Its been posted previously, but here is the stretch test I conducted recently that seems to indicate that fluorocarbon is NOT low stretch:
I used a 12 foot piece of each line and hung an 8 pound weight to see how much each line stretched in inches. Below are the results - least stretch to most stretch.
All Lines Tested
Trilene XT (Mono) 21-1/4 inches of stretch Yo-Zuri Hybrid (Co-polymer) 22-1/8 Sufix Seige (Mono) 22-5/8 P-Line CX Premium (Co-polymer) 23-1/2 Maxima Treazure (Co-polymer) 24-1/2 Trilene XL (Mono) 24-3/4 Tectan Superior (Mono) 25-7/8 Berkley Sensation (Mono) 26-1/8 Sunline Sniper (Fluorocarbon) 26-1/2 Gamma Touch (Fluorocarbon) 29-1/4 Original Blue Stren (Mono) 29-3/4 Gamma Edge (Fluorocarbon) 31-0** Bass Pro XPS (Fluorocarbon) 31-3/4* Stren 100% (Fluorocast) 31-3/4* Seaguar Tatsu (Fluorocarbon) 32-3/4 P-Line 100% (Fluorocarbon) 33-0* Seaguar Invizx (Fluorocarbon) 36-0** Berkley 100% (Fluorocarbon) 38-3/8
*Line snapped once and was re-tested
** Line snapped twice - length estimated
Broken Down By Line Type
3 Co-polymer lines average stretch: 23.4 inches
6 Monofilament lines average stretch: 25.1 inches
9 fluorocarbon lines average stretch: 32.2 inches
Line Diameter
Line diameter can have an effect on stretch, but 9 of these lines all had the same diameter (.009 inches). Those lines are broken out below. The overall results are similar for the 3 different line types.
P-Line CX Premium (Co-polymer) 23-1/2 Maxima Treazure (Co-polymer) 24-1/2 Tectan Superior (Mono) 25-7/8 Berkley Sensation (Mono) 26-1/8 Sunline Sniper (Fluorocarbon) 26-1/2 Gamma Touch (Fluorocarbon) 29-1/4 Bass Pro XPS (Fluorocarbon) 31-3/4* Seaguar Tatsu (Fluorocarbon) 32-3/4 Seaguar Invizx (Fluorocarbon) 36-0**
Overall observations
Newer Co-polymer lines being marketed specifically as “low stretch” for the most part seem to be accurate.
Fluorocarbon tends to be the line with most stretch.
Monofilament tends to be somewhere in the middle, although those with a thicker diameter (i.e. Trilene XT .011 and Sufix Seige .010) did stretch less.
Line diameter may have an effect on the stretch of certain lines, but overall, lines of the same diameter seem to reflect that Co-polymer and Monofilament lines still stretch less than Fluorocarbon.
Fluorocarbon lines tend to break easier when stretched to their maximum breaking strength. In addition, once stretched it deforms from it original state, whereas mono/co-poly returns to its original form.
If you are concerned non-fluorocarbon lines absorb water and stretch more over time, try one of the low stretch lines like Yo-Zuri Hybrid that don't absorb water.