The story of a Knot: the Duncan Loop – Uni Knot – Grinner

first published here on the 15th of November 2011 with the diagram above and great video tutorial, i was very pleased when Norman Duncan, the creator of this classic knot joined in on the comment section.
an even better surprised happened yesterday when Norman graciously sent in the story and evolution of his ‘Duncan Loop’ that was missing from the original link that i had found.

now, when talking about the ‘Duncan’, most anglers around the world will say that’s it’s just a Uni knot and in the UK it’s typically referred to as the ‘Grinner’.
they are indeed the same knot as explained here on animatedknots.com
this all fits in well with Norman’s description and also explains that Dunaway’s invention was simply realising that the knot could be used other purposes than just tying on a fly…

Duncan (Uni) Knot Details

The Duncan Knot is named after its inventor Norman Duncan and is also known as the “Grinner Knot”. It was also popularized under the name Uni Knot by Vic Dunaway as a versatile knot which can be adapted to many purposes including snelling; joining two lines; and connecting hooks, swivels and lures with a loop. It is described as being the same as the Hangman’s Noose. Although the two knots are tied differently, the Duncan (Uni) undergoes a transformation as it is tightened. The outer wraps become internal and the resulting knot is the Hangman’s Noose.

for sure, the angling community can be quite grateful for Dunaway’s invention because the basic knot is outstanding and is as good as any other from the reel all the way to the fly (securing backing to the reel spool – backing to fly line – fly line to leader butt – joining leader materials – terminal end to the fly) but adapting the exact same thing, renaming it (even if Uni/Universal really fits the bill) and claiming it is pretty lame so, with the intention of giving credit where credit is due and of sharing a little piece of fishing history, here’s Norman’s story. enjoy !


In the early 1960’s I was trying to develop a new way of tying a nail knot between the fly line and the butt end of the leader, I wanted to eliminate the need for using a nail. Someone had started using a small tube instead of the nail to facilitate the tying of the nail knot which allowed you to start pulling down the knot with the coils of mono tighter than with a nail. Any method of tying a nail knot in a boat was difficult especially if the fish were hitting. Alternatively, I tried tying the nail knot with tension on the fly line so that it would function like a nail. Although it worked it was also difficult since it required three hands and two sets of pliers. Then I started tying an overhand knot with the mono around both the fly line and the mono leader, passing the end of the mono through the loop three to six times then pulling it down with tension on both the mono leader and the fly line. When the mono folded over and started snugging down I then slid the knot down to the end of the fly line and cinched it. This worked alright if you were in a hurry but the mono loops would usually pinch up some of the fly line coating in the process. I then tried the same technique on heavy mono in order to improve my methods. It was when I used these techniques to tie the nail knot back on the mono itself that I realized this created an entirely new knot that could have many different applications. I then started experimenting with different methods of tying this knot finally developing the following as the easiest:

First grasp the end of the line with your lead hand and pull it through the thumb and forefinger of the opposite hand toward then around the base of the little finger to form a loop. Hold the two lines lightly with the same thumb and forefinger pull the end out about 8 inches and circle around to create a 3 inch diameter loop with about 3 inches sticking out. Pass the tag end over the three lines and through the loop at least four times for mono over 100 pound test and successively more times with successively smaller line sizes. Pull the tag end and standing line together snug enough so that the knot will set and not loosen. Then put the loop on something smooth and solid like a small cleat or a gaff hook under foot. Grasp the tag end with pliers and the standing line with the other hand then apply equal tension on both lines in the same direction, pull slowly and hard to control the loop size until the knot folds over its self and snugs up to the desired tightness. The loop size can then be adjusted smaller by putting your pliers loosely against the top of the knot and pull the leader till it slips down. The tag end is cut off by pressing your cutters against the top of the knot between the leader and the tag end at about a 45 degree angle. When cut in this manner, the tag end will make a smooth slope from the leader to the knot and pass through the water without picking up as much grass or debris.

This knot has many possible applications; however it is limited by the low knot strength. In some types or brands of mono the knot strength may be as low as fifty percent depending on how well the knot is tied. If the leader strength is close to the line strength you may want to experiment with the intended application by testing as many of the various sizes, brands and number of turns combinations you expect to use. This can be accomplished by tying the knots then using a line testing machine or just weighing a bucket of water when each different knot combination breaks and recording the results. The best applications that I found for this knot are; it is the easiest knot to tie in very heavy mono, heavy mono or steelon tippet to the fly, loop on fly tippets, mono leader to live bait hooks or trolling lures, the knot can replace metal crimped sleeves.

I invented this knot around 1962 and first started showing it to my friends, then to the various fishing clubs, the sportfishing community in South Florida quickly caught on and started calling it “Duncan’s Loop”. Everyone knew I had invented this unique knot that applied to many of the terminal tackle innovations that were developing during this time period. This name became well established through the years eventually becoming known as the “Duncan Loop”. One day in the mid 1970’s Vic Dunaway the local outdoor writer called me and asked if I could explain and show him my knot, I went over to his house in Cutler Ridge sat on his back porch and explained how I developed the knot, showed him how to properly tie it and demonstrated numerous applications along with the pros and cons of each. I was very surprised when a few months later Vic published an article in a sportfishing magazine in which he claimed to have invented a new knot that he called the “Uni Knot”. I understand that he justifies this by claiming that he adapted the knot to other applications. I have never confronted him regarding what I consider as his stealing and renaming my knot because he acquires notoriety and makes money by publishing articles related to the “Uni-Knot”. Since none of the sportfishing publications have seen fit to publish any of my writings I must find some way to document the innovations that I have made in the sportfishing arena. In this case the outdoor writer published his article about what I had invented over ten years earlier; meanwhile, none of these writers have quoted or published anything that has given me proper credit for the innovations that I created.
Norman Duncan


you’ll find the original article and knot tutorial video published here on TLC by clicking the knot image at the top of the page.

the Tangle-Free Duncan Dropper

tangle-free dropper TLC 6-4-13
i came about this way to rig a dropper quite by accident sometime last summer. it was pretty dark and i was changing the tippet of the main leader and noticed while attaching it to the tippet ring with a Duncan Loop knot shown below (falsely named Uni-knot) that i had poorly judged the amount of tag end (something like 20-25cm / 8-10″…) and for some reason continued, finished and seated the knot. i obviously hadn’t planned adding a dropper and fly but this accident decided for me. in a “what the hell” mood i gave it a try, tied on a nymph and a few casts later caught a fish on that same dropper fly. good beginning.
as we can see, the Duncan’s knot slides along the standing line and seats itself against the hook eye. other than that the knot itself is basically symmetric meaning, in my eye, and after subsequent tests that that compared to a lot of other knots it’s equally strong whether it’s pulled in one direction or the other.
now, the funny thing is that this knot was originally intended to be a loop knot to allow the fly to move freely (read ‘falsely named Uni’ link above) but it easily slides towards the hook eye with a good pull or a good fish but it doesn’t readily slide backwards when pulling on the tag end. interesting.


sure, there are other ways of making droppers and this is just another option. with tippet rings one can just tie the dropper leg to the side of the ring similar to a Pater Noster the bait freaks use . without rings they can also be made by using a long tag end of a Blood knot or double/triple Surgeon’s knot. (i don’t use Surgeon’s because they seat overlapped and crooked. i know very well that it’s a very good, strong and reliable knot but i can’t stand the crooked presentation nor its messy ugliness… )
another method is to tie the dropper from the bend of the preceding fly’s hook bend and the whole rig stays in line. some call it New Zealand style. it’s a great method and nothing could be simpler but it can, depending on the upper fly and how it’s intended to ‘swim’, impede it’s action.

now, the tangle-free part. apart from the ‘off the bend’ or horrid Surgeon’s knot, they all tangle like crazy while casting, specially when casting mid to long range where we tend to false cast more and that’s a shame as it puts off a lot of anglers from using multiple fly rigs (when allowed by local regulations) because it’s a big pain in the ass to constantly untangle and maybe even more so because every drift that had a tangle in the system was a drift that might have put off the fish because the fly(s) where probably going sideways or even backwards all the while having a nest of monofilament mysteriously connected to these awkward imitations, something i’m sure most fish don’t feel too good about.

what’s so cool about the Duncan Dropper is that it rarely tangles if at all.

logic, for lack of a better term, would dictate that a dropper somewhat firmly held at a right angle from the main line would tangle less but it turns out that it’s the other way around. my guess is it has something to do with higher air resistance and the ensuing turbulences created during the casting stroke(s). just a guess that’s not important but what is, having the tag/dropper end come out parallel to the standing line from the knot itself takes away almost all hassles leading to more fun while fishing.
an extra bonus is this method allows us to fish much longer droppers than usual. 50-60 cm are no problems even with bigger flies such as streamers. the longer dropper not only takes the fly away from an online ‘symmetric’ presentation (with the other flies) but since the dropper is longer, the monofilament gives a more fluid/less rigid connection to the main line leaving the dropper fly to move freely thus more lifelike. the extra length of course means not having to redo the dropper after the consequent shortening due to changing flies as much as with shorter lengths.

this dropper does have the limitation of needing to be connected to a ring of some kind but it works equally well on either fly line end loops, monofilament loops (such as a Perfection knot or double/triple Surgeon’s (yuck) and even on furled/braided/poly-leader type leader bodies.
EDITbig D’Oh !!! moment happened later on today when i was out practicing and connecting the red Amnesia line as seen above to another piece. i had forgotten about the Duncan to Duncan knot and using this takes away the limitations mentioned above.
i use the D-to-D to connect mono when joining say, bigger to smaller mono diameters (the Blood knot doesn’t hold well unless the two materials joined are close or similar ex: 4X to 5X is fine but not so good  from  4X to 6X or 7X) and also to connect the finer tippets like 7X and 8X. knot1

i don’t know how i forgot this but there you go, it’s not limited to being attached to some kind of loop or ring. perfect !

as for its strength with a fish on, it’s not like we normally target the bigger, stronger species using dropper rigs but just as an example, a few weeks back i landed a very fit, hard fighting river rainbow trout of 64cm and the knot didn’t move the slightest bit.

to conclude, it’s not like fishing multiple fly rigs are a necessity. they do after all offer a few inconveniences (tangles) say, when landing a hooked fish, multiple hook ups can be a bit stressful to the heart (although fun as hell !) and of course, those who are fond of casting their flies into branches lose two or three flies instead of just one.

thing is, i’m more and more convinced that two or three flies get a fish to commit a lot more than with a single fly and this whether it’s a fish on its own or in groups where these flies might trigger a competitive reaction. something definitely worth trying.

related articles

tuesday night’s challenge

will be to figure out how to tie a Duncan Loop Knot with my tongue and teeth. this should be promising ! :mrgreen:

if you’re into tongue action, here’s the basics. have fun and be sure to let us know how it went.

the Duncan Knot

The DUNCAN LOOP KNOT by Norm Duncan

in this article Duncan explains how he developed the knot and then how it was stolen from him from an outdoor writer and renamed as the Uni-Knot…

“In the early 1960’s I was trying to develop a new way of tying a nail knot, I wanted to eliminate the need for using a nail.

I invented this knot around 1962 and first started showing it to my friends, then to the various fishing clubs, the sportfishing community in South Florida quickly caught on and started calling it “Duncan’s Loop”. Everyone knew I had invented this unique knot that applied to many of the terminal tackle innovations that were developing during this time period. This name became well enough established through the years that it eventually becoming known as the “Duncan Loop”. One day in the mid 1970’s Vic Dunaway the local outdoor writer called me and asked if I could explain and show him my knot, I went over to his house in Cutler Ridge sat on his back porch and explained how I developed the knot, showed him how to properly tie it and gave the pros and cons of the various applications. I was very surprised when a few months later Vic published an article in a sportfishing magazine in which he claimed to have invented a new knot that he called the “Uni Knot”. I understand that he justifies this by claiming that he adapted the knot to other applications. I have never confronted him regarding what I consider as his stealing and renaming my knot because he acquires notoriety and makes money by publishing articles related to the “Uni-Knot”. Since none of the sportfishing publications have seen fit to publish any of my writings I must find some way to document the innovations that I have made in the sportfishing arena. In this case the outdoor writer published his article about what I had invented over ten years earlier; meanwhile, none of these writers have quoted or published anything that has given me proper credit for the innovations that I created.”

-for Norm’s complete article graciously provided for us by Norm himself scroll down to the comments section-

this video shows how easy this knot is to tie, click the image.

keeping the fingers of his right hand inside the loop is a nice trick that’s usually not mentioned. at the end we see him leaving an open loop but we can tighten it down to the eye of the hook as on the diagram at the top of the page if we want. i often use this knot in open loop form at first but it always cinches down to the eye after catching a fish. if a permanent loop is required the ‘Non-Slip Loop’ is a better option in my opinion.

this is my go-to tippet to fly knot. even during tests at home it has not failed once on any sized diameter mono or fly used and even less on a fish. i highly recommend it.


  • Knots (25)  (thelimpcobra.com)