Well we’re talking about anchors. Let’s talk a little bit about the term bombproof. What is a bombproof anchor? Those of you in the profession of rescue work, and sometimes in the industry we refer to what’s a bombproof anchor? Well, it’s something that’s really strong that can pretty much hold everything. And looking at this tree right here in a rigging lab, it is truly bombproof. It is a big heavy piece of timber that is well bolted to the ground, it has four three quarter inch bolts on it. This is not going anywhere. So this is strong enough that we can put everything on it. We have the main line, we have the belay line on this, that’s what you can do with a bombproof anchor. You can put the main and the belay on the same anchor, as long as there’s different attachment points. A bombproof anchor can hold everything, and usually that’s a team decision.
Let’s move over to the A frame over here and talk about that part of it a little bit. Let’s take a look at the sideways A frame we have here with the Arizona vortex. Although we’re not going to get into the specifics on how to rig this, I would like to continue to talk on whether it’s bombproof or not. Is this a bombproof anchor? The conventional wisdom is that you don’t put your belay line into an artificial high directional, like a tripod, which can be notorious for tipping over. You don’t want all your eggs in one basket. But you notice here we have the main line and we have the belay line on fixed pulleys at the top of this A frame. Why? Well, in my eyes I’m looking at a couple of things. Is this artificial high directional going to tip over? It definitely has the rating I want.
If we’re looking for something that’s in the realm of nine to ten thousand pounds of strength, we’re very close to that. So this is without question very strong. I have to ask myself the question, is it going to tip over? And I can look at my guying system. I know that it’s guyed down to very substantial anchors, I feel very confident that it’s not going to tip over. Another thing that I look at is the resultants of these pulleys. They’re within close proximity, only a couple degrees off the footprint. Now, remember what we talk about with the footprint, that’s defined by the compression members, the front leg and the back leg. In this case with an A frame that footprint is that single line between the front and back leg. These pulleys, if we were to put a laser light on them, they would be within a couple of degrees of this single line right here.
So we’re maximizing the compression by keeping that resultant within a couple degrees of the footprint of this A frame. I feel very confident that could not tip over. I would deem this a bombproof anchor, at least as a high directional, and therefore that’s how I justify putting the belay line permanently fixed up at the top of this A frame.
Products being used in this tutorial:
- Arizona Vortex is a portable artificial high directional system with the ability to be a tripod, a monopod, and a bipod all in one. With a precision two point head, the CMC Arizona Vortex can be rigged in various applications such as, a standard tripod or advanced set ups such as an A-frame, gin pole or multiple other imaginative configurations.
- CMC MPD is the innovative multi-purpose device that allows the user to go from lowering to raising without changing hardware.The CMC MPD is a UL Classified pulley, descent control device and belay device. A high efficiency pulley with an integral rope-grab mechanism optimizes the best of both worlds.
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Peace on your Days…