Are the ratings on a spool of line essentially a load of rubbish?

Take your typical spool of 0.35mm/15lb monofilament line, or say a 20lb 4-strand or 8-strand braid (plus whatever pile of poo PE# number is applied to it), and what do you get? On the one hand it could of course be argued that those numbers mean absolutely everything, and on the other hand it could also be argued that all those figures on a spool of line amount to little more than a figment of a company’s imagination. I am sure we all have various lines that we trust for our own fishing, but what do those actual figures emblazoned on line packaging and on the spools actually mean? And, rather importantly I might add, are they to be remotely trusted?

Let’s think about your typical spool of 0.35mm/15lb mono line then. First off, is that quoted diameter actually accurate? I am pretty sure that most anglers don’t own micrometers or other accurate means of measuring that diameter, and do I really have much interest in doing this anyway? Nope. I want to buy a line that says 0.35mm and is actually 0.35mm, but with what I read all over the internet (filtering out the garbage of course), it does seem that a number of lines seem to have these diameter claims plucked out of thin air. Should this be allowed? Of course not, but it happens all the time. I damn well want a 500g packet of pasta to actually weigh 500g, and the same with line and its quoted diameter.

And what about that quoted breaking strain? Let’s stick with this typical 0.35mm/15lb mono line because it’s nice and easy - so what does “15lb” actually mean on your spool of line? And does “15lb” mean much in real fishing terms? I don’t know if any of you have ever seen a professional line testing machine, but I have, and whilst it’s some bit of kit that shows very accurately the “clean” breaking strain of a line, does that then mean squat when we go out fishing? Let’s face it, you ain’t buying a line to look at - I presume you’re going to go fishing with it! Let’s say that this typical line (with no knots in it) does actually break at an exact 15lb on a professional line testing machine - so what I would ask. It bears little correlation to real life fishing. The same with “home testing” if you ask me - it might provide a little interest when cabin fever sets in, but what does it show when compared to actually fishing with a line in a real fishing situation?

Take that 0.35mm/15lb mono line, load it on a reel, and let’s say you then tie on a leader. Let’s be totally honest here and accept that a lot of anglers tie a lot of crap knots, but of course we won’t have it because it’s never our fault when something fails in fishing - breaking fishing rods anybody?! Even if you do know of a fantastic leader knot and tie it perfectly, putting that knot in your mainline has of course now weakened it. How much though? I must admit I don’t know, and it surely has to depend upon how good or bad that leader knot is anyway. I accept that something like the Bimini Twist is quoted as near as dammit a 100% strength leader connection, but again there has to be some element of who is tying the knot and how well they actually tie it.

Anyway, you take the line out fishing, and of course it then gets wet (I would suggest that if your line doesn’t get wet you are fishing the wrong spot). From what I read, a wet line’s breaking strain is not the same as a dry line’s breaking strain. Now I would guess that most of you are going to judge how strong you think a line is (mono or braid, makes no difference) either via how it performs when you cast heavier weights or lures, when you hook and play a fish, or when you snag up and need to pull for a break. Let’s say though that you hook a donkey of a fish and you do actually put a bend in your rod when you are playing it nice and hard - I would argue that the pressure on a line and indeed leader is very different when a big fish is thrashing around very close to you (little stretch in the line) to when it’s running away from you say forty yards out (more stretch thus shock absorption in the line). And then you have something like a marlin running many hundreds of yards and now water pressure upon your entire mainline must surely come into play etc.

It’s a bloody minefield out there with line ratings, but surely things would be so much easier for us consumers if there was some kind of standard way of measuring all lines that was then translated over to the labelling? I know you can’t actually measure the breaking strain of a line in a “fighting fish” situation for example, but it would be damn handy if we as the consumers could trust that the quoted diameter of the line was accurate for starters, and then that we knew how the quoted breaking strain had been arrived at. We as consumers can then make up our minds based on any number of different factors, and of course we all tie perfect knots anyway - don’t we?

All this applies to both mono and braided lines, and there might well be the argument that braids are the worst when it comes to suspicious labelling. We haven’t talked about how abrasion from say rocks and suspended weed comes into it, plus things like a chipped guide on your rod, saltwater and sunlight breaking down a line over time, how long you should fish with a certain line for etc. Rods, reels and lures may well be far more exciting than your fishing line, but it’s always struck me in all my fishing that whatever I might spend on getting there and buying the rods and reels and such stuff like that, at the end of the day it matters not if your principal connection to that fish of a lifetime isn’t quite what you thought it was.

I will leave you with a comment that Keith Arthur left on my Facebook page, with regards to a line for mullet fishing that a mate recommended to me. You won’t meet a nicer guy in fishing, and I was always aware that when I used to head up to London to go on the Tight Lines programme when it was around (what a shame it's gone), I couldn’t help but feel a bit of a fraud because Keith has the most incredible fishing encyclopaedia in his head - and I categorically do not! He doesn’t come across as overbearing in any way, shape or form, and I respect the hell out of the bloke, rather how much he knows about all kinds of fishing is just amazing - hence me copying his comment on fishing lines here - thanks Keith for allowing me to do this. And of course, it goes without saying, come on England, let’s grind those Welsh lads into the Twickenham earth!


“I honestly think we are fed a load of guff about lines. One maker advertised a product as 'the strongest 6lb line available' and another as 'the thinnest 6lb line available'. Now surely that should be the same thing? But no it wasn't because the 'strongest' was 20% thicker, so wasn't 6lb line at all but it said that on the label. We want to be mugged by line makers, because when the EFTTA labelling code of practice was introduced it destroyed the sales of 'honest' lines. 12lb Berkley Big Game became 18.6lb here and nobody wanted line that heavy...but when it had 12lb on the label it sold in shedfulls. Ditto Berkley Sensation: when the 4lb became an honest 7.7lb it was in the clearance bin! So fluorocarbon and copolymer mixed eh. Copolymer stretches up to 28% and once stretched never recovers to its original diameter/strength...which is why makers fib about its properties. It happens of subsequent stretches too, by the way, gradually weakening the line. If exposure to sunlight weakens it, how come it takes 600 years to biodegrade, according to scientists? Catching lots of big fish is what degrades it yet many, MANY anglers leave rods made up and use the same 30m of line for ages. (Hands up, I'm guilty!) Karl Plate (who should know a thing or two about nylon mono as his father invented it!) told me that, for a given diameter, the breaking strain could vary by 10% maximum. Obviously knots play a part in that, as does stretch, which is in itself shock absorption. The granny knot test above doesn't mean a single thing, in my opinion, unless of course the test was conducted on a line strength test machine and then it means little unless we want to know the effect of wind knots, which my granny's ghost tends to haunt me with when fly fishing. Now let's consider fluoro/copolymer hybrids. The stretch properties of both are different. Fluoro doesn't stretch half as much and tends to return closer to its original diameter than copolymer, so given similar starting diameters, the fluorocarbon would be stronger than the equivalent copolymer after a complete stretch. The image on the Yozuri website seems to indicate a coating of fluorocarbon...can that work when it will stretch less than the copolymer or does it restrict the stretch which, in my limited mind, would cause horrible potential for 'memory'. I've checked a couple of US chat forums out and they tend to conclude that it's fine on 'conventional' (multiplier) reels and mostly rubbish on 'spinning' (fixed spool) models which sort of concurs with my assumption above. The Americans would probably be catching heavier fish on it than we do, and use heavier gear - they were striper forums - so would stretch the line more, potentially. Maybe the crunch comes after an encounter with Mrs Kelp and Mr Rock have stretched it to the limit. One final point: for my past two fishing trips to Key West I have used Daiwa Floorit fluorocarbon for tarpon fishing, in 17lb. I didn't change the line from 2014 to 2015, tend to give the fish some welly on an old, regularly serviced TLD15 and a 20/30 Super Kenzaki rod. I can't break it!”