Knot guide · friction
How to tie a prusik knot
Of all the knots in the paracord repertoire, the prusik is the one with real mechanics. It is a friction hitch: a loop of cord wrapped around a host line so that loading the tail squeezes the wraps tight against the host — the harder the pull, the harder it grips. Release the load, push the wraps with a fingertip, and the same knot glides anywhere along the line. Mountaineers trust it with their lives; campers will find it the most useful knot on any tarp rig.
Why it works
Capstan friction: each wrap multiplies the grip of the previous one. Two wraps around a 10 mm host hold a light load; three wraps hold a person; four are available for icy or slick lines. The prusik grips in both directions along the host, which distinguishes it from one-way hitches and makes it reversible — lower a load, then re-position and lower again.
Tying it, step by step
Make the loop
Form a closed loop of paracord about 60–90 cm around, joining the ends with a secure bend (a double fisherman's, or a melted and whipped splice). The loop's joining knot will travel with the prusik — keep it small.
Wrap three times
Pass the loop behind the host line and wrap it around the host three full turns, stacking the wraps neatly side by side — not bunched, not overlapping. The loop should be roughly half the diameter of the host line; if your host is 3 mm paracord itself, use micro cord for the prusik.
Dress the wraps
Hold the host line and slide the wraps together so they touch. Smooth, parallel wraps are the difference between a prusik that bites and one that slips under load.
Load it
Clip a carabiner through the loop or tie your guyline to the tail and pull. The wraps cinch onto the host instantly. To move it, take the load off and push the wraps from either end — they will slide freely.
Field applications
- Adjustable tarp guyouts — prusik on the ridgeline, guyline to the stake: re-tension wet nylon in one push, no re-tying.
- Lantern and gear hangers — a prusik loop slides to height on the ridgeline and holds a swinging load without sliding down.
- Progress capture in hauling — the prusik acts as a ratchet in a piggyback haul system.
- Double-loop ladder — series of prusiks on a fixed line make slip-proof footholds for river crossings.
Safety line: a prusik grips nylon-on-nylon, but paracord is not rated climbing rope, and neither is this a climbing lesson. For life-safety rigging use rated cord, rated hosts and real instruction. Around camp, the prusik's genius is convenience: a knot that holds like a clamp and moves like a zipper.
Troubleshooting
Slips under load: add a wrap, or use a thinner loop cord — friction scales with the mismatch between diameters. Will not slide when slackened: your wraps are crossed; re-dress them. Frozen or wet host: go to four wraps. And if the loop cord is the same diameter as the host, nothing will save you — downsize the prusik cord or use a lanyard-knot-based fixed loop on a braided host instead.
The prusik's cousins
Three siblings cover the jobs the classic prusik does less well. The klemheist is tied with a single strand (no loop needed) and grips beautifully on icy or wet hosts while releasing more easily. The autoblock wraps around the host inside a carabiner — the standard choice for backup friction on a rappel line, and equally handy as a sliding tensioner on a clothesline. The blake hitch grips one-way and slides when tended, which arborists favour for moving up a fixed line. Around camp you will reach for the classic prusik nine times in ten, but knowing the klemheist alone — tied from the tail of your guyline with no extra cord — has rescued more sagging tarps than any gadget sold for the purpose.
A note on the name
The knot carries the name of Dr Karl Prusik, an Austrian mountaineer and music professor who published the wrapping technique in 1931 — a reminder that the most useful hardware in the mountains turned out to be knowledge, folded cord and friction. Ninety years later the same three wraps still anchor tarp ridgelines, hang bear bags and ratchet loads on trailers. Few knots so small do so much work.