July 17, 2019
By Dr. Jason Halfen
Contemporary anglers enjoy a wealth of possibilities when selecting the most important connection linking them to their quarry: their line.
While our grandparents may have been limited to brittle monofilament and frayed Dacron lines, we luxuriate in a comparatively vast library of modern lines, including braids, fluorocarbons and monofilaments that bear little resemblance to those used in the past.
The burden of this abundance is that we now must make choices, deciding which lines and leaders to incorporate into any given presentation. There is no single best line; rather, each type of line has its own individual strengths and weaknesses that must be evaluated in a technique-specific manner, in much the same way that we select a rod or a lure.
It All Starts With Chemistry
The evolution of contemporary fishing lines is a direct consequence of advancements in chemistry and chemical engineering over the past 50 years. Every length of line wound onto a spool and hanging from a peg at your favorite tackle retailer is a polymer: a lengthy chain of nearly identical molecular building blocks, in which the attributes of the individual small pieces — the monomers — impart specific properties on the polymer.
Consider classic monofilament line, which is a nylon polymer, much like the famous fabric used for clothing, tents and more. The building blocks of nylon interact strongly with water, so it should come as no surprise that monofilament fishing lines also absorb and swell in water. On the other hand, braided lines are typically composed of tightly-woven strands of a different polymer — polyethylene — which is fundamentally the same material found in clear plastic sandwich bags.
If you’ve ever had a sandwich bag blow out of the boat while out on the lake, then you know that the bag floats until you have a chance to retrieve it. Braided fishing lines also float, making them the favored choice for many topwater presentations. Understanding the basic chemistry that underpins fishing lines makes it easier to select the best line.
Strength and Diameter
When anglers discuss the strength of their lines, they are really discussing a mechanical measurement known as tensile strength, which reflects the force required to break the filament while it is being stretched in a straight line. Fishing line strength is quoted as its pound test, with stronger lines being associated with a higher pound test.
Need to use a stronger line? Within any given line variety — monofilament, fluorocarbon, or braid — you’ll be moving into lines with larger diameters. For example, 12-pound test Sufix Siege monofilament, a staple of many multi-species presentations, has a diameter of 0.014 inches; step up to stronger, 20-pound test mono, and the line’s diameter increases to 0.018 inches. While a difference of 0.004 inches may not seem like much, it represents a diameter increase of nearly 30 percent, which means that less of the thicker line will fit on your reel’s spool. Thicker line is also frequently stiffer and harder to handle than thinner diameter, more supple lines.
How can you enjoy the benefits of a stronger line while avoiding issues that arise from large line diameters? Most anglers move into a fluorocarbon main line or a braid under these circumstances. For example, 12-pound test Seaguar InvizX, a very supple 100 percent fluorocarbon main line, has a diameter of 0.011 inches — more than 20 percent thinner than monofilament of comparable tensile strength. The most demanding bass presentations, like punching through thick mats of vegetation or presenting hollow body topwaters in heavy cover, frequently favor braided line.
For example, 65-pound test Power Pro braid is the fiber of choice for many seasoned topwater specialists; with a diameter of only 0.016 inches, this strong braided line is far thinner than monofilament or fluorocarbon of comparable strength. Indeed, of all the currently available line varieties, braided lines provide the best strength-to-diameter ratio.
TIMELINE FOR FISHING LINE
- The Beginning: Prehistoric man used vines as fishing “line.”
- 2000 BC: Ancient Egyptians likely used flax or linen for line.
- 15th Century: In England, they begin using braided horsehair.
- 1908: Braided silk replaced horsehair for lines.
- 1939: DuPont introduced a monofilament line (very crude, almost unusable).
- 1950: DuPont invented Dacron (braided polyester).
- 1959: DuPont introduced modern Stren monofilament line.
- 1987: Dutch State Mines brought us Spectra (modern braid).
TODAY’S MODERN LINES
Modern fishing lines are mostly made of synthetic materials like nylon, polyethylene, copolymers, fluorocarbon, dacron and polyethylene. You know them as Power Pro, Spiderwire, Trilene and Sufix.
Color and Clarity
Many of North America’s most popular gamefish, including bass, walleye, trout, pike, musky and saltwater fish, are visual predators, relying on eyesight to identify and attack both their prey and our lures. As such, enhancing the visual deception of artificial presentations often calls for minimizing the visibility of the lines tied to those lures.
Braided lines, while being the strongest line at any particular diameter, are also the most visible, both above and below the water. The synthetic fibers woven together to create braided lines are opaque, making the lines easy to see for both anglers and fish. On the other hand, monofilament lines are clear, and are available in a wide variety of colors, ranging from low-visibility blue and green to high-visibility options like red, orange and yellow. Hi-vis lines are often appreciated by anglers when fishing turbid water or pursuing fish like catfish or sturgeon that identify prey using sensory inputs like scent or vibration.
Fluorocarbon lines are the least visible of all current line varieties, a distinction that results from fluorocarbon’s index of refraction (1.42) being similar to that of water (1.33). Nylon monofilament has a higher refractive index (1.58), rendering even clear monofilaments more visible underwater than clear fluorocarbons. Is fluorocarbon invisible beneath the waves? No, but fluorocarbon is less visible than any other alternative, making fluoro the “clear choice” when stealthy, finesse presentations are employed.
As noted above, nylon monofilaments swell in water, absorbing as much as 10 percent of the line’s weight in water under certain conditions. Monofilament lines are also degraded over time by exposure to ultraviolet light, losing up to 20 percent of their strength after 100 hours of UV exposure. As such, you should consider replacing monofilament line that is spooled on your reels at least once every year and ensure that your backup supply of mono is kept dry and out of the sun while in storage.
Fluorocarbon lines are exceptionally water repellent, a direct consequence of the fluorine atoms that adorn the line’s polymer chains. Moreover, fluorocarbons are impervious to ultraviolet rays, ensuring that they will not degrade or exhibit reduced performance when wet or exposed to sunlight.
The most significant aspect of fluorocarbon’s toughness, however, is its superior abrasion resistance when compared to that of monofilaments or braids. The relative hardness of fluorocarbon’s exterior helps it to shrug off contact with dock pilings, rocks, mussels and the occasional tooth without fraying or failing.
Braided lines are not particularly abrasion resistant, due in part to the fact that every braided line is composed of multiple (from 4 to 16) thin fibers, woven together. Individual fibers can fray easily when coming into contact with sharp or abrasive objects, and the failure of even a small fraction of the total number of woven fibers can lead to significant loss of tensile strength.
It is recommended that you check braided line frequently for frays and loose fibers, particularly near the knot, as well as areas that may have come into contact with hard cover. Braided lines also trap water within their woven strands, which can make braids challenging to cast when air temperatures flirt with the freezing point. This phenomenon also makes braid a poor choice for ice fishing applications, especially when fishing outside of a heated shelter.
Sink, Swim and Stretch
The different polymers used to manufacture monofilaments, fluorocarbons and braids impart distinct properties on each line when being used to present baits and fight fish.
Whether a line sinks or floats in the water is a function of the line’s density — its mass-to-volume ratio — and how the line’s density compares to that of water, which has a density of 1g/ml. Fluorocarbon lines have a relatively high density, near 1.8 g/ml, which means that fluorocarbon lines and leaders sink in water.
If you’re a topwater fan, or rely on suspending lures like jerkbaits, then a sinking line might not be the best choice. Nylon monofilaments have a lower density, around 1.1 g/ml, which means that they are more neutrally buoyant than fluorocarbons. As noted above, braided lines float, a result of their density being lower than that of water.
Each line variety has its own individual stretch and sensitivity characteristics. Nylon monofilament exhibits significant stretch, by as much as 10 to 25 percent. While this can make it harder to achieve a positive hookset at the end of a very long cast, the stretchy nature of monofilament also makes it a very effective shock absorber, particularly when a big fish makes a powerful run or dive at boatside. Because of mono’s ability to stretch, it is the least sensitive line option.
Fluorocarbon lines exhibit significantly less stretch—just a few percent of the line’s original length—which makes for more effective long-distance hooksets and enhanced sensitivity. At the same time, because fluoro has less stretch, it is not an effective shock absorber. Braided lines do not stretch at all, and as a result are the most sensitive, and least forgiving option.
The Best of Both Worlds?
With all of these choices, how can an angler choose a line or line-leader combination that accentuates the positives and minimizes the negatives? For many anglers, in both fresh and saltwater, the choice is simple: use a braided main line for the best strength-to-diameter ratio and optimum sensitivity, tied to a fluorocarbon leader to minimize line visibility near the lure and provide for enhanced abrasion resistance.
If you travel down this path, then you’ll need to learn to tie a robust knot that links the braided main line to the fluorocarbon leader. Many such knots, such as the Double Uni-knot and the FG knot, you can learn with a quick YouTube search, and each has their own particular strengths and weaknesses. Pick a knot that is easy for you to tie, in daylight and low-light conditions.