Farrimond Friction Hitch
This is a quick-release hitch that is related to the Prusik, but made from a single line instead of two. It makes a good knot for a tent ridgeline or a clothesline where you need to establish and adjust tension. Once tied, the Farrimond Friction Hitch can be slid up and down the standing part of the rope to raise and lower tension. And when you’re ready to untie it, a simple tug of the working end of the rope will undo it easily.
To tie the Farrimond Friction Hitch, start with the standing end of your rope tied off to another object, such as a tree. Pass the working end around a second object or tree (represented as the dot in the diagram). Form an underhand loop, then wrap the loop around the standing part of the line twice. You should end up with a small loop still protruding. Form a bight in the working end of the rope, insert it in the small loop you created, and pull everything tight. Slide the knot to increase tension. To untie, just pull the tag end.