this recent article from Devin Olsen at Tactical Fly Fisher brings up some very interesting points on nymph design, particularly and as the article’s titled-
Wingcases, shelbacks and wings: To invert or not to invert ? that is the question.
among other great observational insights found in the article, one of the most pertinent, easily verifiable by anyone who takes the time to actually look at how a nymph swims when attached to tippet facts is:
– whether the fly is tied on a standard or jig hook, it doesn’t drift horizontally or in other words, its attached by only one end and therefore tilts and it does its thing in a position that has nothing to do with the usual horizontal fly-in-the-vise or fly photo perspective.
– with this in mind another factor worth considering is, due to water turbulence and all the bazillion currents/countercurrents found in flowing water, nymphs and any subsurface fly tumbles, rocks back and forth, spins and twists while they’re swimming and this again destroys the perfect side view described above, once again reminding us that our 2D perspective and subsequent fly designs may indeed catch us fish but we’re probably not seeing a greater picture that might maybe help to make more fish-attractive designs or simply to have a better understanding how our imitations work and finally, if its worth including or subtracting elements to our patterns.
i do like Devin’s conclusion and it definitely fits in with my own experience-
“Last and most importantly, I’ve tried both methods of wingcase placement with inverted flies. Those tied with wing cases in the normal fashion have fished as well or better for me than those tied inverted. Drift theory aside, this is the only real reason that counts much to me.”
this is good stuff so be sure to click either the pic or the link at the top of the page for the complete article. enjoy !