Extremeophile wrote:Having just completed NCRC Level 1 training, I learned and practiced the tandem triple wrap Prusik belay (T3WP Belay), and this is commonly paired with a Prusik-minding pulley for progress capture on a haul, and a radium load releasing hitch (RLRH) to allow the rope to be unweighted if the belay has to hold a load. This belay system is the only one they endorse for a rescue load (more than one person), and is even more complicated to tie properly than it is to spell. I kept thinking that a Grigri would replace this whole system - belay a haul, belay a lower, release a weighted rope, and pass the whistle test. It could be rigged with much less equipment and in a small fraction of the time with far less opportunity for error. Is there a reason not to use this that I'm missing? I don't accept the argument that it's a specialized piece of equipment... 30' of 8mm cord for the RLRH, Prusik knots and a Prusik-minding pulley are also specialized equipment.
Good question, Derek. You're not the first person to wonder about this.
As I recall, the short answer is the GriGri is only rated for single person loads. That said, it is being used as a safety belay device for cave rescue in some parts of the UK. See
this post:
paul wrote:The Gri-Gri is usable as a belay device for caving ropes (used by my local Cave Rescue organisation) however, care must be taken to always hold the controlling rope until safely locked-off as it may not autolock on a sudden load and also it releases suddenly when depressing the handle after autolocking. Care must be taken to prevent the autolocking being released unintentionally by allowing the device to press against any surface.
I don't have the reference at hand, but I remember reading something about rescue load drop tests with the GriGri. Apparently it holds, but often a sharp tap to the handle with a solid object is required to release it again. Similar types of device with higher load ratings like the Petzl Rig and I'D may fare better, but I'm not sure.
Remember, NCRC teaches "a" method - not the only method. The rationale behind curriculum choices is a complicated thing in itself, way beyond the scope of this discussion. Suffice to say most of the rope rescue content is based on tried and tested standard techniques from the above ground technical rescue world, carefully blended with "what works" in the cave environment. The level one class is primarily focused on that first part, and subsequent levels tend to delve into more options. For example, when you come back for level two you'll likely be spending a little more time belaying single person loads with something even simpler than a GriGri - the Munter hitch.