The issue of the misstatement of diameters and breaking strains of fishing line is a critical issue for any angler concerned about catching fish.
It is a serious problem within the sport fishing line market in the UK and Europe caused by the misstatement of diameter and breaking strain information on packaging by companies wishing to gain sales by making their products appear better than they actually are.
This situation has existed for many years but has grown worse in recent years. There is a great deal of comment and unrest amongst the more informed angler around the country as to how this can be allowed to persist.
The effect of this misrepresentation is to give those companies carrying it out an advantage in the market as consumers are led to believe that their products are stronger and thinner (and therefore better) than they actually are.
The critical factor determining the performance quality of a line is its diameter and its breaking strain and the relationship between the two. The stronger a line is for its diameter the better.
There are two types of misleading information. Firstly simple exaggeration of breaking strain where companies claim considerably higher performance that is actually true in reality and secondly stepping up of diameter where companies supply a thicker line than stated to increase the breaking strain.
This is mainly practiced by southern European producers who generally state the correct or close to correct diameter, but then make inflated claims on the label regarding the breaking strain up to almost double what it actually is. The main culprits in this area seem to be Italian and Spanish companies but this practice also goes on in Eastern Europe.
Shown are tests shown conducted by the European Fishing Tackle Trade Association in 2005, and that were published in Tackle Trade World Magazine in August 2005 that show how much the actual strength falls below what they claim.
This is a fairly straightforward case of overstating the actual linear test performance of their product. Responsible companies will tend label their products around 10% below the actual breaking strain.
Company | Product |
Stated Ømm |
Actual Ømm |
Stated B/S kgs |
Actual B/S kgs |
B/Strain % Variance +/- |
Colmic | Fendrel | 0.30 | 0.313 | 12.1 | 7.97 | -34.1% |
Tubertini | Tatanka | 0.26 | 0.277 | 9.30 | 5.86 | -36.9% |
Falcon | Prestige | 0.22 | 0.216 | 6.65 | 3.68 | -44.6% |
Falcon | Planet | 0.20 | 0.216 | 6.35 | 3.70 | -41.7% |
Maver | Dual Band | 0.18 | 0.218 | 4.70 | 2.94 | -34.4% |
This practice is a little more subtle but is equally misleading with possibly more detrimental consequences for the consumer. It has also been practiced for many years and has become accepted and common knowledge that it is the practice for certain brands. The most notable brand has been doing it for 35 years. This involves supplying a higher diameter than that stated on the label to make the line stronger than it would normally be for the stated diameter and appear to be stronger for its diameter than it actually is. There is normally a range of diameters and the one above will be actually put on the spool of the one below.
Brand 1 | |||||
Stated Ømm |
Actual Ømm |
Diameter % Variance +/- |
Stated B/S kgs |
Actual B/S kgs |
B/Strain % Variance +/- |
0.08 | 0.112 | +40% | 0.5 | 0.73 | +46% |
0.12 | 0.150 | +25% | 1.0 | 0.90 | -10% |
0.14 | 0.175 | +25% | 1.2 | 0.98 | -18.3% |
0.15 | 0.192 | +28% | 1.4 | 1.61 | +15% |
0.17 | 0.208 | +22.4% | 2.0 | 1.80 | -10% |
0.20 | 0.233 | +16.5% | 2.4 | 2.37 | -1.2% |
0.22 | 0.261 | +18.6% | 2.7 | 3.47 | +28.5% |
0.25 | 0.282 | +12% | 3.5 | 3.89 | +11.1% |
There can be no defence that it is within a notional level of tolerance as the diameter actually used is higher than the stated diameter of the next item up in the range.
In most cases the breaking strains don’t match up to the claimed breaking strains either. These products are aimed at competition anglers who are fishing matches for both prestige and prize money.
Using the thinnest diameter possible improves bait presentation and therefore bites and catch rates so a lot is at stake based on using the thinnest strongest line. The figures shown above for the percentage increase shown is of course only part of the story as this is for the diameter. The actual cross section area increases much more and significant, as per the examples below.
Brand 2 | |||||
Stated Ømm |
Actual Ømm |
Diameter % Variance +/- |
Stated B/S kgs |
Actual B/S kgs |
B/Strain % Variance +/- |
0.08 | 0.094 | +17.5% | 0.81 | 0.65 | -19.8% |
0.09 | 0.113 | +25.6% | 0.97 | 0.63 | -35.1% |
0.10 | 0.134 | +34% | 1.21 | 1.24 | +2.5% |
0.11 | 0.140 | +27.3% | 1.52 | 0.97 | -36.2% |
0.13 | 0.159 | +22.3% | 2.14 | 1.77 | -17.3% |
0.15 | 0.181 | +20.7% | 2.68 | 2.50 | -6.7% |
0.17 | 0.200 | +17.6% | 3.09 | 2.44 | -21% |
0.19 | 0.217 | +14.2% | 3.36 | 3.26 | -3% |
As an example we take one of the lines above and show how much thicker the line actually is than it claims both in diameter and in cross section.
This is bad enough when you look a simple diameter comparison. It is even worse when you consider how much thicker the line is in two dimensions.
As an example we take one of the lines above and show how much thicker the line actually is than it claims both in diameter and in cross section.
Diameter Variation Comparison of two different lines claiming to be 0.10mm
Stated Diameter 0.10mm |
Actual Diameter 0.134mm |
So this seems pretty clear. A well-known line states that the diameter is 0.10mm but when measured it is actually 0.134mm - 34% thicker than stated. Fairly outrageous you say. Particularly when they sell a 0.11 a 0.13mm in their range.
The Actual diameter width is 34% greater than stated.
But wait it gets worse. We are measuring in one direction here. The line is thicker in ALL directions. So the thickness of the line is not 34% more it is 79% more! Just think how this will affect your presentation and catch rates.
Cross Section Variation Comparison two different lines claiming to be 0.10mm
Stated Diameter 0.10mm 0.0247mm² |
Actual Diameter 0.134mm 0.0443mm² |
The cross section area is 79% greater than stated.
Many anglers realise this and avoid these sort of line or allow for their inaccuracy. Many more anglers however don't which means they cannot make accurate choices and therefore are at a disadvantage particularly in match fishing situations where money is involved.
It is quite possible for any manufacturer to maintain his tolerances to within 5%.
The above calculations are made by using the basic formula for area of a circular cross section πr²