The Fly Line Guide

The Fly Line Guide (Nick Hart)

The Fly Line Guide

Compared to the satisfaction experienced when purchasing a new rod or reel (Fin & Fly February 2011 & March 2011) the fly line may seem a little more mundane. But I urge you to become very excited about this important item of tackle which is widely regarded amongst many fly fishing instructors (check out the Hardy & Greys Academy) as the key to successful casting... coupled with good technique of course!

What is a Fly Line?

The short answer to this question is that our plastic fly line acts as a weight designed to propel virtually weightless leaders and flies to a selected target. Simple enough but pick the wrong weight for the job and casting will become a frustrating chore! The information following represents a basic guide to choosing a suitable line.

Feathers or Rocks?

There are a number of important factors to consider when selecting a fly line based around our chosen venue, size of fly required to capture the target species and weather conditions. To facilitate the process each line is classified by a number representing its weight, a system designed by the Association of Fishing Tackle Manufacturers and otherwise known as AFTM. The same system is also applied to fly rods to denote the line weight which they have been designed to cast. The acronym is not important and neither is the method used to calculate the weight, instead think of fly lines as feathers, pebbles and rocks!

Line weight #0 to #5 - These lines are the feathers, generally designed for short casting and very gentle presentation of gossamer leaders on small streams/brooks. #0 through to #3 is fairly specialist, aimed at anglers searching for ultra lightweight sport coupled with rods such as the new Greys XF2 Streamflex range. Casting in windy conditions with such light lines would be difficult and these featherweights are not suitable for large fly patterns. Select a #4 to tackle most small stream Trout fishing with ease and a #5 for medium to large rivers.

Line weight #6 to #9 -These are the pebbles which allow us to cope with blustery conditions (coupled with good casting technique!) presenting medium to large flies at a considerable distance if required. #6 is a very popular line with small stillwater anglers although #7 is regarded as a more all round weight. The #7 is a medium heavy line (think of it as a medium sized pebble) that is light enough for small water work, even in flat calm conditions but also suitable for casting a reasonably large lure on a windswept reservoir. Extreme circumstances may even call for #8 or #9, although these would be regarded as very heavy still water line weights more often selected by saltwater anglers casting large flies such as the Clouser Minnow to Bass or heading to the tropics in search of Bonefish.

The Fly Line Guide

Line weight # 10 and above - Lines above #10 should be thought of as rocks where gentle presentation is not a cause for concern. Salmon for example generally inhabit fast flowing rivers and will not notice the heavy fly line landing upon the surface of the water therefore making it an ideal selection for casting with double handed rods such as the Hardy Demon. These heavyweights will also cope with a windy climate enabling the turnover of very large flies prompting fly fishers to diversify into a range of exciting species including Tarpon and even Sharks; just add a Hardy SINTRIX Proaxis!

The information above represents a very basic approach to fly line selection and a few generalisations. For example some anglers target Bonefish with #6 lines and a New Zealand river may require an AFTM 7 or 8 approach. The key to success is thoroughly researching your chosen venue prior to arrival and selecting a fly line weight based on the information available. As a general rule of thumb don't go lighter until you have experience!


Fly Line Tapers

Fly Line Tapers

The taper of a fly line may seem like a bewildering subject, especially to newcomers, however once again the AFTM system has produced a simple code to facilitate choosing the right product. For example the traditional double tapers, coded DT, were frequently used by river anglers in lightweight sizes for Trout (e.g. DT4) and heavyweight for Salmon (e.g. DT10). DT lines are of an equal diameter throughout much of their length (described as the belly); accept for either end which features a taper. The DT profile design enables excellent loop turn over but in recent years they have fallen from favour and been widely replaced by the weight forward (WF) profile.

Weight Forwards (WF) feature a tapered tip and wide diameter belly that is used to load the rod while casting. Following a rear taper the belly narrows to a low diameter section known as the "running line" which forms much of the WF profiles length. The idea behind a WF is simple, load up the rod with the belly and the thin running line will shoot through the rings with ease. An ideal choice for still and saltwater fly fishers! In fact many river anglers use WF lines too because the front section is very similar to the DT profile, providing the same benefits of a double taper at short range but with the ability to make longer casts if required.

Once again this information should only be used as a general guide because fly lines tapers and profiles are constantly evolving. By altering the belly length (also known as the head), rear taper and running line all manner of results can be achieved from ultra lightweight presentation through to mammoth distance. If all you need is a standard WF profile then the Hardy Premium range is difficult to beat while more experienced casters will enjoy the increased head length and ultra thin running line of the Hardy Mach 2. The Mach concept has also been rolled out into specialist Spey Casting products with a choice of 55 or 65 foot heads.

Core & Coating

If profile design has received a great deal of technical attention then it is fair to say that the core and coating has also been under a reasonable amount of scrutiny. Poor quality fly lines may suffer from a rough or "tacky" coating, while coiling known as memory, is a serious problem. Both factors will impede the lines ability to shoot through the rod rings efficiently and are often present within budget priced fly lines. It may seem like a good idea to throw our entire budget at a decent rod but it is absolutely essential to allow enough for a high quality fly line. The Greys Platinum XD Fly Line is a joy to cast with an ultra slick coating and supple core which at £44.99 represents great value across a couple of seasons fishing.
An excellent freshwater choice but beware, don't take this line to a hot tropical climate fishing in saltwater! The high temperatures can quite literally melt a fly line that has not been designed for purpose. Instead opt for a specialist product such as the Hardy Mach Saltwater which features a stiff coating/core suitable for tropical fishing conditions and a profile designed to turnover large heavy flies.

The Fly Line Guide


Coarse and Sea anglers use floats and/or weights to control the depth at which they present a bait; fly fishers use a fly line. Coded as a letter by AFTM a floating fly line is simply F, so as an example a weight forward number seven floating line would be shortened to WF7F, look on the side of the fly line box for this information.

Mid water fishing can be achieved using an Intermediate which is essentially a very slow sinking fly line, followed by medium sinkers and fast sinkers. Many modern products include a guide to the sink rate which enables us to estimate the depth at which we are fishing by counting as the line descends.

River anglers will probably need little more than a floating line for most stream fishing situations while a Reservoir boat angler could eventually own multiple densities to cover a variety of depths and climatic conditions.


This is very much a personal choice. For example some river anglers like the benefits of a brightly coloured floating fly line as they feel it helps them to see subtle takes while others opt for a sombre shade, convinced that their quarry will be frightened by a fluorescent day glow number!

Intermediates which sink slowly can be found in various light green and blue shades although the clear "slime line" varieties such as Hardy's excellent Mach 2 have become very popular.

Full sinking lines are usually Brown, Dark Green or even Black and designed to blend in with their background when fished deep.

Two tone lines have revolutionised the weight forward profile by denoting the belly/head section as one colour and the running line as another. This can be particularly useful for beginners when learning how to cast and more experienced anglers searching for the optimum loading point of a rod. See the Hardy & Greys range for a number of products featuring this two tone technology.

The Fly Line Guide


As this guide reveals there is more to choosing a fly line than one might expect and a high quality product could well be the difference between joyous casting or yet another frustrating session. In fact it is fair to say that a brilliant rod coupled with a poor fly line can be a horrible match! So when choosing a fly line think about the venue you will be fishing, the conditions you may encounter and the flies that you will be casting. Pair line with a suitable rod designed to cast the required weight and buy the best that you can afford, keeping in mind that the AFTM code has been created to facilitate the process.

Readers in the UK can buy products mentioned in this article direct from Hardy - click here for more.

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