied in (or backed up their tie-in) with lanyards of various kinds. The first ones were daisy chains that were meant for aid climbing. Metolius and others came out with stronger, full strength chains. These are nice but also unforgiving in the event of a fall. In fact some of the worst possible climb forces on a belay anchor can occur if someone climbs above the anchor on such a lanyard and then falls on the anchor. The forces can easily exceed the strength of the belay anchor. Mike Gibbs and others at Ouray Mountain Rescue have tested numerous lanyards. The best one, in terms of reducing forces on the anchor, is the Purcell Prusik. www.caves.org/section/vertical/nh/53/RiggingForRescue-LanyardsPartII-2006.pdfThe Purcell Prusik is a versatile piece of gear that also serves as a great adjustable device for carabiner ice axe belays, rappelling and for rope ascension. If we are going to recommend a lanyard let's recommend the safest and the most versatile one. Gregg
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Post by nicklyle on Mar 7, 2013 0:47:59 GMT -8
I would like to see a picture of the Purcell Prussik. What does this lanyard look like?
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Post by gregggagliardi on Mar 7, 2013 9:43:14 GMT -8
Go to the link in my message. It contains a good video on how to construct the Purcell Prusik.
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Post by dougsanders on May 15, 2013 7:52:08 GMT -8
The 6 mm Purcell prusik was introduced in the late 1980's by Arnor Larson, developer of the Rigging for Rescue (RFR) approach to static-rope rescue.
Recreational climbing and RFR have different approaches to rope work; techniques are not always compatible with the other's approach. The RFR approach utilizes, in part, 10:1 system safety factor and static ropes of 11 mm or 12.5 mm diameter. Climbers use smaller diameter dynamic ropes, smaller loads and are fanatical about weight.
I believe the primary motivation for Arnor's new prusik design 'Purcell' was to provide 10 kN strength required by RFR for a 1 kN rescuer load with the 10:1 safety factor. This is 2X as strong as the Texas.
I was introduced to the Purcell in 1993 as an intermediate climber/instructor who took the RFR course. The RFR rescuer carries 3 different sized Purcells. They are used as a 3-prusik rope ascension system, personal anchors, and various attachments to a litter. As much as I have wanted to incorporate the Purcell into my climbing, I found it to be a single use item which was bulkier, heavier and overbuilt when compared to other options. From time-to-time I have revisited the Purcell always coming to the same conclusion.
Our Texas prusik foot loops can be modified into a Purcell variation that is less bulky. Rather than a stopper knot and half a double fisherman create each foot loop with a tight Helical prusik (without a stopper knot.)
This modified Helical-Texas prusik can be used for: (1) traditional foot prusik; (2) 1 or 2 (redundant and perfect for 2 bolt sport/crag anchors) legged, adjustable, personal anchor; (3) 2 adjustable legs for multi-pitch belay direction change from belaying above to belaying below from bolts; and, (4) perfect (long cord with 2 loops, with center loop removed) for escaping the system after an emergency tie-off using a prusik-munter-mule, eliminating the need for a prusik and sling.
Furthermore this saves the weight of a dedicated lanyard/personal anchor. Have used this set up for nearly 20 years.
Mike Gibbs is the 3rd owner of RFR. Mike's tests are very severe and are not representative of a typical fall. Am not aware of accident data supporting changing from the widespread practice of using static lanyards, especially in the Cascades; the manufactures are still cranking them out by the zillions. F8 suggests there have been accidents.
What any prusik approach has going for it is length adjustability, nylon cord (energy absorption), a hitch that will slip under high forces (more energy absorption), and low cost.
However, in addition to its positive attributes we should consider the negatives as well: The Purcell may not be tight enough, allowing unplanned extension, potentially dropping the climber over an edge; it is a single use device for which there are substitutes (clove hitch when ascending and slings when awaiting ones turn for rappelling; or, manufactured lanyard); comparably bulky; loops can snag; and, it is one more, rarely (perishable skill) used, tie to learn, in competition for the new climbers taxed learning capabilities.
Personally, in the interest in climbing efficiency, simplicity and weight savings (best practice), I do not think a dedicated lanyard/personal anchor is necessary; use clove hitches when ascending and slings while awaiting ones turn for rappelling or other odd needs.
In the world of personal anchor absurdity, I am seeing some Basic students being taught to use personal anchors, in addition to a clove hitch, on flat ground at the base of a pitch. This makes no sense and reflects poorly on The Mountaineers.
In summary, I believe a modified version (needs tests) of Purcell would be simpler and lighter for climbing than the rescue version, if we really need lanyards/personal anchors.
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Post by jasonmartin on May 19, 2013 6:38:02 GMT -8
Generally speaking, recreational climbers overuse personal tethers or lanyards. AMGA courses (and as a result most guide services) currently teach that individuals should use their rope to tie directly into the anchor with a clove-hitch on multi-pitch climbs. This allows one to be able to adjust their rope tremendously. A Purcell Prusik only allows one to make minor adjustments in where one is able to stand.
In the single pitch setting, there is more of a need to have an ability to tie into the anchor quickly with something other than the rope. This is often because of the fact that one may be approaching a climb from the top to set-up a top-rope or may be approaching from below to clean a sport climb. Many recreational climbers currently use the PAS for this. Though the majority of guides simply use slings.
Conterra Rescue Systems and Rescue 3 International also teach the use of the Purcell. These companies, as well as Rigging for Rescue, have a focus on team based technical rope rescue, not on recreational climbing... Though Rigging for Rescue does a lot of programs for NPS climbing rangers, so their techniques have bled into that crowd.
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Post by gregggagliardi on May 20, 2013 12:32:46 GMT -8
It is hard to beat tying in with a clove hitch.
The Purcell, however, is nice for quick adjustment at the belay and also for transferring the load from the anchor to the rappeler's device in some situations. It is also a handy adjustable foot loop for rope ascension (one of it's original purposes). Tied on a short piece of looped cord it makes an adjustable FiFi or nice "dogging draw" for hang dogging on sport climbs. Finally, when tied on one of the three legs (the longest) of a rescue spider made from a cordelette it makes it easier and safer to transfer the load from the anchor to the device on a multiple tandem rappels.
Perhaps the best reason to recommend it is that it is easily and quickly tied on a loop of ordinary 6mm accessory cord, which means that it doesn't require any special single purpose gear or the added expense of a daisy.
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