The strength of a fishing line measure itself in pounds. It shows how much weight the line can lift or last before break. Test lines list according to the lowest breaking strength.
If line marks 30 lb test, the maker ensures that it tests at 30 lb or more. In actual use the breaking strength range according to making tolerances, surroundings, how you handle it and the type of knot. Line loses up to a third of its force at the knot.
How to Choose the Right Fishing Line
So it matter well size the fishing line. Although the real breaking strength usually goes over the rating by around 15 %, the knot stays the weak spot.
Various kinds of lines answer to different uses. Monofilament is the usual line for everything, since cheap rod and reel combinations until saltwater pros or large river fishers. It sinks more slowly than fluorocarbon and keeps knots well.
In freshwater 4-12 lb tests are used. For small trout or sunfish you choose 4 lb test. For trout you cast usually 4-pound line.
Intending bigger fish like musky or pike, use 20-30 lb strong line. For tuna of 30 pound class the line must match the weight of the fish.
Braid answers as mainline because of two main advantages. It does not remember the form of the spool. Memory happens when line adopts the curved form because of time and tension.
Lines without memory straighten right away from the spool. That reduces friction on reels and guides, so you can cast more smooth and long. Using braid, choose by diameter, not only by breaking strength.
Braids from Spectra or Dyneema are the strongest. Current fishing lines reach 250, 350 pound test. If you want stronger line without thickness, try braid.
Too heavy line creates troubles. Fish see it more easily in water. It also affects the swimming action of lures.
Rod of 20-40 pound class must handle lines of 20 until 40 pound test with drag of 7-14 pound. Around structure or in hard runs use leaders, tapers or shock leaders. Usually the drag set to 1/3 until 1/4 of the force of the weakest part, so the leader.
If drag surpasses the line weight, breaking risk grow. Casting of pier only some yards out, match the drag strength to the line weight.