The short answers –

NOT MUCH, and

MORE OFTEN THAN YOU THINK.

But the long answers are much more interesting, and hopefully quite useful to you as an angler, so here goes nothing.

It starts out with a history lesson, of course.  Once upon a time, long, long ago, the physical weight of virtually all manufactured fly lines was done according to something called the AFTMA (American Fishing Tackle Manufacturers Association) Standard or the AFFTA (American Fly Fishing Trade Association) Standard.  Those standards were developed around 1959, to ideally bring some standardization to an industry which had, according to accounts I’ve read, run rampant for a while, creating confusion among anglers and manufacturers alike.  The idea was that the physical weight of the first 30 feet of a fly line (excluding level tip) would conform to an industry standard for the given line rating.  For example, this would make all 6-weight fly lines, in theory, more or less the same weight for the first 30 feet.  In a perfect world, this system would also serve to bring some standardization to the labeling of fly rods, making rod/line pairings (more on this later) easier.  As far as fly line taper, head length, and overall head weight, though, all bets were off.  But in the early days of synthetic fly lines, double taper lines were king, and our modern complex tapers were barely a dream, so it didn’t matter much.

The AFFTA Standard for single hand fly lines (not Spey lines or shooting heads) remains the same to this day.  Here is the table.  If you are like me, you’ll want to print one of these out for your wallet or save the image in your smartphone.  You’ll see why in a minute.

Where are we now?

The standards were developed in the late 1950s.  I didn’t come around to fly fishing until the early 1980s, and didn’t really get into the nitty gritty until the 1990s.  So, for some of this history I’m relying on second and third hand accounts.  An engineer by training, my brain desperately hopes that the industry strictly followed the standards, at least for a while.  One thing I do know for sure is that line manufacturers no longer follow that standard in most cases.  It is actually rather challenging to find a modern fly line that conforms to AFFTA Standards.  And, if you are like me, who typically really likes how rods cast when lined at or near the AFFTA Standard, just buying a fly line based on a product description and a numerical line rating on the box NO LONGER WORKS MOST OF THE TIME!

What the… ? 

When is a 6wt line really an 8wt?

I do a lot of research on fly lines, both for myself, my friends, and for Big Sky Anglers.  As a result, I’ve been exposed to a wide variety of fly line designs – tapers, 30-feet weights, total head weights, head lengths, cores, and coatings vary WIDELY from line to line and brand to brand.  I love taper diagrams, tables, and spreadsheets that might give me a hint about how a line will cast when paired with a given rod for a specific fishing approach.  The more research I do, the more variations from the standard I find.  Even for someone who likes this stuff, it can be downright confusing.  For most folks that I know who just want to get a smooth casting outfit that is fun to fish with, it’s just black magic.

Why doesn’t the industry follow the industry standard?  It’s a good question.  There are more than a few answers that I’ve heard.  One or more of them may be the reason for the divergence.  Or not.  It’s basically a game of finger pointing.  Some say that modern, super-fast action graphite fly rods have become so stiff that a rod rated as a 6wt, really casts and flexes more like a 7wt or 8wt, despite its super light feel in hand.  And, as a result, line manufacturers have altered their numbering just so that their 6wt line feels right on that aforementioned 6wt rod (even though it’s really a mislabeled 8wt rod).  Many in this camp would like to see a full revision of the AFFTA Standards that conforms more with our modern fast action graphite rods that it did to historical fiberglass and cane rods with slower actions that were the norm at the time the original standards were developed.  Others blame casting ability, and the common desire for instant gratification without effort.   Those pundits say that poor casting ability among the masses has forced line manufacturers to create heavier and heavier fly lines so that those without the skills needed to properly load a fly rod at typical casting distances can actually FEEL something and get a cast out past the end of the driftboat oars.

The thing is, the reason for the departure from the standards isn’t important when it comes to picking the right line for you.  Fly line and fly rod manufacturers aren’t all of a sudden going to change how they label things just because there are guys like me that wish they would.  And there are still plenty of folks who own and enjoy fishing with glass, cane, and fuller flexing graphite rods.  So, what is most important is that you, as an angling consumer, are informed about this topic well enough to be able to make the right choices when it comes to your next big $ fly line purchase.  At a baseline, you should be informed enough to be able to ASK THE RIGHT QUESTIONS when you are talking to an employee at a fly shop or a line manufacturer.

What are some things you need to know in order to get this right?

First, the good news is that modern graphite rods are typically designed with a progressive flex pattern, and are able to accommodate a variety of line weights both above and below their labeled rating, assuming the caster has a reasonable level of skill.  So perfection is not required to achieve functionality.  The bad news is that your rod might not FEEL as sweet as you want it to without the right line on it.

In the past, there was always a lot of talk about up-lining stiff rods to get more flex and feel out of them.  In many cases with modern lines, the manufacturers have essentially done that for you by creating a line labeled as a 6wt that meets the AFFTA standards for a 7 or even an 8wt rod.  Be aware of this trend, because if you were used to up-lining in the past based on the AFFTA standard, and do that with a modern line that is already up-lined at the factory, you may end up with something way heavier than you wanted.

When you decide to buy a new fly line, at baseline you should go to your local fly shop and talk with the in-house fly line nerd armed with an understanding of:

  1. What fly rod you own, and what the rod’s action is (fast/stiff, medium-fast, medium, slow). If you aren’t sure, bring it to the shop.  If you are sure, also bring it to the shop!
  2. What type of fishing you do, and at what distances. If you are a small water angler, nympher, long distance dry fly guy, lake specialist, streamer junkie, etc it will influence the line you choose.
  3. Your casting ability level, currently, including power application, tracking, typical amount of line you like to carry in the air when casting, etc. Be honest with yourself.
  4. Your goals for improving your casting ability. Everyone can get better.
  5. How you like to achieve distance. Do you like to shoot line for distance or carry more line in the air and shoot less for distance?

You should also go into the fly shop ready to ask some questions about the fly line that they might suggest for you.  Fly line manufacturer websites can also be a good source of this information.  At baseline, for weight forward fly lines, be prepared to ask:

  1. What is the head length of the fly line?
  2. How much does the first 30 feet of the head weigh (aka, the 30-feet weight)? And, how does that relate to the AFFTA Standard for that line weight.
  3. How much does the total head weigh, assuming it is longer than 30 feet?
  4. How does the fly line taper relate to my preferred fishing style and skill level? This is another can-of-worms topic that may need its own blog post.  Just remember, even if the manufacturer names a line something like “salmon and steelhead” or “indicator”, it doesn’t mean those lines are necessarily bad for the fishing you do which doesn’t involve those things.  Go at it with an open mind.
  5. Do you have any demo lines that we could cast on my rod out in the parking lot? This is the consumer’s ace in the hole.  If you can cast a line before you buy, DO IT.  Understand, however, that it is impossible for a shop to have demos of every line they carry on the shelves.

Without going down the rabbit hole of fly line taper design, if you can answer basic questions about your rod and your casting (the first list), and can get the answers to the questions about fly line choices (the second list) from your local fly shop, the line manufacturers website, or from the CIA, then you are ready to make an informed decision.  I would recommend following these general guidelines to start, and remember, if you can cast the line on your rod before you buy it, DO IT, and do it with a fly on leader rig that you intend to fish.

This is your brain on AFFTA Standards

When to Consider a Line “Way Heavier” than the AFFTA Standard

By “Way Heavier” I mean something like a 30-feet weight equivalent to 1.5 or 2 line sizes above the AFFTA Standard.   Consider a line of this type when you are:

  • a beginner level caster, and own a fast/stiff action rod
  • a caster who needs or likes to feel a lot of rod loading in order to cast your best, and own a fast/stiff action rod
  • an intermediate or advanced level caster, own a fast/stiff action or medium fast action rod, and fish almost exclusively at very close range
  • any level caster, and like to load the rod very quickly with minimal line out of the rod tip, and shoot to achieve distance (As a side note, using a short, 30-feet long head flyline the equivalent to 2 lines sizes heavier than the AFFTA standard is essentially the definition of a “shooting head”). You will sacrifice the ability to carry longer amounts of line in the air as a result of this choice.

When to Consider a Line “A Bit Heavier” than the AFFTA Standard

Here, by “A Bit Heavier” I mean something like a 30-feet weight equivalent to 0.5 to 1 size above the AFFTA Standard.  Consider a line of this type when you:

  • a beginner level caster, and own a medium or medium-fast action rod
  • a caster who needs or likes to feel a lot of rod loading in order to cast your best, and own a medium or medium-fast action rod
  • an intermediate level caster, and own a fast/stiff action rod
  • a caster who needs or likes to feel some clear rod loading on shorter casts in order to cast your best, and own a fast/stiff action rod
  • an angler who primarily fishes at close to medium ranges (say 45 feet or less)
  • an angler who is happy with carrying a medium amount of line in the air and shooting for extra distance when it is called for.

When to Consider a Line Weighing Similar to the AFFTA Standard

Here, by “Similar to” I mean something like a 30-feet weight within the AFFTA Acceptable Weight Range in the table above.  Consider a line of this type when you:

  • a beginner level caster, and own a slow action rod
  • a caster who needs or likes to feel a lot of rod loading in order to cast your best, and own a slow action rod
  • an intermediate level caster, and own a medium action rod
  • a caster who needs or likes to feel some clear rod loading on shorter casts in order to cast your best, and own a medium action rod
  • an advanced level caster, and own a fast/stiff action rod
  • a caster who is ok with feeling minimal rod loading on short range casts and can still cast your best, and own a fast or medium-fast action rod
  • an angler who regularly fishes at medium to longer ranges (say 45 feet or more) and is capable of adjusting power application for shorter casts to still achieve good results
  • an angler who likes to carry a longer amount of line in the air and shoot less for extra distance, or an angler looking to both carry a long amount of line in the air and shoot significant line for extra distance. (Note that for the latter case the overall head length and fly line taper design you choose will be of utmost importance)

And with that, I believe I have said enough.  I have probably dug myself into a hole that I may never emerge from, and/or guaranteed that I will receive a series of corrective emails and texts from my casting nerd friends.  At the very least, I hope that this saves some of you who are thinking about getting a new fly line some trouble, and that you are able to find the joy that is a properly paired rod/line combination that meets your casting and fishing style.

Take Care and Fish On,  Matt