Fly line tensions .... "stretchy vs. non-stretchy lines"

The other night I had a very interesting discussion with a good freind of mine (who is an exceptional caster) about the efficiency of a cast while casting for distance.. The main part of the discussion was line stretch in long casts especially with say a weighted fly on the end.. What sparked the conversation was when we were taking the twist out of a badly twisted line that I had.. When we stretched the line out between us you could easily stretch a extra six inches to foot in the line with minimal pull. How much if at all do you think the "stretching" in a line while casting takes away from the energy/efficiency of the cast and how much distance is lost in the cast.. Also could this be corrected if a line was designed in such a was as to not stretch???

This was a hot topic during 2002. In the Fall issue of THE LOOP, Mel Krieger posed the question: "How Does Line Stretch Affect the Cast ?" That was the title of his article.

This was re-visited in the in the Winter 2002 loop. Responders who answered the burning question included such experts as Bruce Richards and Tim Rajeff.

For details, go ahead and access these LOOP articles from the FFF website or: http://www.fedflyfishers.org/loop.php I strongly recommend you do that to get the benefit of a lot more information on the subject.

In a nutshell, Bruce points out that, "Line stretch during casting is not our friend." He went on to say that when he designed lines for distance casting back in the 70's that lots of stretch caused big casting problems. He described badly distorted loops and the fact that after the rod had stopped and the loop formed, that tension was released and the line, "relaxed" and, "accordioned". This resulted in a series of S curves in the fly leg which were wind resistant. Distance suffered. They solved the problem by changing the cores to those with less stretch. He pointed out that while energy can and is stored in a stretched fly line, that its release is not well controlled .... a major problem.

He pointed out some advantages to having some stretch in the line, and ended with a recommendation to tailor the stretchability of the fly line to the use for which it is intended.

Tim Rajeff's reply began with this: "The perfect casting line would be as skinny as possible, very flexible (soft, with no memory) and have no stretch." He went on to say that the stretchy lines didn't cast as far as other lines in use because they proved to be unstable in stretching out so much during the final delivery cast. He called this the, "rubber band effect".

His conclusion: "So the less stretch your line has, the more stable the loop is in the air and the farther your cast will go (all other things being equal)".

They also noted that when competition accuracy casting, that the different stretchability of fly lines was most obvious .... it provided another variability to consider.

2.) Lines with NO STRETCH, such as the lines with Dacron cores and, especially, those made with Kevlar and Spectra cores casted well. The distinct disadvantage of these lines was the fact that once they took a, "set" while wound on the reel, we could not get the curls out. If a sneaker rolled the line, a kink formed .... same if a knot in the fly line had to be unknotted..... it was impossible to get the kinks and curls out.

3.) Back in the 70's, we tested the highly touted, "SUE BURGESS" fly lines which were being produced in England by the former Airflo Company. They had cores of 18 lb. test Kevlar (Aramid.... Du Pont). ..... Zero stretch. We noted the disadvantages described, above. They casted well. Then we discovered that after a great deal of casting, we'd make a distance cast .... and the fly line would break in two in mid air while under casting tension and the distal section would go out to the next county. The Kevlar became brittle !!!!!! They never broke while fighting a fish .... always in mid air during the cast. (??????)

4.) The lines made over gel-spun cores had another disadvantage: When we fastened the butt section of the leader to the end of the line with a nail knot, the knot would often pull the coating off the core as a fish was fought. When we went to using an Albright Special, the coating stayed on, but fractured just above the knot which led to a less than ideal transfer of energy over the, "dead spot" which that produced. Same thing happened (though later) when we went to loop connections.

5.) Super supple / stretchy lines can sag between the guides on the fly rod. This is a minor reason added to the above which make them less desirable for distance casting.

6.) We found that the soft / stretchable lines would tangle more easily. While the tangles were easy to undo and left no kinks, that didn't help a bit when a, "bird's nest" of a line mess caught in the guides as we cast to the only tarpon of the day !

# Check out the information on fly line cores in Bruce Richards' MODERN FLY LINES. In this book, Bruce points out that these differences in fly line stretchability are far less important for most casters making fishing casts than for competition distance casters where the fly line tensions are much less. That helps bring us back to the real world of fly fishing.