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Knot · Joining two lines

Double uni knot

Join two lines of similar or different diameters, for example a braid and a leader: two uni knots, each tied around the other line, slid against each other.

Technical sheet
Indicative strength
  • 75 % of line strength, five turns on each side, braid to fluorocarbon
  • 6 % of line strength, four turns, nylon to fluorocarbon: the knot failed
Source: Field & Stream, “Tie the strongest fishing knots”, John Merwin’s tensile tests, updated in 2026. Indicative values: they vary with the line and the care taken when tightening.
DifficultyEasy
UseJoining two lines
Compatible linesnylon, fluorocarbon, braid

Diagram in preparation

The step-by-step drawing of “Double uni knot” is being checked; follow the steps below.

Step by step

  1. Overlap the two lines by about twenty centimetres, in opposite directions
  2. With the end of the first line, tie a five-turn uni knot around the second, then tighten it
  3. With the end of the second line, tie a uni knot around the first, then tighten it
  4. Moisten, pull on the two main lines: the two knots slide together until they butt up
  5. Trim the ends short
The test before fishing

Once tightened, the two knots must butt up against each other. Allow at least five turns, and seven to eight on the braid side.

Similar knots

Rigs that use it

Which fish

All knots · The technical notebook