Page 10 - D. Raleigh "Knots and ropes for climbers"

Double Overhand Knot.
Common Uses
Stopper knot in the end of a belay rope
Stopper knot in the end of a rappel rope

Double Overhands used as stopper
knots in a rappeling device.
Overhand on a Bight

This version of the Overhand is the most misused of the climbing knots. Foolish climbers use it as a
middleman's knot or to anchor the rope. In both cases, there are far better knots. Use the Overhand on a
Bight for either purpose, and you'll quickly learn that it's about impossible to untie after it's held body
weight, especially when the rope is wet.

Overhand on a Bight.