Hey gang, let’s talk about the quad anchor today. The quad anchor is a wonderful little anchor that allows for variability in the direction of pull. We can think of this as a variable vector anchor.
To build a quad anchor with a double-length sling, first double up your sling and pull it tight, keeping the bar tack off to one end, and then tie 2 knots, each one just off center. At this point clip the 2 ends up to the bolts and see where your knots lay. We want to be even to the side of the center. If it’s not quite perfect, you can simply adjust it. Once you have your knots adjusted where you would like them to be so you have a few inches in between the knots, we can now take note that our master point is composed of 4 strands. To use this anchor, simply clip half the strands. When I build a top-rope system off of a quad, I like to use 1 carabiner on 2 strands and a second carabiner on the other 2 strands, thereby incorporating all 4 strands. Be certain that the gates of the carabiners are opposing, and then clip the rope into the 2 carabiners.
If I were to use this anchor for multi-pitch climbing or belaying from above I would clip my pear-shaped carabiner to half of the strands, orienting it so that the basket is down and the gate is facing me. At this point, I can clove hitch myself in. This leaves the remaining strands free and available for use for whatever utility you may need.
Rick Wagner, AMGA Rock Instructor