Mark Sexton, who is a bait analyst for Pure Fishing, supplied the following information on fishing with Fireline. It is very informative.

Many thanks to Pure Fishing!

Fireline versus Mono for Trolling

Sensitivity is light years greater for Fireline than for mono. Because Fireline has very little stretch you can literally feel everything. This advantage is two-fold at least. For one, when a fish strikes you know immediately. It is as if the fish is trying to jerk the rod out of your hands. Also, and extremely important, is being able to tell when your lure is fouled up with weeds, algae, brush, etc. . . . Fireline can also actually interpret the substrate your lure is running into and relay that information to you through the line and rod. You can't get much more sensitive than that.

It is very simple - - - the smaller the line diameter, the deeper a lure will run. The thinner the line, the less water resistance there is on the line. Water resistance forces the line up and thus goes the lure. A good analogy is cutting a steak with a knife. Try cutting the steak with the other end of the knife once. Thinner goes deeper. The advantage of using a smaller or thinner line is that it is able to get a lure deeper compared to heavier or thicker lines. Here's where Fireline really shines. You don't lose the line strength but you decrease line diameter considerably, which in turn increases trolling depth. In our testing we found 10# mono would allow a 3/8 ounce medium Frenzy diver at a standard average retrieval speed (2.64 feet per second) and at a casting distance of 60 feet to dive to 9.9 feet. The exact same scenario with 10# Fireline gets the lure to 10.4 feet. That is a pretty good difference at only 60 feet. Now you are looking at less line out to reach your depth, which helps in sensitivity. The fact is you will have so much more feel with Fireline that your options for trolling have been seriously increased. If you decide to leave a lot of line out and hit deeper depths, the incredible lack of stretch Fireline has allows better long-range hookups. For short lining it just gets better. Also because there is less energy being exerted on the line the lure is allowed to run "more free" which gives a little extra action.

Things to keep in mind when using Fireline over mono for trolling---Downsize on rod stiffness. You need a soft tip rod and the reason for this is easy to visualize. When you set the hook using monofilament, the line stretches considerably and absorbs a lot the energy or shock if you will. A good strong rod was the right choice to help in driving the hook home. With Fireline there is virtually no stretch and thus the energy or shock has to go some where. A heavier rod with Fireline on a hookset can cause a couple of backfires. The hooks can straighten out or a larger than optimal hole can be created where the fish is hooked. The fish has a much better chance of throwing the lure when this happens. So use a softer rod which will absorb most of the shock on a hook set. The same thing goes for the drag on your reel. Loosen it up a couple of ticks. This just allows the shock to be partially absorbed at a place other than on the hooks. I read once that you set the drag based on the diameter of the line not the lb. test. It makes sense now that Fireline is the choice line for trolling.

Bottom line is that Fireline is untouchable when it comes to trolling. The sensitivity alone is worth using Fireline not to mention depth increases and better hook ups. Here's the chart on the diameters of Fireline at the different lb. tests.

Fireline Lb. test vs. Monofilament equivalent
in diameters

Fireline (4) / Monofilament (1)
Fireline (6) / Monofilament (2)
Fireline (8) / Monofilament (3)
Fireline (10) / Monofilament (4)
Fireline (14) / Monofilament (6)
Fireline (20) / Monofilament (8)
Fireline (30) / Monofilament (12)

Good Fishing,
Capt. Dave Adams