Anchor Analysis – A Foreplay Case Study
Noticed this creative top-rope set up yesterday set on Foreplay (5.5), above Bedroom Amphitheater. The photo is a little difficult to see: basically, the rigger girth hitched tubular webbing to two trees, a few feet up the trunks, then used opposite and opposing quickdraws to create connection points for the rope. He/she ran the climbing rope directly through these quickdraws, about 20' from the edge of the cliff.
This rigging setup is a close cousin of the infamous "American Death Triangle," so-called because the arrangement increases forces on the anchor points, instead of distributing force evenly between two points. While I can't know what the rigger was thinking or what equipment was on hand, I suggest two improvements at minimum:
- Get more out of the webbing. Instead of tying the webbing into a big loop with a water know, untie the loop and use it as a long, single strand. The anchor legs will now be much longer, reducing the angle between the legs and thus the force on each anchor point (trees, in this case).
- Connect the webbing ends together in a single overhand knot. This eliminates the "death triangle" configuration, strengthening the anchor and reducing extension should one anchor point fail.
- Lower the point where the webbing connects to the tree. A tree is strongest at its base, not 3 feet up. Strengthen the anchor and be kind to the tree by moving the webbing down the trunk. Admittedly, this does create a sharper angle as the rope goes over the edge, which would make for even worse rope drag, so this point is debatable in practice.
These changes improve the anchor strength, but leave us with a master point 15 feet away from the cliff edge. Not only will the rope be difficult to pull or belay, but the running the rope over the sharp edge will add significant wear.
Without more webbing or static line on hand, I don't think the climber could have done more with these trees. The rock where he topped out is almost void of features, so obvious options are absent. A better choice, however, would have been to build an anchor in the rock face south of Foreplay, next to the top of Orgasm, where there's lots of good gear opportunities on a great ledge.
If the climber had more webbing or static line, it would improve his setup tremendously to bring the anchor legs all the way to the cliff edge, extending his master point over the edge so his climbing rope ran freely.