Knots/Bend knots/Water knot

The water knot (also tape knot, ring bend, grass knot, or overhand follow-through) is a knot frequently used in climbing for joining two ends of webbing together, for instance when making a sling.

Water knot
NamesWater knot, Tape knot, Ring bend, Grass knot, Overhand follow through
Categorybend
Typical useTo join webbing for climbing
CaveatEnds should be left long, knot should be tightened and inspected before each use. Difficult to untie.
ABoK number
  1. 296

Tying the water knot

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Water knot before tightening

It is tied by forming an overhand knot in one end and then following it with the other end, feeding in the opposite direction.

The ends should be left at least 3 inches  long and the knot should be "set" by tightening it with full body weight. The ends can be taped or lightly sewn to the standing parts to help prevent them from creeping back into the knot.[1]


Security

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Testing has shown the water knot to slip very slightly, but very consistently, with each load and unload cycle. In tests using 9/16 in  tubular webbing, repeated loading and unloading with 250 lbs  caused one of the 3 in  tails to work back into the knot in just over 800 loading cycles. When the water knot was statically loaded with 200 lbs  no slipping was observed. These results validate the need to leave long tails and inspect water knots before each use.[2]

References

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  1. Craig Luebben, Knots for Climbers (Evergreen, Colorado: Chockstone Press, 1993), 19.
  2. Tom Moyer, Water Knot Testing, 1999 International Technical Rescue Symposium, 1999. ([1] accessed 2007-04-07.)