Constrictor Knot
Interlock · Constriction
Does not pick a knot
This page does not pick a knot for you. DNA, molecules, quantum braids and vortices stay off Decide.
Finished structure
No drawing of this exact knot yet. The written steps are the reference.
When this family fails, it fails as these. The recovered end still outranks the name.
Directional bite on a standing part — slide-test before you trust it.
- !Turns on the wrong side of the load
- !Failed slide-test, still used
- !A clove where a rolling or icicle third turn was the job
- !It is tied on a flat surface, where the turns cannot grip and the knot loosens
- !The end is tucked under itself only, leaving a clove hitch without the clamped overhand that grips
- !It has been pulled hard and needs to come off, as it is often impossible to untie and has to be cut
Left as a clove — no riding-turn tuck
Bind walks; this is not a constrictor
The tail must tuck under the standing part and the first turn · step 03
Expected to untie after a hard dress
Knife job on a bind you needed to release
Animated Knots: usually cut rather than untied · step 04
Used as a join
A bind is not a bend
Pick a sheet bend or Zeppelin if you needed a join · step 01
Bind walks, or will not come off when you need it to
Check
- ?Crossed riding turn over the two ends
- ?Tail under both
Then
- →Finish the tuck
- →Cut it if it has seated
- →Use a reef knot if you needed a release
Left as a clove — no riding-turn tuck
Check
- ?Bind walks; this is not a constrictor
- ?Inspect step 03
Then
- →Retie. Do not dress a defective structure and call it seated.
Expected to untie after a hard dress
Check
- ?Knife job on a bind you needed to release
- ?Inspect step 04
Then
- →Retie. Do not dress a defective structure and call it seated.
Used as a join
Check
- ?A bind is not a bend
- ?Inspect step 01
Then
- →Retie. Do not dress a defective structure and call it seated.
Same failure class, different geometry. Open the plates — Diagnose still starts from the symptom.
What holds it
- ·Reef / square is a binding knot around a parcel. Opposite-direction throws lock; same-direction throws are a granny and walk.
- ·Johanns et al. (2023) locate that difference in friction, geometry and plastic set — not in crossing count. Granny is not among these knots.
What topology does not predict
- ·Reef is not a bend for two working ropes under load. Seamanship already forbids that job.
- ·Surgical throw security is not a Palomar rating.
- ·No suture-material number is copied onto nylon dock line.
Not for
- ·Joining two ropes as a bend — use a sheet bend or a recognised bend family
- ·Letting a surgical paper pick your fishing knot
- ·A bind you must release (reef knot)
- ·A join
Same pattern, different job
- Diagram in reviewClove Hitch
Constrictor is a clove hitch plus a riding turn that jams.
- Johanns et al. — Strength of surgical knots (Sci. Adv., 2023) — Square vs granny is friction, geometry and plastic set — not crossing count.
- Reef knot (Wikipedia) — Binding knot. Capsizes. Opposite-throw pair is the granny — not in these knots.
- EPFL — Mechanics of the ideal surgical knot (2023) — Public summary of Johanns et al. Alternating throws lock; same-direction throws walk.
- Animated Knots — Constrictor Knot (Rope End Method)
- ITS Tactical / Imminent Threat Solutions — How to Tie the Constrictor Knot - ITS Knot of the Week HD — Cited tying video already attached to this record.