So I had an exciting near miss during an introductory caving trip recently and wondered if anyone had any views / comments:
A group of four of us are taking it in turns to ascend a fixed ladder under instruction from the guide, with each person tied to the end of a safety rope running up through what I understand to be a toothed cam pulley on a fixed belay. At the top of the ladder the guide is taking in the rope and explaining that if anyone falls then the pulley cam will catch them. As way of example he suggests to the last person ascending the rope that they lean back, at which point the rope runs clean through the pulley with the toothed cam bouncing up and down and the poor beginner bounces his way down only to be caught by the guide mere inches above the ground. Thankfully serious injury was avoided.
Now the guides quick reaction in managing to grab the rope (also thankfully injury free) definitely saved the chap who fell from a couple of broken legs but it was definitely a very close thing and could have easily been much nastier. A few seconds later and (apart from hitting the ground) I very much doubt anyone would have been able to hold the rope at speed. There was no back-up to the pulley and probably a foot of slack rope between the chap who leant back and the pulley. I also reckon there would have been a fair bit of slack rope between the guide who was belaying and the pulley. The pulley was something similar to this
http://www.petzl.com/en/pro/progress-capture-pulleys/pro-traxion with some really mean teath, so I don't think it's similar to the old GriGri problem I've heard of where the rope would sneak through if your fall started off slowly.
Anyone any experience of using these pulleys before for anything other than hauling gear? Any suggestions for ways the system should have been backed up? It seemed a bit risky to trust just one pulley - granted a belay plate is a bit similar but at least you always have that locked off, whereas from the look of it the toothed cam on the pulley would only bite if shock loaded hard.
Iām just a lowly sport climbing boulderer so my technical rope work is rudimentary at best, so comments appreciated.