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Diagram

Constrictor Knot

Constrictor hitch · Constrictor bind

A bind that must not walk. Harder than a clove; expect to cut it off.

Binding · Intermediate · Polyester / Nylon rope / Polypropylene / Natural fibre · 4 steps

ApplicationsHow to tie it
Constrictor Knot, finishedConstrictor Knot, finished

Finished structure

Drawn from a rope model of this knot: which strand passes over which comes from where the rope actually lies.

  1. Pass the end around the object and bring it across over the standing partThe rope goes once around the post and its end comes back across the front, lying diagonally over the standing part.
    Move 1 of 1Pass the end around the object and bring it across over the standing partYou should now see: One turn around the object with the end lying diagonally across the standing part.

    Step 01

    Pass the end around a round object, then bring it across over the standing part so the two cross on the front.

    You should now see

    One turn around the object with the end lying diagonally across the top of the standing part.

    If it goes wrong

    Tying it against a flat surface, or trying to use it to join two ropes. On a flat face the turns cannot grip and the knot loosens.

    Fix: Tie it around something curved, such as a rope end, a sack neck or a pole. To join two ropes, use a bend.

    Why: The knot needs a curved surface so the crossing turn can press down on the knot beneath it.

  2. Take the end around a second time, close beside the first turnThe end goes around the post a second time, the same way round, and comes back to the front below the first turn.
    Move 1 of 1Take the end around a second time, close beside the first turnYou should now see: Two turns side by side, with the diagonal crossing lying over them on the front.

    Step 02

    Take the end around the object a second time, close beside the first turn.

    You should now see

    Two turns around the object side by side, with the diagonal crossing lying over them on the front.

    If it goes wrong

    Letting the first turn slacken or drift while you make the second, which leaves a gap between the turns.

    Fix: Hold the crossing under your thumb and push the turns together before you tuck.

  3. Tuck the end under itself and on under the first turnThe end tucks under the riding turn and under the first turn, locking the two ends in an overhand beneath the diagonal.
    1Under the first turn
    Move 1 of 1Tuck the end under itself and on under the first turnYou should now see: The end and standing part leave opposite ways, crossed under the diagonal — not parallel.

    Step 03

    Tuck the end under itself where it crossed the standing part, then carry it on under the first turn, so it passes under both turns.

    You should now see

    The end and the standing part leaving the knot in opposite directions, crossed over each other in an overhand beneath the diagonal turn.

    If it goes wrong

    Tucking the end under itself only. That is a clove hitch: lift the diagonal and the two ends lie side by side instead of crossing.

    Fix: Loosen the end and carry it on under the first turn as well.

    Why: The diagonal turn clamps the overhand underneath it. That clamp is what grips, and it is why the knot is so hard to undo.

  4. Pull both ends hard; plan to cut the diagonal when it has to come offThe finished constrictor: two turns locked by a riding turn, the ends crossed under it.
    Move 1 of 1Pull both ends hard; plan to cut the diagonal when it has to come offYou should now see: Turns bedded into the object, no gap under the diagonal, and a knot that does not turn.

    Step 04

    Pull both ends hard to close the knot down on the object. To remove it later, cut the diagonal turn where it lies over the other turns.

    You should now see

    Turns bedded into the object, no gap under the diagonal, and a knot that does not turn when you twist it.

    If it goes wrong

    Expecting to untie it after pulling it hard. Once set, it is often impossible to undo with your fingers.

    Fix: Cut it off over the other turns. If the binding has to come off later, tie a slipped constrictor, finishing the end as a bight so a tug on it releases the knot.

    Why: Cutting the diagonal over the turns beneath it lets those turns protect the rope or object from the blade.

Failure modes

When this family fails, it fails as these. The recovered end still outranks the name.

Grip-hitch family

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
Fails when
  • !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
Geometry

  • 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

If you saw this

  • 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 family

Same failure class, different geometry. Open the plates — Diagnose still starts from the symptom.

This failed — start Diagnose

Why this knot

What it earns its place with, what it costs, and what to reach for instead.

Best for
Reefing or binding
Not ideal for
  • A bind you must release (reef knot)
  • A join
  • Around a finished piece you cannot sacrifice
Common mistakes
  • Tucking the end under itself only, which leaves a clove hitch
  • Tying it against a flat surface
  • Letting the first turn drift while making the second, leaving a gap between the turns
  • Expecting to untie it after pulling it hard
Alternatives
  • Reef KnotBeginner

    Binding two ends of the same line around a sail or bundle

  • Clove HitchBeginner

    Hanging a fender off a rail or stanchion, or a quick tie you stay beside and adjust

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