Big Indiana Bass

Chances are, at some point, you might have wondered what, if any, are the differences between those short spools of fluorocarbon leader line and the larger traditional spools of fluorocarbon main lines? According to the folks at Seaguar, they are as follows:

Strength – While both are strong and will withstand the lb. test listed, leader is stronger over shorter lengths and is not designed to be a long, main line product.  The main lines are designed to take the impact load over a much longer distance, transferred throughout the line.

Double Structure Technology – Our FC, FP, GM, and FX leader lines are all Double Structure (2 to 80 lb.), a Seaguar exclusive process that injects two different molten resins through a special die.  The resins are extruded as one solid piece.  The harder, inside resin contributes to the tensile strength, while the softer, outside resin creates greater knot strength.  Our current main lines are single structure with the exception of TATSU, which is constructed like leader material and can be used as such.

Price – Leader is more difficult to produce because of double structure and the resins involved, therefore main line is less expensive and leader line costs more.

Resins – The resins in our main line are different than the resins in our leaders.

Lots of internet forum chatter on the subject of fishing lines, especially comparisons between fluorocarbon and nylon/copoly monofilaments, so I thought I'd revisit this study from several years back that I haven't seen anyone else mention yet. Results are from a test carried out by the German Standards Organization (TUV). The results were pretty interesting and confirmed some of what we’ve heard and/or read before concerning various research on fishing lines. There were a few new things though readers might find intriguing.

They tested 10 different brands of line based upon near equivalent diameters of .0098″, or what would most likely be considered 8 pound test in our country. These included many brands I had not heard of, or at least ones that aren’t readily available here, but there were some recognizable lines such as Trilene XL and Tectan. Highlights from the study included the following:

• About the only accurate aspect of labeling lines is the diameter stated; it is almost always very close to actual.
• All monofilaments tested had between 23%-32% initial stretch or elongation, with the bulk of them running 25%-28%.
• The spools were labeled with various breaking strains ranging from roughly 12-15 pounds.
  Actual breaking strains in a wet test (2 hrs soaked) ranged from 7-10 pounds. This is because monofilaments actually absorb moisture, which then weakens them.
• In all lines tested, when pre-stretched for one minute to 75% of it’s breaking strain, their breaking strength actually increased by 1/2-1 lb. depending on brand, and their stretch (% elongation) dropped between 3%-9% from original calculations. In other words, pre-stretching your line can make it stronger and less “stretchy”. Not certain of any downsides to this, though, so try at your own risk.
• Tests using monofilament and normal fishing rods resulted in a typical force of about 4-5 pounds being applied to the end of the line. Using an extra heavy rod and pulling “flat out”, they were able to occasionally reach endpoint forces of between 6-9 pounds.

As for the testing, their basis in reasoning was that while lines are labeled by manufacturers based upon dry breaking strength, in actual fishing conditions you are almost always using a line with some degree of water absorption. Therefore, they soaked the lines for 2 hours before testing to show what they believe better reflects "actual" breaking strength on the water, and to demonstrate the degree to which the physical properties of monofilament change (degrade) with that absorption.

They did not test breaking strength of dry lines, but there are numerous other test results on the Net showing those, and they reflect a breaking strength typically much more than the stated/labeled strength. One of the points they (German study) were trying to make in the article is that with some lines, it is not unusual to lose as much as 45-50% strength (both rated and/or actual) due to the affects of water absorption.

OK, so if you're not much of a science person, some of this might get lost in translation. Even so, you'll have to "make a leap" if you will to see where I'm going with this. This video demonstrates the impact forces and shock loading of nylon vs. Dyneema/Spectra harnesses. In our case, think monofilament vs. superlines. A few more hints:

• When they mention elasticity, think stretch.
• When they talk about drop load shocking think hookset force.
• When they do the overhand knot test think windknots.

There is a lot of great info that can be leveraged here in terms of strengths and weaknesses of how various fishing lines will perform or react. If the video doesn't make sense, there is also a small write-up with the same basic info and charts to peruse. It touches on a few other points not mentioned in the video like the differences in melting points (think knot tying and poor lubrication). You can find the written stuff at: How to Break Nylon & Dyneema Slings.