Good morning class. I’m Professor Mike, an adjunct instructor here at Fly Fishing University (FU), and today we will begin a series of lectures on the baffling mathematics of our chosen sport.
While it doesn’t take a rocket scientist to be a fly fisherman, an advanced degree in math certainly doesn’t hurt. The numerology imposed upon us is confusing, at best, and often downright diabolical. This lecture series is designed to help you sort your way through the math maze so that you might become a more knowledgeable angler. Upon completion, you still may not be able to catch a damn thing, but you should be able to talk a good game – which is, after all, the basis for a successful career in fly fishing.
In today’s lecture, we will begin with the fly line.
There are many who believe that this curriculum should actually begin with the fly rod because it is widely held that fishermen, at least the male contingent, think about, and with, their rods first. We will carefully avoid that discussion here, but if you’re interested in further studies, it’s fully covered in Fly Fishing Biology 101.
As I was saying, we will begin with the fly line as it is what truly separates our sport from the barbarian wasteland that is common fishing. In most of the fishing world, casting is accomplished by throwing weighty lures, or bait, into the water. The weight of these items allows lengthy tosses and the line is simply a way to stay connected to the deceit. In fly fishing, our temptations are typically concoctions of feathers and string that we couldn’t throw two feet without a good wind at our backs. The line, then, provides the propelling mass.
Before the early 60s, lines came in three sizes – a sliding scale of too small, just right, and too big. Simple. So simple, in fact, that the fly fishing industry needed to do something about it and instituted the weight, or wt, numerical convention. As implied by the term weight, the system loosely correlates line designation, a numerical scale from 1-to-14, to how heavy the line is.
The move was genius. What self respecting gearhead fly fisherman would be satisfied with just three lines – one each too small, just right, too large – when he could have fourteen? Fly shop cash registers around the world chimed in unison.
But what, exactly, is a weight? What, for example, does having a 5wt line really mean? Lets look closer.
The weight of a line is determined by how heavy the first thirty feet, or head, of the line is. In ounces, you ask? That would be too easy. The industry chose grains. Leave it to fly fishing to define one nonsensical unit of measure by employing a second. At least it's not metric.
There is one theory of the measurement’s origination that points to the odd coincidence that our pharmaceuticals are also often designated in grains. It was, after all, the early 60s and you know fly fishermen. To delve into that further, feel free to check out Fly Fishing Deviant Psychology 302 here at good ol’e FU.
But let’s get back to the details.
The head of a 1wt weighs 60 grains, give or take some non-standard margin of error. A 2wt weighs 80 grains, 3wt 100, and so on in 20-to-40 grain increments as we move up the scale, arriving at a 14wt of 455 grains. 1wt-to-14wt, equivalent to kite string-to-telephone cable.
It should be noted that, to its credit, when designing the weight system, the industry had the good sense to associate the smallest standard line as a 1wt and then have the lines get heavier as the designation increased – a convention they would not adhere to very well, as we will see in future lectures. Assholes.
So the first 30 feet of a 5wt line weighs 140 grains. Great. But what does that mean to the fisherman? Well, unless you are into the hard physics of things, not much. Yes, you could begin hashing through the calculations of a particular line’s weight, it’s kinetic effect on flies of varying masses and wind resistance and begin factoring interactions with the fluid dynamics of atmosphere and bodies of water, but that’s graduate level stuff here at FU, so don’t worry about it just now. Just use the following scale to determine line weight – where to use – what to catch.
1wt – The kid’s fishbowl – goldfish, guppies, clown loaches
2wt – Tiny trout streams – rhododendrons, ticks
3wt – Farm ponds – bluegill, sunfish
4wt – Medium trout streams – rainbows, browns, brookies
5wt – Classic trout streams - skunks
6wt – Big trout streams and rivers – bigger, more expensive skunks
7wt – Does anyone actually own a 7wt?
8wt – Bass water - smallmouths, largemouths, loudmouths
9wt – Saltwater – stripers, redfish, bluefish, seasickness
10wt – Saltier water – False Albacore, Mahi Mahi, Mai Tais
11-14wt – Are you kidding me?
Easy, right? Well, wait a minute. Weight isn’t the whole story. There’s also a whole series of sinking lines that do not use the wt numbering system at all. Instead, they are sold using their straight grain weight and/or a designation of how fast they sink, measured in feet/second. They may also be designated by Class, an additional layer of abstraction, exacerbated by the odd convention of using roman numerals – e.g. Class IV sinking. It all gets very confusing and we will blithely ignore them at this point in time. Unless you’re a masochistic striper or stealhead fisherman it’s merely academic anyway. Besides, it’s more FU graduate level stuff – Fly Fishing Chuck and Duck 501.
Well, that’s it for today. I hope that this class has been enlightening and that, by understanding the fly line and it’s numerology, you have taken your first steps towards deciphering the code of fly fishing mathematics.
See you next class when we will examine our rods.
Please stop snickering.