The anchor is the foundation of climbing safety. Every belay, every top-rope setup, every multi-pitch rappel — all of it depends on anchors that hold. An anchor failure cascades into catastrophic consequences. This guide covers the principles of anchor building: equalization, angles, redundancy, and the specific systems that have been tested by thousands of climbers over decades.
The Three Principles
Anchor building rests on three non-negotiable principles: equalisation, redundancy, and minimal extension. Equalisation means the load is distributed across all anchor points proportionally. Redundancy means any single point can hold the load if another fails. Minimal extension means if one piece pulls, it doesn't affect the others.
Equalization sounds simple: share the load. In practice, it requires adjusting anchor geometry so that all pieces see similar loads. The ideal anchor has anchor points within a 30-degree angle from the master point, with the master point directly above the load. A wide-angle anchor — where the two pieces are far apart — multiplies forces on each piece dramatically.
Anchor Types: Bolts, Trees, Gear
Bolted anchors are the simplest: two quicklinks or maillons from two bolts, connected to a master point with a绳, locker, or cordelette. The configuration depends on bolt spacing. A pair of bolts spaced 20-40cm apart can be equalised with a绳; wider spacing requires a cordelette or equaliser. If only one bolt exists, back it up with a personal anchor to an independent piece.
Natural anchors — trees, boulders, rock protrusions — require evaluation of the anchor's integrity. A dead tree is not an anchor. A living tree with good root flare and trunk diameter is strong. A chockstone wedged solidly in a crack is strong. The evaluation skills come from experience and from understanding failure modes.
The Cordelette System
The cordelette is the most versatile anchor building tool. An 18-20 foot loop of 7mm or 8mm cord, it can be configured as an equalette (sliding-X), equalised cordelette, or knotted cordelette. The sliding-X (equalette) is the strongest configuration, automatically equalising across the anchor points.
The configuration: tie the cordelette in a loop with a double fisherman's knot. Place three or four pieces, clip them to the loop, tie a knot at the master point, and clip the belay device to that knot. The knot should be positioned so that the loop's sliding action equalises the load. Practice at ground level before using this system at height.
Equalising with Quickdraws
For simple two-bolt anchors, two quickdraws (gates opposed) clipped to each bolt and to a locker at the master point is an acceptable top-rope anchor. The quickdraws should be opposed (opposite-facing gates) to prevent cross-loading. This configuration is fast and is acceptable for top-rope anchors where the forces are low.
For lead anchors, the quickdraw configuration is insufficient because fall forces are higher. Use a绳 or cordelette with proper equalisation for lead climbing anchors.