Hey MP, the other day a friend and I were working on some anchor-building techniques, and he built his anchor like in the pictures here. I have never been taught this way, not have I seen people teach this way. After looking at it, I couldn't figure out a reason why it wouldn't work other than it makes it harder to tie a knot to make the anchor redundant because the cord is halved. What's your guys' input?
I use that method when when I am at a 2 bolt anchor except I just use the rings instead of passing the bight through the biners. The only time I use the biners in this manor is when I am going to have to pull the rope through the rings to rap. That way you dont have to worry about nylon on nylon friction. Does that make sense?
edit: and yes I tie a figure eight for my master point.
agreed with scott--you need to tie it off to maintain redundancy....as for halving it--if you were at a stance in which you wanted to shorten your anchor (keeping your belay device high is more comfortalble, etc), you could halve it. if you wanted to lengthen your cordelette and therefore lower your anchor point (for example, if your pieces were all several feet above you), then you'd only clip one strand of your cordelette thru the biners....
along with having to double the amount of cord you're using that'll probably make tying the master point knot a pain in the ass since there will be so much cord in there. it will work, but probably not worth it. also, if you dont have an exceptionally long cord your anchor might be impossible to make if your anchor points arent close together. in short, it will work but probably isnt the best method for every case
I personally would not use this method being that you have to tie a knot. Without the knot any one strand breaks and this anchor fails (already mentioned). My reasoning is that I use the sliding x pretty often and I don't want to accidentally not use a knot when I really should have. But out of curiosity you mentioned two different ways to build an anchor but I only see one?