“Wrap 3, Pull 2” - about the strongest anchor possible
The "wrap 3, pull 2" has long a preferred anchor method with rescue teams for rigging on trees or similar round objects. What are some benefits to this anchor?
Super strong, because the load is distributed among many strands of webbing instead of one or two. (This anchor tests around 35-40 kN.)
Load distributing, to a certain extent
Pretty much zero force is applied to the knot, which otherwise would be the weak point of the system
But, it has a few downsides:
Require a LOT of 1 inch webbing
Can take a while to tie, if you don't practice it much
Is not redundant (when tied in the typical way)
Strengthwise, it’s overkill for most recreational climbing situations. (If your carabiner is rated around 20 kN, you shouldn't need an anchor that can hold 40.)
But, if you are a rescue person, or want to use it in a high load situation like river rescue or maybe pulling your car out of the ditch, it can be handy to learn.
You need is a long (10+ feet) length of 1 inch webbing.
Note that you can’t make this anchor with a sling that's sewn into a loop. You have to have a single long piece of webbing.
To make the “wrap 3 pull 2” anchor:
Make three wraps with the webbing around a large solid object. This is probably a tree.
Tie the free ends in an overhand knot (or water knot) with at least 3 inches of tail.
Now, pull / wiggle the two strands of the webbing that don’t have the knot in them, leaving the actual knot against the tree.
Clip your master point carabiner to these two strands extending away from the tree.
Diagram: Freedom of the Hills, 7th edition, The Mountaineers Press