"The Line Article: Fire Hoses, Springs, and Slices of Bread"
By Zach Matthews
December 4, 2004 | Help and Instruction

Beginning fly casters often get a lot of advice on which line is best for them, without ever really understanding the why of it. In fact, in the last couple years manufacturers have recognized the lack of knowledge out there and started labeling their lines by species. This is a good way to pick a line that works but it won’t help you when you try to make a certain line do something it was never intended to do. This article is the layperson’s guide to flylines.

Fly lines come in three stripes: floating, sinking, and shooting. Floating lines are generally made of polyvinyl chloride (PVC) or polyethylene plastics fused to a core of braided Dacron or multifilament material. Basically, they are completely synthetic creations, so they can be shaped however a line maker wants. Floating lines usually contain some kind of near microscopic glass bubbles, which are cooked into the coating and help to trap air. As we all know, a balloon on the water floats, even a long, very skinny one.

Sinking lines are also fused plastic coatings around a synthetic core, however they may be made to sink in a variety of ways. Most have some kind of lead or tungsten or other heavy material cooked into the plastic just like those little glass balloons. Some, like Cortland’s LC-13 product, have a core that is literally made of lead. Manufacturers can adjust just how heavy certain parts of a line are, which you need to keep in mind when we discuss “density compensation” later on.

Shooting heads are short, 25-45 foot long lengths of other types of flyline, from floaters to sinkers, that are attached to a very thin, very long piece of monofilament or specialized “running line.” A lot more on those later.

Now, the rest of this article will be explained in terms of third-grade science project physics, you remember: kinetic and potential energy. If you want to know the actual physics of these processes, contact your friendly neighborhood scientist. My goal is for you to understand how to make flyline do what you want it to.

Fly lines, as I mentioned, are shaped at the manufacturer’s will. The most basic shape is “Level.” This is shaped like a rope- all one thickness and all one material. In the earliest days of flyfishing, and for the less advantaged anglers even today, this was what one got. A better design is called the “Double Taper.” Double Tapered lines get smaller and smaller on each end of the line and maintain a thicker middle. This is a better line for making a soft presentation, as we will discuss when we talk about “energy dissipation” below. The most modern invention is the “Weight Forward” line. Weight Forwards have a lot of their mass up front, in the first 30-60 feet of the line, which allows the angler to carry that “head” in the air and then release it going forward, where its extra bulk helps pull out the thinner running line behind. Sound like familiar terms? You’re right. Weight forward lines are simply less extreme versions of shooting heads. The key difference is weight forward lines are usually all of a piece, while shooting heads are held together with multiple loop to loop connectors to allow you to custom tailor your line to your needs on the fly.

Springs and Levers

When an angler bends a flyrod, he stores potential energy in the blank. The “blank” is the actual long thin part of the rod with all the components and pretty jewelry left out. When that rod unbends itself, it releases that potential energy as kinetic, motion energy. If you went outside and put your rod together and put the butt on the ground and pushed the tip down, then let it go, the rod would jump up in the air, just like a spring. (Please imagine wearing eye protection as you try this.) This is because the rod is a type of spring, because it can store and release energy when it is “loaded” or bent, and “unloaded” or allowed to return to its regular position, straight. In addition to being a spring, the rod is also a lever, because small movements you make at one end of it can turn into much bigger and more powerful movements 9 to 15 feet away at the tip.

Now imagine you have lined up your rod and cleaned the dirt off the butt. You hold onto one end of it, keeping it still, just like when you put the butt on the ground. When you begin to cast, carrying line back and forward in the air, the rod compresses by either bending forward or backwards as the line pulls one way or another, just like when you pushed the rod tip down. This compression stores potential energy in your spring, which is released when the rod returns to a straight position, just as your loop passes by you. Also, because you are moving line around from a point, the tip, that is several feet away, you get all the advantages of your lever. Pretty cool, huh?

The lever and the spring work together to pass that kinetic energy from the rod into the line itself. This is crucial information- just like a spigot can pass water into a hose, so too can your rod give energy to your line.

Fire Hoses and Garden Hoses

Now think about that hose for a minute so we can get back to line design. If you imagine a fire truck hose, it can contain a whole lot more water than a regular garden hose. This is like a heavy, 12 weight line, compared to a light 3 weight line. Now attach your imaginary fire hose to a really weak pump, the kind that can only hold a certain amount of pressure. When your pump tries to fill up a fire hose, the hose lays limp and only a trickle comes out. Attached to the garden hose, you can still get a pretty fine stream. The pump is like a 3 weight rod compared to the spigot, which is like a 12 weight rod. These things have got to match up, you see. But what if you stretched your fire hose a really long way away? Eventually even the spigot wouldn’t be able to make more than a trickle come out. But you still need some water, right? So you attach your thin little garden hose to the end of your big thick fire hose, and although only a trickle was coming out of the fire hose, you still have just enough to fill your garden hose. You have tapered the end of your hose to accommodate the little bit of energy that is left and get the most out of it.

Now the amateur physicists out there will protest that a pump would eventually fill even a fire hose with a bottleneck like that garden hose on one end. That’s true, but keep this in mind as an analogy when we go along anyway.

The tapered hoses are just like the final taper on a double taper (DT) flyline. That “necking down” of the plastic in the line allows the energy your rod throws into the line to be just enough to flip the line over at the end. If you kept the same thickness of line, the fire hose, all the way to the tip of the line, the energy would be reduced to a trickle and the line would go limp and collapse. (This is what often happens with level lines). Only by adding that taper can the last bit of energy be enough to turn over the fly. This has by way of added convenience the advantage of spooking the fish less, since the line makes a nice, soft turnover and hits the water gently.

Slices of Bread

Imagine cutting your favorite fly line into little slices, like bread. (Don’t do it!) If you have one of those cool species-named lines, like ‘WF5F Pickerel,’ you certainly have a weight-forward line on your hands. If you chose a piece from the anywhere on the back of the line, it would be a little bitty slice. If you chose one from the middle, say, 60 feet from the tip, you would notice it beginning to be a bit bigger. If you picked out five slices each a foot apart from that point, you’d see them get bigger and bigger until they leveled off as a big slice for a while. That stepping up from the back of the line is the “rear taper.” The level big part is the “head” – remember, this is where the extra weight on a WF allows the line to pull the thin line behind it, like a plug fisherman throwing a heavy lure. If you moved to the front of the line, you would see littler slices again just like the fire hose turning into the garden hose. This is the front taper and WF lines have them too.

A DT line would have little slices growing bigger toward the middle from either end of the line, then staying fat all the way to the other end. A shooting head line would have a tiny slice all the way to the front 30’, where it would suddenly become a very big slice indeed. On a lot of shooting heads, there is no front taper (because people makes them themselves out of scraps of other lines).

Casting

When one casts a WF line, the energy from the rod still has to move into the line like the pump and the hoses. The problem is, it is hard to move enough water from a small hose, the garden hose, into a big hose, the fire hose, when the garden hose comes first. A weight forward line is just like that. If you are carrying the head, as you should, the slice of bread at the tip of your rod will be one of those littler, back-end slices on the rear taper. In order to transfer energy into the line, you have to get that tip moving pretty fast to “pump” enough energy in to force the heavier, weight forward portion at the head to move. Now we finally get to line design.

A Beginner’s Line like the Scientific Angler’s Headstart has a very short head, only about 40’ or so all the way to the back taper. This allows someone with less than perfect mechanics to push enough energy into the front head to carry it, but only enough to carry a shorter amount (think short fire hose). The SA XXD, a distance tapered-line, is designed for expert casters and has a very long front head (a long fire hose), which will unroll farther if the angler has the skill to carry the line.

Your “Pickerel” line is somewhere in between. The line manufacturers have adjusted the length of the head, as well as the length of the front and back tapers, to accommodate what they see as your kind of fishing. For a “Bass Bug” line, the head is very fat and heavy, somewhat short, and has an abrupt forward taper to suddenly force a lot of energy from the fat part of the line into a very thin part of the line, speeding the tip up at the last minute to give enough oomph to turn over a heavy bug. A “Nymph” taper is a less extreme version of the same principle. A “Trout” line is more likely to be a thinner, lighter head with a long, extended front taper to allow very gentle turnovers of lighter flies. A “Distance” line has a very long head as discussed, as well as a very long rear taper to smoothly move as much energy into the head as possible. That has one other advantage.

Overhang

Shooting heads are similar to distance lines in that they both are attempts to reach a long way away. However, where distance lines do this by stretching a whole lot of line out in front before releasing, shooting heads compress all that weight, which in fly lines is measured in “grains” like bullets, into a shorter, much heavier section. It is not uncommon to “overline” shooting heads by as much as two or three line weights to match a given rod. The thing it takes a lot of anglers a long time to learn is this: a loop of line will only unroll so far, and you need to delay that unrolling for as long a time as possible in order to allow the shooting line time to run out. A delayed turnover equals a longer cast just like a longer hang-time on a football punt allows the kicking team to pin the opponent further back. It isn’t where the ball comes down that matters, it’s the length of time it takes the kick receiver to get hit. If your loops begin to unroll the minute they pass the rod, they will be through unrolling only (with a shooting head) a little over 30’ away from you, and most of the line you shoot is going to end up as slack. If the loop doesn’t begin unrolling until it is 30’ away from you, the shooting line already has a 30’ advantage and the loop will not finish unrolling until it is a long way out there, maybe as far as 150’.

How do I delay this turnover? With regular lines it is done with tapers, and integrated shooting heads are excellent tools. However, even with integrated heads, the amount of overhang is still critical. Overhang is the amount of running line between the tip of your rod and the back of your shooting head when you release the line. Most people say between 4’ and 20’ of overhang is appropriate. Overhang has an exponential effect on the amount of time it takes a loop to turnover. An added foot of overhang might get you 10 feet of additional distance. The problem is, the further away from your tip the head gets, the more it feels like slinging a rock on a string, because the thin level line transfers very little energy into the dense, heavy head. This is a matter of practice, but as a general rule, the longer the length of the flyline an angler can control, the further away the cast will land. I taught a beginner yesterday with shooting heads on a 15’ rod. That extra length of rod gave her an elevation advantage and thus more leverage on the line, which meant more energy. She was able to swing a 30’ head with almost 10’ of overhang, and she hit the 100’ mark on her first day. (Warning: results not typical.)

Grains of What?

A note on grains. Flylines are measured, as I stated, in grains like bullets. Sinking lines can be “density compensated,” with more of those grains at the tip, to keep the line sinking all at the same rate. While a level line with an even density would sink in a straight, horizontal line if laid out on the water, a tapered line with an even density will not. The thinner tapered portions on the front and the back of the head will simply weigh less than the middle, with the result that the middle will sink in a big U in the water. Density compensated lines work to add grains up front by increasing the mass of the thinner areas, resulting in a straight drop.

When calculating shooting heads, it is often a good idea to figure out what amount of grains the average line for that weight of rod weighs and choose a head that is two weights up. Why is this? The old AFTMA line standards were decided before the days of saltwater flyfishing and the long cast technology that grew out of it. Thus, lines are measured only by the grain weight of their front 30 feet. However, anglers today commonly carry far more than 30’ of line in the air, so if you are used to a rod bending a certain way down the blank, but you usually carry 45’ of line in the air, a shooting head that is only 30’ long, even of the same weight line, is not going to bend the rod as far. Additionally, shooting heads are kind of a one-shot deal. You don’t get a lot of time to develop linespeed but must rely on the initial release of energy from the rod into the line to impart enough power to make the line stretch out further. Just as a spring compressed farther will jump higher, a rod under greater load will release with more energy. Generally, two line weights are a comfortable margin, but many rods will carry even heavier weights with good results.

I hope this information helps you make a more informed choice the next time you purchase a line. See our Beginner’s section for discussions (not all of them for beginners) on how to better impart energy from the rod into the line through casting technique.