The thief knot is easy to undo quickly (thieves used it to swiftly untie the reins of their horses). It is used when a rope must be released rapidly on a sailboat in order, for instance, to hold back the boom, or when it is necessary to have both hands free to work on the boat.
Make a bight along the rope and pass it behind the length of line you want to release.
STEP 2
Make a second bight on the free strand of rope, which is on the side that stays tense, and pass it through the first bight.
Make a third bight with the free strand and pass it through the bight made during Step 2.
Tighten by pulling the strand on the tense side. To undo the knot, just pull the free strand.
