Tactics & Tackle
Line Logic
by Mark Sosin
Fishing line gets no respect. It's the only link between an angler and his quarry and, in scientific parlance, the strain member of the system. Line takes much more abuse than the fibers in a bent rod or the washers in a reel drag. One would think that fishermen would focus on the properties and performance of monofilament (or braided Dacron), but most choose to ignore it. To many, line ranks as a homogeneous product with price serving as the most important difference.
In today's marine world, monofilament overshadows Dacron by a massive margin. A handful of specialists who jig or fish bottom in relatively deep water prefer it because it doesn't seem to belly as much as mono and offers different characteristics. Dacron has negligible stretch, making it easier to set the hook and to pump a fish from the depths. In the tradeoff, it's much less forgiving. Some big game anglers and particularly those pursuing giant bluefin tuna insist on it for those same reasons. Fly enthusiasts use Dacron as backing on their reels behind the flyline. And those who fly fishing kites opt for it, although there are a few experts who spool mono to fly a kite.
All monofilament reflects a balance of properties. If you reduce elongation (stretch), it affects something else. Tensile strength (break strength), elongation, limpness, diameter, and abrasion resistance all figure into the equation. The stated break strength reflects a dry line. Nylon absorbs moisture from the air (or loses it). Putting the line in water accelerates this process up to the saturation point. It is not uncommon for saturated monofilament to lose 10 percent of its breaking strength or more.
Once again, there's a tradeoff. As the line begins to saturate, the amount of stretch increases. This makes the line less brittle and its overall toughness goes up because it is more forgiving. Polymer chemists tell us that line is more prone to breakage when it is dry, even though the tensile strength is greater.
The International Game Fish Association (IGFA) tests lines for record purposes after two hours of submersion in water. They measure the break point only. A number of line makers and spoolers offer tournament-tested line guaranteed to meet the line classes established by IGFA. Unknowing anglers erroneously believe that these lines test right at the designated class. They think that 30-pound test breaks at 29 pounds or 50-pound test fails at 49.5 pounds. It doesn't happen that way in the real world.
In the last decade, polymer chemists have made tremendous strides in producing better lines, but aspects of the process still exist that require further refinements. They cannot measure the carbon bonding of the molecules throughout the line, detecting weak spots or exceptionally strong areas. The inability to insure uniformity in strength forces them to invoke a safety factor and keep the guaranteed line a respectable margin under the threshold of failure. Working with the molecular building blocks is not an easy task.
Fishermen are beginning to learn that finer diameter lines offer a number of advantages. They help to present a bait or lure more naturally, cast better, offer less resistance in the water, and are not quite as visible to the fish. You'll find, however, that as diameter decreases the line is not quite as forgiving.
Monofilament can be compared to a spring. As long as you stretch a spring within its limitations, it will return to its normal position repeatedly. If you exert too much force and pull a spring beyond its limitations, it will not return to its original shape. This is called non-recoverable deformation and it happens to monofilament.
It can happen when you are fighting a fish to the maximum, but the most vivid example occurs when you hang up on the bottom and have to break the line. You clamp down on the line and pull steadily until the line snaps. There's a good chance you reached total strain energy and the section of line between the reel and the broken end will never be as strong. You have reached non-recoverable deformation and destroyed some of the stretch. That's one reason (nicks and abrasions are the others) why some very serious anglers change line after a long, hard battle with an exceptionally large fish.
Most of us assume that uniform strain exists along the entire line when we fight a fish. Indications demonstrate otherwise. When you hang up on the bottom and break the line with a straight pull, it seldom fails right at the hook unless it cuts on a sharp object or acquires a stress concentration from a nick. Frequently, the line breaks right at the tiptop of the rod which is one area of serious strain.
The fish often loads the other end through its movements. That's the reason that inferior or poorly-tied knots tend to fail. The impact is transmitted from the hook. It reaches a weak spot (the knot) and POW! The longer the length of line to absorb that impact (assuming relatively uniform strength), the less damaging it becomes. That's why lines break when fish surge away close to the boat. You have a short length of line that deprives you of adequate elongation (stretch) and you pull back on the rod at the same time, increasing the shock. The preferred technique centers on dropping the rod instantly and pointing it at the fish as it charges away from you.
A belly in the line with a fast moving critter on one end and you on the other can create a problem. If that line is being pulled sideways through the water, the stress increases dramatically. Consider backing off on the drag when this happens. If you chase the fish with the boat, don't set off on an intercept course. Instead, follow the belly in the line, recovering slack as quickly as you can. Once you regain a straight pull on the fish, you can go back to the original drag setting and lean into the tackle.
Compromising on fishing line proves to be false economy. Quality monofilament is the best investment in the long run. Hook a trophy and, in the midst of the battle, you would gladly put dollars on the covering board if they would buy you the best line right now. If you lack experience in selecting a good line, ask others and use a line that has been proven on the fishing grounds. Monitor your line carefully. If you have abused it on fish, hanging bottom, or through abrasion, replace it. The next strike may be the fish of your dreams and there is always something missing in stories about the big one that got away.
Copyright 1998 - 2008 Mark Sosin's Saltwater Journal
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