The Nail Knot remains a popular knot with fly fishers for attaching the leader butt section to the fly line.
Many fly lines these days are produced with welded loops, but some fly fishermen feel the energy transfer to the leader butt – all important in getting it to roll over – is better with the nail knot connection than a loop to loop connection.
It is not the easiest fishing knot to tie, but with a bit of practice using these instructions below you’ll quickly be able to tie it in a few minutes in most fishing conditions. (To make things even easier you can check out some of those nail knot tying tools.)
As the name suggests, the Nail Knot does require a nail, or equivalent long thin object, to tie. Or even better, use a purpose built nail knot tool [link].
One of the key reasons to use the nail knot is it is a tight, compact low-profile knot that will slide through the guides on your fly rod, particularly if coated in a pliable glue like PlioBond.