Research on sink-rates of Nymphs

By Rene Vaz, based on research and findings from Kiyoshi Nakagawa via Manic Tackle Project

“Yoshi had always found that many of the concepts and beliefs he had been taught as a fly fisher were based primarily on assumption”

sounds familiar, huh ? here’s a most excellent article, a real eye-opener for any angler who fishes sub-surface weighted flies.

“along with the assistance of his original professors have began to conduct a number of physical experiments on the performance of fly design on sink rates in varying environmental conditions. Current research project focuses around the sink rates of trout flies tied from different materials.”

Copy of Lead and Tungsten 1.xls“Furthermore the graph shows that there is little difference between the two flies of 0.6 or 0.8 grams in either tungsten or lead. And in fact, the major differences that occur are only due to the density of materials versus the overall weight. Interestingly enough this becomes a critical piece of information for anglers wanting to tie fast sinking nymphs whereby traditionally anglers have fished larger and heavier flies in order to get to the bottom quickly. This research however shows that small high density flies will in fact sink faster than larger and heavier patterns. As we can see above, the 0.6gram Tungsten nymphs sink more than twice as fast as the 0.8gram brass nymphs”

and that’s just an appetizer. click the graph to access the main course. bon appétit !

2 thoughts on “Research on sink-rates of Nymphs

  1. That’s exactly what I have been saying for years. It isn’t weight that causes a fly to sink, its density. The other materials on the fly affect sink rate hugely. You could float a hook with a tungsten bead if you add enough light weight materials.

    • hi Alan,
      sure, but it’s also about fly profile and the hydrodynamic properties of the fly. the ‘Perdigone’ style is a fine example of lighter weight nymphs that sink incredibly fast.
      thanks for stopping by !

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