Interlocking loops
Sections of leaders using the permanent leader butt system are connected together with loops rather than knots. 

An "interlocking loop" (or "handshake loop") is done like this:

(for more details on this knot & its use, see Slip On Leaders)

Fly line loops
Some flyfishers use an adaptation of the permanent butt system by employing a "fly line loop" in the end of the fly line.  Some manufacturers sell lines with such a loop.  Or, they can be easily created on any fly line.

This is simply a small loop formed by "doubling back" the tip of the fly line upon itself & securing it in a small loop.   Leaders are then attached from there using interlocking loops.

We do not prefer this method, because the connection is not as strong as other systems, and it creates a bulge in the end of the fly line which interferes with smooth line movement through the guides.

Permanent Butt Sections

"Permanent leader butt sections" are a length of monofilament, of level diameter, or of braided, tapered material, that is permanently affixed to the fly line tip.  It remains attached to the fly line and serves as the butt section for ALL leaders used with that fly line.

It has a loop in the end to which a variety of leader sections may be interchangeably attached using interlocking ('handshake") loops.  We suggest this system for beginning fly fishers, as it makes it easier for them to change leaders.  Regardless of experience level, it is a technique about which all fly fishers should be knowledgeable.

What Are Permanent Butts For?

Permanent butts (or, "line-to-leader loops") are an option that many fly fishers prefer, primarily as a timesaving device.  They are simply an extension of the fly line that saves time when changing leaders. Generally, they are adopted by fly fishers who have been fishing for quite awhile and who fish frequently. We recommend them as practical for rod/fly lines of #6 weight to #9 weight.

The rationale for this adaptation is due to the fact that leaders in the 3 standard lengths, 7 1/2', 9' & 12', regardless of the tippet size/diameter, generally have butt segments that begin with the same diameter:

• 7 1/2' leaders generally start with .019" diameter material
• 9' & 12' leaders both usually start with .021" diameter material

This being the case, in order to save time by not having to tie various leaders to the fly line (with a "Nail Knot" or substitute), this "one size fits all" butt enables us to quickly connect/disconnect all the various leader sections we wish.  If we need a 4X leader, we simply loop it on to the butt section; need a 2X section for a bigger fly? Unloop the 4X, loop on the 2X.  No knots, no trimming, no leader spools, etc.  Quite a time-saver!

How To Create Permanent Leader Butt Sections

There are 3 ways to begin using "permanent leader butts":

1. Tie on the monofilament section to the fly line yourself:
   (a)  to keep things simple, we use a 12" (1 foot) section of monofilament
   (c)  affix this section to the fly line tip using a "Nail Knot"
   (d)  then tie a 1/4" diameter loop in the end using the "perfection loop knot" ( )
   
2. or, buy a "Braided slip-on Leader Butt":
   see the separate description on "Leader Butts"
   
3. or, buy a fly line with a built-in butt section with loop connector:
   Several fly line manufacturers are now providing some of their fly lines with butt sections &/or connector loops.  See sidebar.

A Word Of Caution

One thing to keep in mind with this system, is that if you opt to use the "running start" provided by the 12" of permanent butt section attached to your fly line, any leader segments you wish to connect to it need to be matched accordingly; e.g., you may need to cut off the first 12" of a "store bought" leader's butt in order to balance with your permanent butt section on the fly line. Use of the short butts (5'' or so in length) are not a concern and regular, full length leaders may be attached.

Similarly, leaders you tie yourself should take into account this section; i.e., you will likely not use the first segment in any leader construction as it is already on your fly line.  Also, each leader section you wish to attach to the permanent butt needs a loop in the end.