Introducing TackleTour's FPI  Fluorocarbon Performance Index
(continued)
Strength (Total of 30 possible points)
Material Strength (MS): Rarely are two fishing lines rated equally in terms of breaking strength produced in the same diameter. To equalize the playing field so we can get an idea whether the material in one line is stronger than the other, we get as close as we can in line diameter (as stated earlier between 0.29mm  0.33mm) across brands, run our tests, and divide tensile strength readings of each line by their respective cross sectional area.
The Machine allows us to quickly tabulate test data.
We then compare this number against the average value for material strength from our 2010 fluorocarbon Showdown, determine the percentage over or under our test line is in comparison to this average, and multiply this percentage against the number five, the mean or average between 0 and 10. If a product rates better than average, its score will be between five and ten. If it's less than average the score will be between one and five. This result is added to our performance index to represent a product's material strength.
FPI Material Strength (MS) 
Material Strength of Review Sample 
Avg MS from 2010 FC Showdown 
Calculation 
Max Value 
MS 
Avg MS 
(MS/Avg MS)*5 
10 
We're careful not to put too much weight on this seemingly very important category because we've found the strength to diameter ratio in fishing lines is not a linear value. Meaning tensile tests run across varying diameters of the same line normalized through our formula of dividing the line's breaking strength at each diameter by the cross sectional area of the line does not produce the same material strength numbers. So our best method of comparison is to choose diameters that are close (0.29 mm  0.33 mm are within 8.8% of one another) and just compare numbers against the average of a large sample size. If our sample matches the average, it receives the average score of 5. If it out performs or underperforms the average, its score is increased or decreased accordingly but only as a percentage.
Knot Strength vs Rated (KS v RS): Working on the assumption that a line's rated strength will always be a lower value than it's actual breaking strength, this is where we give manufacturers the benefit of the doubt for under rating their line. By dividing a line's knot strength against its rated value, we give that line the opportunity to score higher as a percentage when compared to its actual breaking strength. This percentage is then multiplied by 10 giving us the second knot strength value to add to its FPI.
FPI Knot Strength vs Manufacturer's Rated Strength (KS v RS) 
Manufacturer's Rated Strength 
Knot Strength 
Calculation 
Max Value 
RS 
KS 
(KS/RS) * 10 
10 
The simplest method of testing knot strength is to tie and overhand knot in the middle of a length of line and stretch that length until it breaks.
Knot Strength vs Tensile (KS v TS): When it comes down to it, even more important than a line's overall tensile strength is its knot strength. We already know that on average, fluorocarbon's inherent knot strength is pretty poor. What we want to know is how does a particular line's knot strength compare to its tested tensile strength. In a perfect world, they'd be the same value, but of course, this is not possible. The weakest point along any length of undamaged fishing line is the knot. We test knot strength by tying an overhand knot in the middle of the line and measuring the value at which the line fractures with that knot in its length. We translate this to a percentage by dividing the break value against the line's tested tensile strength and then multiply that percentage against 10 to determine its score in this category.
FPI Knot Strength vs Tested Tensile Strength (KS v TS) 
Tested Tensile Strength 
Knot Strength 
Calculation 
Max Value 
TS 
KS 
(KS/TS) * 10 
10 
Stretch (Total of 10+ possible points)
Stretch (STR): Through our 2010 fluorocarbon Showdown, we were able to determine all fluorocarbon lines stretch. This in and of itself is not a bad thing because depending on the technique you're fishing, you want some give in your line to help absorb the shock of your hookset or even hard, unexpected strikes from a fish. But when manufacturers claim a product does not do this, or does do that, we're going to find a way to call them out on these claims to keep them honest, and the early claims of fluorocarbon lines were that they didn't stretch.
FPI Stretch Rating (STR) 
Average Stretch 
Tested Stretch 
Calculation 
Max Value 
AS 
TSt 
(AS/TSt) * 5 
5+ 
Combining our stretch data from 2010 together with our tests over the past several months, we've determined that in general, fluorocarbon lines stretch on an average of 10.5%. To determine a line's score in this category, we calculate how far above or below it tested against this average, convert that value to a percentage, and multiply that by the number 3  the mean between one and five. If a line behaves phenomenally in this category, there's a chance it can score more than 5 points, but realistically, the score will likely fall between two and four.
FPI Deformity Rating (DR) 
Average Deformity 
Tested Deformity 
Calculation 
Max Value 
AD 
TD 
(AD/TD) * 5 
5+ 
Deformity (DR): The interesting property of fluorocarbon line is once you subject it to a constant load and stretch the material, it does not necessarily recover 100% once the load is removed. It elongates. The average amount a length of fluorocarbon permanently deforms once load is applied then removed is just under five percent. Once again we calculate the percentage above or below a product performs against this average and then multiply this percentage against the number 3. Similar to our stretch category, there's a chance products can score more than 5 points if they perform phenomenally against the average, but most scores in this category will also fall between two and four.
Abrasion (dynamic score)
The last factor we add in our Fluorocarbon Performance Rating is for abrasion. How many cycles will a line survive on our abrasion machine before breaking? We run each test subject through five iterations, subtract the high and low, then average the remaining three. No factors here. We just add this average number to our performance index straight up, so a line can perform rather poorly in all of the above categories but be outstanding in abrasion and make up lost ground. Conversely, a line can do very well in all of the above categories, but do poorly here and lose ground.
Resistance to abrasion is one of the primary factors for choosing fluorocarbon as your main line or leader material. Seriously, if a fluorocarbon line behaves poorly in abrasion tests, you almost might as well just save your money and use a nylon monofilament as your main line. Nylon monofilament is not as sensitive as fluorocarbon nor does it possess the mystical refractive index, but the cost is significantly less. Resistance to abrasion is one of the key advantages of fluorocarbon over all other line materials and it is weighted in our performance index accordingly.
TackleTour's Fluorocarbon Performance Index (FPI)  Initial Sample Run 

Quality (20 points) 
Strength (30 points)

Stretch (10+ Points

Abrasion Cycles

F P I


PW 



KS v RS 
KS v TS 
STR 
DR 
Possible Points 
5 



10 
10 
5+ 
5+ 
No Limit 

Megabass DragonCall (12lb) 
5 



6.2 
6.1 
2.7 
3.6 
21 

Vicious FC (10lb) 
0 



6.3 
4.1 
2.4 
2.1 
18 

Seaguar AbrasX (12lb) 
5 



6.8 
7.0 
2.7 
3.7 
11 

Seaguar Tatsu (12lb) 
5 



9.3 
8.2 
2.5 
2.5 
22 

Conclusion: Comparative analysis is the bread and butter of TackleTour. Thanks to our new Fluorocarbon Performance Index (FPI) we can now quickly report on the latest and greatest fluorocarbon lines and give you, our readers, an initial impression as to what to expect in overall quality and performance. Of course, this begs the question, what about braid and mono? And does copoly really give us the best of two materials or is it more like a crossover vehicle and built to please the masses but not really tough enough for serious enthusiasts?
Get ready for an avalanche of reports from our lab on the latest and greatest in fishing lines.
Rest assured, our BPI (Braided Line Performance Index), MPI (Nylon Monofilament Performance Index), CPI (CoPoly Performance Index) formulas are all set and ready to go and in the coming weeks, after we've had a chance to run through some tests and collect the data, we'll be debuting these indexes as well.