Figure 8 Knot
Also called: Figure of 8 Knot; Flemish Knot.
The Figure 8 Knot is used in Canyoneering primarily for creating a "load carrying" loop. Once tied correctly, you can attach a carabiner to it (by using the Figure 8 Knot on a bight) and then use that to clip it into things such as harnesses, anchors, or items (such as to raise/lower things).
This stopper knot is the same as a Figure 8 Follow-through, however, this by itself, is more of a "stopper knot". In canyoneering, these are sometimes used as stopper knots - which is tied at the end of a rope where the group can not verify if the rappelling rope has reached the bottom - and prevents the rappeller from falling off the strand if not paying attention.
Take-away: The Figure 8 knot (and its variations) one that gets frequently in the sport, due to how often you are transitioning to/from rappels and clipping into things/people/anchors.
This is knot is easy to memorize and tie. Everyone in your group should learn how to do this and know the variations of this knot.
Also using the Figure 8 Knot, there is a way of joining (called a "bend") two ropes together but it is called the Figure 8 Bend.
Keeps the person from rappelling off the end of the rope if you are unable to see if the rope has touched the bottom
Easy to tie/untie
Easy to remember
People use this stopper knot at every rappel, every time. This is unnecessary and if deployed like this, the group lacks the understanding of what the purpose is behind the stopper knot.
The usage of this stopper knot by itself is in the "it depends" scenario.
You would NEVER tie this on Class C canyons where there is an active water current.
You may consider using knot when you can't see if the rappelling rope has reached the bottom.
Canyoneering Usage Examples:
Used on the rappelling rope when you can't see if the rope has reached the bottom or not.
Below, I show you three ways on how to tie the knot, via:
2) GIF (animated picture that repeats itself with no-end)
3) Video (from Canyoneering101 YouTube Channel)