Introduction

The mechanics (a subset of physics) of fly casting is something I’ve been reading about for a few years now. I’ve also had the pleasure of talking with experts in the field who have generously shared their knowledge and provided guidance. Lastly, an indefensible amount of time has been spent on internet forums, both as a reader and a poster.

Overall the online experience has been interesting – as they say – informative sometimes, frustrating often and seriously helpful occasionally. Everyone seems to come to this subject matter with their own perspective, wishes and attendant expectations. When they encounter a different perspective it doesn’t always end happily. This probably helps explain why there is a lot of argument online about casting in general and the physics of it in particular. Arguments don’t interest me much.

So, it is best to declare my perspective on all this stuff. I am a fly fisher and not a physicist and have no interest in becoming a (fly fishing) physicist. Fly casting interests me because I enjoy doing it better and because that in turn improves my fishing. Understanding the physics involved fortifies and clarifies my understanding of fly casting. It provides a filter for letting in helpful stuff and for screening out some of the BS. It is a testing board for what seems to be going right and/or wrong with my casting, helping me to accentuate the good and eliminate the bad.

The majority of fly fishers probably aren’t too interested in learning to cast better. Fair enough. Only a small percentage, let’s say 5%, are interested in what light physics might shine on their casting. When our hopeful five percenters go in search of enlightenment they often encounter posters who know something about physics and who like to fly fish. These folks frequently want to talk about fly casting in the context of physics instead of physics in the context of fly casting. Knowing something about physics gives them authority and status. Knowing something about fly casting not so much. This sets the scene for problems, argument and the five percenters not getting much of what they went looking for.

Am I different? Yes. Am I the guru? No. Have you at last found nirvana? Probably not. What you have found is a guy who can mostly get his head around the relevant physics well enough to write stories about it for fly casters who are interested in reading them. Yep, you’re right, it’s not likely to go viral!

What’s it got to do with Einstein? Well, Albert was very smart and much admired. Consequently, people have attributed and misattributed quotes to him. One of the popular misquotes is that, “If you can’t explain it to a six year old, you really don’t understand it yourself.” He didn’t say that but it’s a nice idea. Taking up the spirit rather than the letter of it, my aim is to explain this stuff simply enough so that it can be understood by an intelligent sixteen year old who wants to cast better. Please don’t get hung up on the age level. The point is rather that my challenge is to explain complicated things simply, thereby improving the odds of us both understanding it. 

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