How to Make Sure You’re Using the Right Strength Fishing Line

Determine the Wet Breaking Strength and Fish the Strength You Want

Photo © Ken Schultz

Elsewhere I explained what the strength label on a spool of fishing line signifies and how most people don’t really know what they’re getting when they buy a new line. What do I mean by “don’t really know?” What the label says is not what you’re actually getting. We’re delving deep here into a technical fishing topic that many anglers simply don’t care enough about, but if you’re meticulous about fishing, like me, you may want exactitude.

This is especially true if you’re a light-tackle, light-line aficionado.

The net-net about labeling is that most line packaging doesn’t explain that the line is actually stronger than labeled (true for the vast majority of test lines) and that what really matters is where the line breaks when it is in a wet condition. Lack of uniform labeling and standards for labeling is a decades-old issue. Line manufacturers and distributors are not likely to come together and establish standards that all can agree to. This is largely because everyone’s quality-control abilities aren’t the same; and some are slicker at marketing than others.

How to Test Your Own Line

Why would someone knowingly want to fish with a mislabeled line, say a labeled 10-pound line that actually has 15-pound breaking strength? Maybe because they tie lousy knots. For example, if you regularly tie an Improved Clinch Knot that only gets 75 percent strength (the knot breaks when 75 percent of the line’s breaking strength is mustered), then you still get 11.25-pound breaking strength from the line.

However, that’s goofy reasoning. Learn to tie the knot perfectly so it delivers 100 percent strength, and use a fishing line that is really 10 pounds instead of 15.

How can you figure out how strong the line really is? One way is to test it yourself (harder), and the other is to ask (not as hard but still a nuisance).

To test it yourself, you need a force gauge or good-quality digital scale. Wrap the end of the dry line enough times around the hook of the gauge or scale so the line won’t slip when pulled, then apply enough pressure to break the line. Do this a few times to get an average dry breaking strength. Then soak the line in lukewarm water for about 20 minutes and perform the same test in a wet state, doing it a few times to get an average. The needle stays put on a force gauge, making reading easy, while it returns to zero on a digital scale when the line breaks, making reading harder.

To ask, you need to contact the manufacturer and ask for the wet breaking strength of specific products. Some guides, charter boat captains, competitive anglers, and writers do this. A small number of dedicated record hunters have been doing this for years, and only fish with line that they are certain about the wet breaking strength of. Of course, the information that you get this way is good for the current product made by that manufacturer, but may not hold in perpetuity.

End-Run Solution: Drop Down

If you find that the labeled 10-pound line of a brand you like actually breaks at 13 pounds when wet, and you prefer to fish with a line that has 10-pound wet-breaking strength, then check out that manufacturer’s labeled 8-pound line, which you may find breaks in the neighborhood of 10 or 10.5 pounds when wet.

Use the labeled 8-pound line to really get 10-pound breaking strength if that’s what you feel is best for certain fishing conditions. This is a way to do an end-run around the problem, plus you wind up using a smaller diameter line, which is often beneficial.

You shouldn’t have to drop down, and many anglers won’t bother, but that’s how it is with test line. Be advised that numerous anglers have submitted a line-class world record application to the International Game Fish Association, only to have it rejected because testing shows that the line is stronger than labeled, and the fish does not qualify for that line-class category. They are heartbroken or at least disgusted when they get the news.

You do have the option of paying a little more and fishing with a class line instead of a test line.

Meanwhile, if a friend says he caught a particularly large fish on 6-pound line, you can really befuddle him by saying, “yeah, but what’s that line’s real breaking strength?” There’s a 90 percent chance he’ll be clueless.