GSP core of Monic lines

[Zhongxiang]

Hi guys,

I'm very curious about the GSP core of Monic fly lines. As it claims to be a thinner core thus contributes to a smaller diameter fly lines overall. I haven't got hands on one though, anyone knows the diameter difference and the line stiffness?

Cheers
TC

[Lasse Karlsson]

I have an old monic runningline, very thin, no stretch, so there's memory that hardly goes away, but its quite limp, and strong as hell.
See if I can dig it out tomorrow and measure if no one beats me to it

Cheers
Lasse

[Mangrove Cuckoo]

Bart,

I have had the opportunity to try a number of Monic lines, and I particularly like their GSP cores for tarpon fishing. I find their no-stretch property of that core to be advantageous for setting the hook into that tough to hook species.

However, depending on what density of line you are looking at, I would suggest you try to get some data on the diameter of the line, not just the core.

A thinner core may allow them to make thinner lines, with their particular polymer, but that does not necessarily mean their lines are thinner than competitors.

Different polymers have different inherent densities, and that means different volume to mass ratios.

I have not gone to measuring with calipers, but trying to maintain a certain amount of backing on a reel can tell you a lot about how much space typical lengths of same weight flylines occupy on particular reels.

Capicse?

[James9118]

Hi TC,

Don't get into thinking that 'magic' can happen with changing the core of a fly line in order to effect the overall diameter - Archimedes principle tells us this simply isn't possible (irrespective of what some clown selling lines tells people).

Let's take a simple example of a #7 floating line and look at the constraints on the physical properties:

Firstly (and assuming it adheres to the AFFTA standard), the first 30ft (914.4cm) will weigh 12 grams.
Secondly (and this is an absolute), in order to float it's density must be less than 1 g/cc.

Therefore: density (mass/volume) <1
hence: 12 / (pi.r^2 x 914.4) <1

Now this gives a limit of diameter > 1.3mm for a #7 floating line.

Irrespective of the core, that's the thinnest a floating #7 line can be. Bear in mind that at a density of just less than 1.0g/cc the line is barely floating, most manufacturers will target a density of 0.8 - 0.9 g/cc in order to avoid complaints that their lines sink. This obviously pushes the actual diameter higher - I've just measured my MED #7 and it's 1.45mm diam.

I guess the point is that for floating lines the density, diameter, strength etc. of the core doesn't matter one bit in relation to the overall line's diameter, what matters is the composite density of the line's cross section (and this can't be greater than 1g/cc).

However, if we're talking about sinking lines then obviously increasing the density will reduce the line diameter for any given AFFTA number - it will also increase the sink rate of the line.

Cheers, James

[Zhongxiang]

Thanks a lot for the info guys.

Yes, James. I agree with the theoretical absolute value of minimal 1.3mm. I recall we have discussed about this a few years back while in Jersey when talked about a brand that now claims orange pigment is poor for energy transfer.

What I'm curious about is the relative difference in diameter. My #7 Med has similar measurements of 1.47-1.48mm at thickest part. I have also measured other lines although some are for tropical SW I have fished them in freshwater as well and they still floats:

lines 30ft weights thickest dia
Snowbee #7 190gr 1.37mm
Cortland flat taper #7 200gr 1.3mm
SA bonefish #8 210gr 1.4mm

I remember Paul mentioned a small batch of Med #5 uses a very thin core that easily breaks to reduce diameter? Is he wrong again?

Cheers TC

[Zhongxiang]

A thinner core may allow them to make thinner lines, with their particular polymer, but that does not necessarily mean their lines are thinner than competitors.

Thanks for the input

[James9118]

Hi TC,

It's possible that flats lines are thinner because saltwater is denser than fresh, hence manufactures can push the density of the lines up from 0.8 - 0.9g/cc without the danger of them starting to sink (they won't be quite as buoyant in fresh water though).

Yes, Paul is wrong. Unless the line was denser than normal, or lighter than the AFFTA rating, then it can't possibly be thinner (unless he was just referring to the running line).

Obviously the taper has to be considered - the above is all based on a level line. The principles are the same though once you know the exact taper.

Cheers, James

[James9118]

By the way, the RIO tournament line has a very thin running line because it's built on a low strength/ low diameter core. However the head bit, i.e. the bit that has to meet the AFFTA spec, is the same diameter as any other line.

[Paul Arden]

Yes, Paul is wrong. Unless the line was denser than normal, or lighter than the AFFTA rating, then it can't possibly be thinner (unless he was just referring to the running line).

I can’t remember if the head had the same or smaller diameter. Lasse will remember because he always does. The running line however was extremely thin. I think the core was 10lbs mono. If Lasse can’t remember I know someone who might, although from recent emails I think Bruce’s memory might be even worse than mine

[Lasse Karlsson]

Bruce made a small batch of MED5 with a monocore that according to Paul went further than the normal, didnt get my hands on it though.

If heads are same diameter and weight and lengtg, the one with the thinner ie. lighter runningline has the potential to go furthest. And MED is also made to be closer to the 1g/cc to get them as thin as possible, one of the reasons the tip tend to sink realativly easy when fishing.

Cheers
Lasse