Corrected Duncan Loop:
I am trying to correct some improper illustrations found in many web-sites and several publications that show how to tie a fishing knot that is variously known as a Duncan Loop, Uni-Knot or Grinner.
In Geoff Wilson's “Complete Book of Fishing Knots & Rigs” the illustration of the “Duncan Loop” is shown improperly since the initial loop is formed on the standing line side of the hook eye.
This improper illustration of the Duncan loop is a non-slip loop and to my knowledge has no name, it may or may not have similar breaking strength as the Duncan loop depending on how it is set and what type of fishing line is used.
When the initial loop is formed in the tag end portion of the line after passing through the hook eye it can form a Duncan Loop if properly set.
In the same frame of the book, the illustration immediately below labeled “Uni-Knot” is a proper illustration of the Duncan Loop although the snugging and final setting are not shown. The Uni-Knot is a later renamed copy of the original Duncan Loop.
If pulled down and set properly the final configuration of the Duncan Loop, Uni-Knot or Grinner are all the same.
I believe that some of the confusion lies in the manner of which these knots are pulled down and set after the last wrap with the tag end is passed through the initial loop. In my knot and the Uni the tag end is pulled in the same direction as the standing line with sufficient force to allow the wraps to wind back over themselves to form a neat spiral over the standing and tag lines, like a nail knot tied back over on the line itself. If this is not done the knot will not fold over and therefore form knots that differ in their final configuration and strength.
I can help clarify some of the difficulties encountered when tying this knot in ropes and lines used for boating. Norman