Also known as: Ring Bend, Grass Knot and Overhand Follow-through
The water knot is used in Canyoneering primarily for "joining" (called a "bend") webbing together. You can tie a Water Knot using just one piece or two pieces of webbing. Webbing is typically bought in Climbing stores "by the foot" and that's what the community recommends on how to buy it, as you can get custom lengths. This one piece of equipment is probably the one-item in Canyoneering that you will go through a lot of. So get use to the idea and with your wallet.
In canyoneering, when you come to a cliff or drop that needs to be rappelled, you will look for natural anchors (such as rocks, boulders, trees, roots, etc.) to tie your webbing around. (If not, look for man-made anchors). The "Water knot" is THE knot that you will be tieing your webbing together around these anchors.
Remember, that canyon conditions change frequently! And you will need to rebuild anchors (sometimes a lot!). Don't ASSUME that a water knot is safe just because its laying there and looks "ok". Examine it! Being in the sun all day will make it brittle and reduce it's overall strength. And webbing that's been submerged all day (and for many weeks) will need to be changed as well. It will become water-logged and saturated and again reduce its strength. Check for any abrasions or cuts in the webbing. Also make sure that tails from the water knot are minimum 3" in length.
The Water Knot is quite simple to tie and everyone in your group should know how to tie this.
Conclusion: This is an absolute VITAL knot that everyone in your group should know how to tie! 30-feet/person is the recommended length that everyone needs to carry in a canyon. You may use all of it, or none, but as we commonly say here, "it depends"; along with we just don't know what to expect as canyons change frequently.
To build it, you take the working end of the rope, create a loop, and put the end of the rope through the bottom of the loop to the top and pull tightly on both ends of the knot (also called "dressing the knot"). That's it!
It is safe!
It is easy to tie and remember.
It is easily identifiable by most canyoneers.
We leave a tail because with each rappel, the knot
Hard to untie. If you are have to untie it, using a knife to cut the webbing maybe be faster.
There is a stronger knot in term of pounds per force and that is the double-fisherman. But once the double-fisherman has been loaded, it is very hard to untie if done with webbing.
Leave three inches of tail on both strands of the water knot. Any more than 6 inches is considered ample.
Just like webbing, check every water knot, every rappel, every time. And when it doubt - just rebuild it! It takes literally two extra minutes to tie it correctly.
Replace webbing if it looks cracked, cut, has abrasion marks, brittle, stiff, or sun-bleached.
Canyoneering Usage Examples:
Using this knot only to tie webbing around natural or man-made anchors.
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)