How To Test Fishing Line For Abrasion Resistance

by John Merwin

In last week’s post I mentioned that this week I was going to talk about abrasion resistance in fishing lines. The ability of different types and brands of line to withstand being rubbed hard over any rough surface is obviously important. When a hooked fish drags your line across an underwater rock, you are of course hoping--maybe even expecting--that the line won’t break.

Line companies make all sorts of claims as to the abrasion resistance of their respective products. And it’s quite true that some lines are more abrasion resistant than others. The problem comes in the way in which manufacturers measure abrasion resistance, which to my mind bears little relation to actual fishing situations. I think dragging a line under tension between your hands and across a rough-surfaced rock (as shown in the photo) is the best test. But first, let’s look at what the line companies do.

A standardized material testing is a whole science unto itself. Procedural specifications are rigorous because the way in which things are tested has to be precisely repeatable by different labs at different times. This just means comparing apples to apples as the results of different tests are compiled.

The common lab test for the abrasion resistance of fibers--including fishing lines--works like this: A weight is tied to one end of the line. The line then passes over a sandpaper-covered cylinder so the hanging weight keeps the line under tension against the abrasive surface. The other end of the line is attached to a machine that cycles the weighted line back-and-forth repeatedly against the sandpaper. Eventually the line wears through and breaks. More cycles before the break means the line has more abrasion resistance. Fewer cycles before break means less abrasion resistance. And that (somewhat oversimplified here) is how line companies test lines and make their abrasion-resistance claims.

The real fishing world is quite different. Here a hooked fish is going to drag your line across rough rocks along the bottom, or sharp coral rubble in saltwater, or a piling or barnacle-encrusted rock in the surf. That’s why I test abrasion resistance by dragging a line across a rock sideways, instead of rubbing the line back and forth over a rock in one spot.

Trouble is, my test is very imprecise. It works, but I can’t repeat it exactly time after time. My hand pressure varies in ways I can’t easily measure. As a practical test, I like it. As a scientific test, it’s useless.

So what about different lines? In general, when it comes to abrasion resistance I can tell you that harder is better. That is, harder-surfaced, usually stiffer lines are often more abrasion resistant than softer lines. Polyethylene-based superlines are generally soft and not very abrasion resistant. Ditto some monos and fluorocarbons.

Hard nylon monofilaments such as Mason do much better when dragged over rough surfaces. If you find a hard, stiff fluoro, that will be better, too. Those are what I use when I need to add a leader for fishing in boulder-strewn water. (Note here that I’m not talking about sharp-toothed critters like pike or bluefish, in which case I use a wire leader.)

So there you have it. Abrasion resistance, despite seeming simple, is one of the most complicated of all fishing line attributes. My advice? Forget what it says on the line box. Go find a rock and try it yourself.