Uni and double uni

What it connects

The uni knot ties a line to anything with an eye, and that is the version most anglers know. Tied without sliding it closed, it leaves a fixed loop. Tied around a hook shank, it is a snell. Tied around the spool arbor, it holds new line. Tied around another line and matched by a second uni tied around the first, it becomes the double uni, a line-to-line connection that joins braid to a fluorocarbon or mono leader or two lines of similar size. Animated Knots lists exactly those uses: snelling, creating loops and end-to-end joins.

The knot's name belongs to Vic Dunaway, who published it as the uni knot in 1970 and built a whole "Uni-Knot System" around the idea that one knot, adapted, covers every connection an angler needs. It was Norman Duncan's knot first, the Duncan loop, and it is the grinner knot in British use. Animated Knots, NetKnots and Outdoor Life all give that history.

Basis: consensus (Animated Knots, NetKnots, Outdoor Life, In-Fisherman reprint of Dunaway)

Compatible lines

• Monofilament and fluorocarbon: yes. NetKnots calls it a good and dependable knot for monofilament to terminal tackle, and Sunline's starting point is 5 to 6 wraps for most mono and fluorocarbon.
• Braid: yes, with more wraps. Sunline moves to 7 to 8 wraps in thin or slick braid so the knot has more bite and does not slip, and Dunaway wrote that the system is by far the best way to tie small-diameter braided lines. In Salt Strong's head-to-head pulls the uni beat both the Palomar and the clinch on braid.
• Braid to fluorocarbon or mono leader, as the double uni: yes, the knot's most common line-to-line job. NetKnots: 6 to 8 turns in the braid, 5 or more in the mono, fewer as the mono gets heavier.
• Fly tippet: works as a loop knot or a snug knot, but fly anglers reach for the non-slip loop and the improved clinch by habit, and Art Scheck's hand tests found the non-slip loop beat the Duncan loop every time.

Basis: consensus; official on the maker's wrap guidance

Best uses

• A terminal knot on mono or fluorocarbon when you want an alternative to the Palomar that does not require passing the lure through a loop: big hard baits with trebles, jigs on heavy fluorocarbon, swivels.
• A terminal knot on braid, where it tests strongly and never slips if wrapped enough.
• The braid-to-leader connection for anglers who want one knot family, the double uni, on drop shot, shaky head, Ned rig and slip float spinning setups.
• A fixed loop on a jig or a crankbait, by stopping before the knot slides down to the eye.
• Snelling a hook, and tying new line to a spool with two or three wraps.

Basis: consensus

Difficulty

Easy, and easier than the improved clinch for many hands, which is NetKnots' own remark. The uni is tied in open air with the tag end, the wraps go inside a loop you can see, and nothing has to be threaded through a small opening at the end. The double uni is two of them. The skill is in snugging each knot fully before sliding, and in keeping the wraps stacked rather than crossed.

Basis: consensus; editorial

Strengths

• One knot, every job. Learn it on the bench once.
• Ties well in braid, where clinch-style knots slip.
• Easy to tie with cold hands, in the dark, and with a long tag.
• Adjustable: the same tie makes a snug knot or a loop depending on where you stop sliding it.
• Dunaway's claim, carried by In-Fisherman, is that the system keeps its strength on a sudden jerk where other knots that test over 90 percent on a steady pull break at 50 or 60; that is his statement and no method is given, but it is a reason tournament anglers such as Aaron Martens give for preferring it on braid.

What the published tests show, each with its method:

Reading across them: a well-tied uni on mono is at or near the top on one machine test and well behind the clinch and Palomar on another; the wrap count, the line and the tier matter enormously, which is what Sport Fishing's spread from 99 percent to 31 shows. On braid the uni is the knot that tests consistently well in head-to-head pulls. As a line-to-line knot it is a step behind the blood knot in mono and well behind the FG and Alberto family in braid to leader. Treat any single percentage as a data point, not a law.

Basis: official on the test figures, each from the named test; editorial on the reading

Weaknesses

• Not the strongest at any one job. The Palomar and clinch beat it on mono in one machine test; the FG and Alberto beat the double uni for braid to leader in every published comparison we read; the blood knot beat it mono to mono.
• The wrap count has to suit the line. Too few in braid and it slips; Aaron Martens, in Bassmaster, wraps 10 to 14 times in light braid and warns that in fluorocarbon more than 7 or 8 wraps weakens the knot and causes break-offs.
• Bulk. Two barrels butted together make a connection fatter than an FG or Alberto, and Sunline notes it is not the first choice when a long leader must run repeatedly through small guides.
• Crossed or badly stacked wraps stop it seating cleanly, and a fluorocarbon uni cinched fast and dry heats the line; both are Sunline's cautions and both apply to every knot on this site.

Basis: consensus

When another knot is better

• Braid straight to a bare hook or jig: the Palomar is quicker and, in Sunline's words, often the cleaner choice; Salt Strong's braid pulls favor the uni. Either is sound; pick the one you tie well.
• Braid to a fluorocarbon leader that will run through the guides: the Alberto, or the FG for the slimmest, strongest connection.
• Mono to mono, or tippet to leader: the blood knot or a double surgeon's.
• A fly that should swing: the non-slip loop.
• The dropper on a drop shot: a Palomar with a long tag, because the tag becomes the dropper.

Basis: consensus; editorial on the recommendations

How to tie the uni knot

The orientation below assumes the hook is held in the left hand and the tag end worked with the right. The "standing line" runs back to the reel; the "tag end" is the free end; the "doubled line" is the pair of strands between the eye and the loop you form.

Watch it tied. Animated Knots' uni knot page steps through the loop beside the standing line, the wraps inside it and the slide to the eye, and NetKnots' double uni page animates the two knots being tied and slid together. We read both alongside the steps below, and they agree.

1. Pass about 8 inches of line through the hook eye and lay the tag end back alongside the standing line, so you have two parallel strands running away from the eye. Then bring the tag end back toward the eye in a circle, laying it over the two strands, so the tag end, the two strands and the circle form a loop beside the standing line. NetKnots' words: double back parallel to the standing line and make a loop by laying the tag end over the doubled line.
2. Working inside that loop, wrap the tag end around both strands and through the loop. Make 6 turns in mono or fluorocarbon (NetKnots and Berkley), 5 (Animated Knots), or 7 to 8 in braid (Sunline); Sunline's starting point for most mono and fluorocarbon is 5 to 6, with 4 to 5 enough in heavy line. Each turn passes around the doubled line and out through the loop, stacked beside the last.
3. Wet the knot. Pull the tag end to snug the wraps together into a barrel. Snug it hard at this stage; In-Fisherman's note is that snugging tightly here is essential to the knot's strength.
4. Slide the barrel down to the eye by pulling the standing line, and seat it with a firm pull. Or stop short and leave a small loop, which is the loop version. Trim the tag.

Animated Knots describes what happens as it closes: the outer wraps become internal and vice versa. That transformation is normal and not a fault.

Basis: consensus (NetKnots, Animated Knots, Berkley, Sunline, In-Fisherman)

How to tie the double uni

Two uni knots, each tied around the other line, then slid together.

1. Overlap the ends of the two lines by 6 to 8 inches, lying side by side.
2. Take the tag end of one line, double it back over both lines to form a loop, and wrap it around both lines and through the loop. NetKnots' count for lines of similar size is 3 to 4 wraps; for braid to a mono or fluorocarbon leader, 6 to 8 wraps in the braid. Wet it and pull the tag to snug that knot against the other line.
3. Repeat with the other line's tag end, in the opposite direction, around both lines and through its own loop: the same number of wraps for similar lines, or 5 or more in the mono or fluorocarbon leader, fewer as the leader gets heavier.
4. Wet both knots. Pull the two standing lines in opposite directions so the two barrels slide along the lines and butt together. They must meet squarely; a gap means one was not snugged.
5. Trim both tags close.

NetKnots' double double uni doubles the braid before tying for a stronger grip in slick line: 8 wraps with the doubled braid, 5 or 6 with the leader. Berkley's uni-to-uni gives 6 to 8 turns on each side and the same slide-together finish.

Basis: consensus (NetKnots, Berkley, Sunline)

Testing and trimming

• Pull-test every uni before you fish it. Sunline's instruction is to always pull-test the knot, and Florida Sport Fishing's testers put most knot failures down to technique, not design.
• Look at the barrel. Stacked wraps lying beside each other are right. A wrap crossing another, or a barrel that would not slide, is a retie.
• On a double uni, the two barrels should touch with no gap and no twist between them.
• Trim close on mono and fluorocarbon. On braid, leave a short stub rather than a flush cut.

Basis: consensus; editorial on the braid stub

Rigs and techniques that use it

• Braid to leader, as the double uni, on the finesse spinning setups in line systems: drop shot, shaky head, Ned rig, wacky rig, and slip float rigs for crappie.
• A terminal knot on fluorocarbon for a jig or a Texas rig, and on big hard baits that will not fit through a Palomar's loop.
• A loop knot on a jig or crankbait when you want a freer action and do not want to learn the non-slip loop.
• Line to the spool: two or three wraps, Dunaway's count, which is the arbor knot in all but name.

Basis: consensus

Sources and how confident we are

Sources

• Uni Knot — NetKnots — the four tying steps and 6 turns; Duncan loop and grinner names; "easier to tie than the improved clinch"; the loop option.
• Double Uni Knot — NetKnots — the steps, 3 to 4 wraps for similar lines, 6 to 8 in braid and 5 or more in mono; Roland Martin's preference; sliding the knots together.
• Double Double Uni Knot — NetKnots — the doubled-braid variant, 8 wraps and 5 or 6, the reasoning.
• Uni Knot — Animated Knots by Grog — Norman Duncan, Vic Dunaway and the Uni Knot System; five wraps; snelling, loops and end-to-end joins; the wraps turning inside out as it tightens; its 82 and 75 percent figures, stated without a method.
• Fishing Knots 101 — Berkley — the uni and uni-to-uni steps, six turns and 6 to 8 turns.
• Uni Knot Fishing: When to Use It — Sunline America — 5 to 6 wraps for mono and fluorocarbon, 7 to 8 for braid, 4 to 5 for heavy line; wetting, stacking and the pull test; when the Palomar or FG is better.
• Braided Fishing Line Knots — Sunline America — the double uni described; bulk through small guides.
• The Uni-Knot System — In-Fisherman (Vic Dunaway) and Uni-Knot — In-Fisherman — Dunaway's turn counts (six for a hook, four or five for a snell or loop, two or three for spooling), the braid remark, snugging tightly, the jerk-versus-steady-pull claim and the "over 90 percent" line-to-line claim, both without a method.
• How to Tie a Uni Knot — Outdoor Life — the Ashley Book of Knots, Duncan and Dunaway history; 6 passes in thin line, 3 to 5 in thick.
• Tackle with Aaron Martens — Bassmaster — 10 to 14 wraps in light braid; 7 or 8 wraps in fluorocarbon and the break-off warning; his jerk-strength opinion.
• Winning Knots from Sport Fishing's Third Reader Knot Challenge — Sport Fishing Magazine (Doug Olander) — the IGFA Instron test, measured line breaks, the five-turn uni at 99.26 percent, the spread of uni entries in mono and braid.
• Uni, Palomar or Improved Clinch? — Florida Sport Fishing — the Diamond machine test on 60 lb mono, three pulls, 67.2, 66.7 and 50.3 lb; technique as the usual failure.
• Palomar Knot vs. Uni Knot with Braided Line — Salt Strong — 10 lb braid, 18.36 against 20.21 lb, 8 percent.
• Clinch Knot vs. Uni Knot — Salt Strong — five wraps each, three line types, the clinch ahead on fluorocarbon and mono, the uni ahead on braid.
• Blood Knot vs. Double Uni — Salt Strong — six trials, 20 and 30 lb mono, blood knot 13 percent stronger.
• The Best Fishing Knots of All Time — Salt Strong — the double uni rated up to 30 percent weaker than the FG in the author's tests; the uni not quite as strong as the Palomar.
• The Strongest Fishing Knots for Each Type of Line, Tested — Field and Stream (John Merwin) — back-to-back uni knots at 75 percent against the J knot's 83 for braid to fluorocarbon.
• Fly Fishing Knots: The Last Link — MidCurrent (Art Scheck) — hand-pull comparisons in which the non-slip loop beat the Duncan loop every time.

Related

Techniques

• Texas rig
• Jig
• Slip float

Knots

• Palomar knot
• Alberto knot
• Non-slip loop

Line

• Line systems
• Leaders and tippet