Capt. Mel's Tube Knot

Published Jan 16th 2012

A Fly Line to Butt Section Connection


Things you need and the finished knot

About 5 years ago after seeing so many really bad knots connecting the fly line to the butt leader section, I came up with a knot that did not break, was a permanent part of the fly line and will easily go through the guides if necessary. I don't use anything under a 6 weight but I don't see why it won't work for all line sizes. It is not an easy knot to tie but when I'm pulling on a tarpon that's over 150 pounds I can feel secure that at least that knot wont break or come apart. I hope you can understand the step by step process of how to tie this knot from the following pictures and my explanations. I used a 13 weight fly line and 50 pound mono for the butt section.

See Captain Mel tie the knot on our video channel.
  1. I use a tube, one as small as possible but will still allow the butt material and the stripped fly line to fit into it at the same time. You may prefer a different method of making a nail knot with some other devise and that will still accommodate both the mono and the stripped fly line back through the nail knot.

  2. To strip the coating from the fly line I used a girth hitch and 20 pound Hard Mason leader material.

  3. Pull the girth hitch up very tight onto the fly line before stripping off 5 '' of the coating. (Yes you lose 5 inches of the fly line but only once.)

  4. Here the coating has been stripped off the fly line, I painted it orange so you can see it in the knot.

  5. Tie a 6 turn nail knot, using the the tag end of the 50 pound mono, around the tube, the fly line and the butt section at the point of where the coating ends. This is a very important point because if you leave any of the coated part of the line beyond the knot it won't pull up tight and will be too bulky. If you allow the stripped part to be inside the knot you may have hinging between the butt section and the fly line.

  6. Once the nail knot is snug around the tube, take 3 turns of the stripped off fly line and wrap it around the butt leader and stick it into the tube.

  7. Remove the tube and very carefully pull the nail knot semi tight, (remember to make sure it stays on the coated part of the fly line!)

  8. At this point you will need some pliers to pull and jam the stripped line up against the nail knot.

  9. With the nail clippers trim the loose ends of the mono and the stripped end as close as possible.

  10. You may use glue to secure the knot but it's really not necessary.

Please, if you have any questions or thoughts about this knot or suggestions on ways that I can do a better job of explaining the tying of it let me know!

Good luck,

User comments
From: Ron Mazzarella · flyfishrm·at·  Link
Submitted March 5th 2013

Capt Mel, great knot! I have been using the nailless nail knot for years and almost forget how to tie one using the tube. I have been looking for a tube that I can use to practice this knot but no one seems to have one. Do you sell tubes for this knot? I use to use an albright on my tarpon lines but it made the knot a little big.

From: Capt. Mel Simpson · melsksig16·at·  Link
Submitted January 17th 2012

Have you tried the double grinner? I'ts very bulky if you don't strip off the fly line coating, and then all most impossible to pull down at the coated and uncoated juncture. If I was going to use the loop system I'd just go with the new molded loop flylines. My concern with a loop to loop system is the leader material cutting through the loop.

From: Neil - Full name and email anonymized  Link
Submitted January 17th 2012

Sort of like a double grinner knot. i find it easier to make my own loops using thread and superglue, then a rubber glue.

From: Mike  Link
Submitted January 16th 2012

Very nice! I will try it!

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