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Diagram

Double Double Uni Knot

Double-double Uni · Doubled Double Uni

Joining braided main line to a mono or fluorocarbon leader with two Uni knots slid together, the braid side tied with the line doubled.

Line-to-line · Intermediate · Braid / Monofilament / Fluorocarbon · 4 steps

ApplicationsHow to tie it
Double Double Uni Knot, finishedDouble Double Uni 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. Double 30 cm of braid into a 15 cm double line and lay it along the leader endBraid folded back on itself into a double line lies alongside the end of a heavier leader, the braid's bend and the leader's tag pointing opposite ways.
    1Bend of the doubled braid
    2Leader tag end
    3Two braid strands together
    Move 1 of 1Double 30 cm of braid into a 15 cm double line and lay it along the leader endYou should now see: Two braid strands lying together along the leader, the bend of the doubled braid pointing toward the leader's standing part.

    Step 01

    Double about 30 cm (12 in) of braid back on itself to make a 15 cm (6 in) double line, then lay the doubled braid alongside the end of the leader, the two ends pointing opposite ways.

    You should now see

    Two strands of braid lying together along the leader for about 15 cm (6 in), with the bend of the doubled braid pointing toward the leader's standing part.

    If it goes wrong

    The two braid strands drifting apart or twisting around each other, so later wraps go on as single strands. You see a gap open between them.

    Fix: Pinch the doubled braid flat and run it between finger and thumb until both strands lie side by side, then lay it back along the leader.

    Why: Every wrap in step 2 is made with both braid strands together, which is what separates this knot from a basic Double Uni.

  2. Loop the doubled end back over both lines and pass it through the loop 8 timesThe doubled braid end crosses back over itself into a loop and winds eight open doubled turns round the leader and the doubled braid inside the loop.
    1Eight doubled turns
    Move 1 of 2Loop the doubled end back over both lines and pass it through the loop 8 times
    Pull the doubled end to close the 8 wraps onto the leaderThe eight doubled turns close into a tight barrel on the leader, each turn two braid strands lying side by side.
    Move 2 of 2Pull the doubled end to close the 8 wraps onto the leaderYou should now see: A neat barrel of 8 doubled-braid wraps snugged down on the leader, each wrap showing two strands side by side.

    Step 02

    Cross the end of the doubled braid back over itself to form a loop, pinching the crossing and the leader together. Pass the doubled end through the loop 8 times around both lines, then pull it to close the wraps.

    You should now see

    A neat barrel of 8 doubled-braid wraps snugged down on the leader, each wrap showing two strands side by side.

    If it goes wrong

    Wraps crossing over each other, or the two braid strands splitting apart inside a wrap. The barrel looks lumpy and the strands show as separate turns.

    Fix: Loosen the wraps by pushing them back toward the loop, straighten the doubled strands, and pull the doubled end again slowly.

    Why: NetKnots closes this barrel onto the leader before starting the leader side. Once closed it holds its place while you tie the second knot.

  3. Loop the leader tag back over both lines and pass it through the loop 5 or 6 timesThe leader's tag doubles back into a loop over the doubled braid and winds five open turns round both lines inside it, facing the other way.
    1Five turns of leader (or six)
    Move 1 of 2Loop the leader tag back over both lines and pass it through the loop 5 or 6 times
    Pull the leader tag to close the 5 turns into a second barrelTwo closed barrels sit on the overlap, the long doubled-braid barrel on the right and the shorter leader barrel on the left, with bare line between.
    1Braid barrel
    2Leader barrel
    Move 2 of 2Pull the leader tag to close the 5 turns into a second barrelYou should now see: A second, shorter barrel of leader wraps closed down a short way from the braid barrel, with bare line between the two.

    Step 03

    Tie the same knot with the leader tag: form a loop back over both lines, pass the tag through it 5 or 6 times around both lines, and pull the tag to tighten. Use fewer wraps on heavier leader.

    You should now see

    A second, shorter barrel of leader wraps closed down a short way from the braid barrel, with a little bare line between the two.

    If it goes wrong

    Leaving a barrel only partly tightened. When the knots are pulled together the loose wraps slide unevenly and the tag can draw back through.

    Fix: Pull each tag again until its wraps stop moving before sliding the knots together. If the leader wraps have crossed, undo that knot and tie it again.

    Why: Heavy leader is stiff and does not bed down well over many turns, so the wrap count drops as the leader gets heavier.

  4. Wet both knots and pull leader and main line apart until the barrels meetPulled from both standing lines, the braid barrel and the leader barrel slide along the overlap and butt against each other.
    Move 1 of 2Wet both knots and pull leader and main line apart until the barrels meet
    Trim the leader tag and both braid tags closeThe finished double double uni: a long doubled-braid barrel butted against a short leader barrel, with three short trimmed tag ends.
    Move 2 of 2Trim the leader tag and both braid tags closeYou should now see: The two barrels butted together with no bare line between them, and short tags that do not catch when run through your fingers.

    Step 04

    Wet both knots and pull the leader and main line in opposite directions until the two barrels slide together. Trim the leader tag and both braid tags close.

    You should now see

    The two barrels butted against each other with no bare line between them, and short tags that do not catch when you run the join through your fingers.

    If it goes wrong

    Stopping with a gap between the barrels, or trimming the tags before the final pull. A gap shows as bare line between the two knots.

    Fix: Wet the knots again and keep pulling steadily until they touch. If a barrel slides apart instead, cut the join off and tie it again.

    Why: Pulled together, the two barrels jam against each other. Leaving the tags on until after this pull lets you see that neither knot has slipped.

HTH · Reference layout

Double Double Uni Knot — finished-state checks, on the shared reference layout

Double Double Uni Knot — finished-state checks, on the shared reference layout
Hook the Horizon reference plate
Failure modes

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

Uni family

A barrel that is formed, then slid to the eye or the other barrel.

  • !Barrel locked short of the eye or the other Uni
  • !Crossed wraps in the barrel
  • !Tag buried back into the barrel instead of exiting
Fails when
  • !A knot left partly tightened, so its wraps slide unevenly and the tag draws back through
  • !The two knots slide apart instead of meeting when the lines are pulled
  • !Braid strands split inside the wraps, so the braid grips as a single strand
Geometry

  • Too few wraps on the doubled-braid Uni

    Slick braid walks

    The extra braid wraps are why this is not a Double Uni · step 02

  • One Uni closed before the other

    A hinge that clicks in the guides, then parts

    Dress both barrels together so they butt · step 03

  • Braid not doubled through the barrel

    That is the other Uni — not this join

    Doubled braid through the whole barrel is the grip · step 01

If you saw this

  • Join clicks in the guides or one side walks

    Check

    • ?Doubled braid through the barrel
    • ?Both barrels butted

    Then

    • →Retie with a real double
    • →Trim after the seat

  • Finished check failed — One side single-line only

    Check

    • ?Both doubled sides form compact barrels
    • ?Barrels meet squarely
    • ?Tags exit cleanly

    Then

    • →Retie. Missing the double on one side creates an asymmetric weak join.

  • Too few wraps on the doubled-braid Uni

    Check

    • ?Slick braid walks
    • ?Inspect step 02

    Then

    • →Retie. Do not dress a defective structure and call it seated.

  • One Uni closed before the other

    Check

    • ?A hinge that clicks in the guides, then parts
    • ?Inspect step 03

    Then

    • →Retie. Do not dress a defective structure and call it seated.

  • Braid not doubled through the barrel

    Check

    • ?That is the other Uni — not this join
    • ?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
Braid to leader
Not ideal for
  • Micro guides that punish bulk
  • When a slimmer Alberto or FG already seats
Common mistakes
  • Braid strands splitting apart, so wraps go on as single strands
  • Sliding the knots together before each one is fully tightened
  • Too many wraps on heavy leader
  • Trimming the tags before the final pull
Alternatives
  • Double Uni KnotBeginner

    Reliable way to join two lines of similar or moderately different diameters

  • Alberto KnotIntermediate

    Joining braid to a monofilament or fluorocarbon leader, or two other lines of different diameter

  • FG KnotAdvanced

    Joining a braid main line to a leader, such as fluorocarbon, with a slim, tapered join that runs through the rod guides

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