Making enough line to go around the World nearly 34 times each year, Sunline has the largest stand-alone line factory in the World. Despite making so much line every year, quality and accuracy are guiding principles for producing every spool of line that Sunline makes. Sunline manufactures their lines to strict diameter tolerances that require a specific diameter range for each lb test. These diameter specifications hold across the globe for any line we offer.

Japanese Fishing Line Laws

Japanese laws require line companies selling in the Japanese domestic market to label lines with a specific lb test based on pre-determined diameter ranges. This policy ensures lines rated at a particular lb test will break at that lb test for factual accuracy.

The accurate measure of a line or fiber is the denier rating. Denier is a unit of measure for the linear mass density of fibers. It is the mass in grams per 9000 meters of fiber. This accurately measures the strength of a line or fiber and allows the strength of different materials to be compared regardless of the diameter. One fiber may have a higher breaking strength because it is larger in diameter, but that does not mean it is stronger; it is only thicker in diameter. Denier allows fibers to be tested and compared regardless of diameter for a proper comparison.

European Fishing Line Laws

European companies selling line are also held to a similar standard for diameters with the EFTTA Line Charter. The charter is a pledge by over 35 line manufacturers stating they will only manufacture lines that meet agreed-upon standards. A few of those include:

• To print clear and accurate descriptions of their products in terms of diameters and breaking strength that are easy to understand, truthful, and respectful of consumer protection laws and industry standards, in compliance with the ISO 2062 Standards.
• To run quality controls in sufficient quantities and often to ensure that product labels are always accurate.
• Not to use any other labeling in terms of breaking strength that is not scientifically demonstrated or agreed upon by the industry to avoid any confusion among consumers leading to unfair competition.

United States Fishing Line Laws

So, what about the US? There are no such guidelines or charters in the US market regulating diameters. Line companies can produce and label a line with any lb test they want. What better way to make a line seem stronger than it really is than to make a larger line and label it with a lower lb test? This will make the line seem much stronger than it really is.

Anglers think the line is strong but don’t realize they are fishing with a much more significant line size. If an angler were to catch a record fish using one of these inflated lines, the record would not be upheld when they submitted the record-catching line for testing.

Fishing Line Diameter to Pound Test Table

Let’s look at examples of Sunline Super Natural compared to other US line companies for 12lb test.

As you can see, some of the lines currently being sold in the US are much larger than the label on the spool. In some cases, an angler thinking he is buying a 12lb line is actually buying a 22lb line with a 12lb label on it.

Line Diamater's Impact on Lure Performance

As mentioned earlier, it can impact the status of record fish caught with inflated line sizes. Other ways inflated lines impact anglers are in the performance of their lures. Many lures swim or run better with lighter line. If you buy a line you think is 12lb, which will allow a lure to perform at its best, but the line is much larger, it can impact the lure's performance. Crankbaits and jerkbaits run deeper with smaller diameter lines, allowing them to reach maximum depth. Similarly, anglers that troll a lot purchase lines based on the diameter, knowing it will impact the diving depths of their crankbaits when trolled. The Precision Trolling Data shows the impact that a larger diameter can have on the diving depth of a crankbait.

Additional Resources

• EFTTA - https://www.eftta.co.uk/line-charter/
• Trolling Data - https://www.precisiontrollingdata.com/
• Denier - https://standardfiber.com/about-denier/
• Lines - www.sunlineamerica.com