Page 84 - Joseph B. Healy "The Pocket Guide to Fishing Knots"

The Duncan Loop (also called the Uni-Knot) is useful for many other
applications, too. Use the Duncan Loop instead of an Arbor Knot to

attach line to a reel arbor. Use the same knot when attaching a leader to
a hook, a swivel, or a three-way rig. This MVK (Most Valuable Knot) is
strong and tests out at more than 95 percent breaking strength. The
benefit is that it holds up under the steady pressure of a sounding and
running fish, as well as the pounding jerks associated with a jumping,
tugging fish. No matter how your favorite species fights, the Duncan Loop
provides an edge. But here’s what I like best, and perhaps this is why it’s

known as both the Duncan Loop and the Uni-Knot—it’s a loop knot as
well as a fixed knot. Seat the Duncan Loop a quarter of an inch above
your fly or bait, and it’ll function as a loop. Streamer and nymph
flyfishermen, big fly saltwater anglers, and live bait anglers love the
additional natural movement that comes from a loop knot. When a fish
hits, the Duncan Loop slides until it snugs down to the hook eye. Then it

miraculously transforms into a fixed knot. If you’re tying on a plug, a soft
plastic, or a stickbait, you can always seat the knot to the hook eye.
Three names for one knot with universal applications—you’ve gotta love
it.