Page 95 - Patty Hahne "The Pocket Guide to Prepper Knots"

Pros: One can easily attach a prusik knot to a rope that is
already under tension. It is useful because when a load or
tension is applied to it, friction helps prevent it from sliding
on the main rope. When the tension is removed, the prusik
knot can easily be slid to another position along the rope.
Cons: This is another knot where one of the positive char-
acteristics can also be a negative one. This is because the
knot can be unintentionally moved from the position that
it was originally tied onto the main line if tension isn’t kept
applied to the knot. This knot may also be prone to slipping if
the rope you are using happens to be wet or icy since there
won’t likely be enough friction to hold the knot in place.

Again, remembering that this knot relies on the friction
between the two knots to hold it in place, it can be more
or less effective depending upon the type of rope used.

How to tie it:
1. Decide how large you would like the loop to be. This is
determined by the number of times you would like to
wrap the loop around the main rope. More wraps will of
course require a larger loop. This will make more sense
as you continue reading about how this knot is used.
2. Cut a length of rope several inches longer than you want
the overall diameter of the loop to be.

Instructions for Tying Prepper Knots 89