Some general concepts related to anchors are listed below. (Of note, these are concepts used by recreational climbers and differ from rescue standards which tend to require more redundancy and higher weight-bearing capacity.):
- Should be alive
- Should be big (when you wrap your hands around it, your fingers don’t touch)
- Should be well-rooted (does it shake or sway when you push it?)
- Should not move or shift
- Should be of good quality (won't break, don’t sound hollow when you tap on it)
- Should be shaped in a way that won’t allow your gear to slip off it
- Use the 6 Point Rule or 12 Point Rule to help guide your placements.
- Use separate cracks or placement areas
Anchor Concepts (ASERENE or EARNEST)
- Angles: Unless you are a mathematician who climbs with a protractor and can calculate forces on the spot, you are most likely going to eyeball your angles. Generally, all angles in the anchor should be less than 90 degrees. RopeBook gives a detailed description for those who are interested.
- Strength: Again, you may not be able to calculate the exact amount of force placed on your anchor. However, you should make sure to use enough pieces that can withstand a factor two fall. VDiff gives a good description of falls and kilonewton ratings.
- Equalization: Make sure the force is equal on all parts of the anchor.
- Redundancy: Ensure there is enough backup built into the anchor system in case certain parts of the anchor break or become dislodged.
- Efficient/Timely: Make sure the anchor can be built and taken down cleanly and efficiently.
- No Extension: Make sure that if one piece of gear fails the anchor will not move. One exception is the Sliding X which leads to minimal extension.