Henry Gilbey
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Henry Gilbey blog

Can the thickness of your leader ever actually affect your catch results? (the endless joys of breaking strains and diameters!)

A certain amount of the time I don’t personally believe that it does, but what about those other times? Give me a bouncing bit of sea when the water is fizzing and green and full of energy and I can’t personally recall coming away from a fishing session with the inkling that the diameter of my leader had affected my catch or indeed blank rate, but we had a guiding based situation over in Kerry last year I think it was, and it’s stuck in my mind ever since…………..

Our four lads were fishing a very shallow bit of reef in bright conditions, and three people were regularly catching fish or getting hits and so on. From memory we had them rigged up with 6’’ OSP DoLive Sticks because they so often well on this particular spot and of the conditions we would fish it in, but why was one lad not getting any sign of fish but the rest were? I would always suggest that a bunch of anglers are all going to fish the same lure in subtly different ways anyway, so what the hell was going on?


It wasn’t me who worked out what the problem was, for I must give full credit to the guy I work with over in Ireland here - John Quinlan. He also happens to be one hell of a fly angler and I would argue that leader diameters can make so much difference in so many fly fishing situations. I am not saying they don’t in bass fishing, but surely the presentation of a size 18 dry fly on top of achingly clear water is a bit different to punching metals into a raging dollop of surf, and so on. Anyway, John and I were trying to work out why one lad wasn’t catching when our four guys were fishing fairly close together and were all using similar methods. The lightbulb went off in John’s head and he changed the lads’ leader from I think it was 20lb over to 15lb - and the angler started catching fish straight away, which of course says to me that sometimes the diameter of one’s leader can make a difference to our catch rates.


Now the problem is always going to be that quoting leader strengths is actually pretty meaningless, because one tackle company’s 20lb fluorocarbon is a quoted diameter which could be a completely different breaking strain for the same diameter on another spool of line - and on and on and on! What does 20lb or 30lb or whatever actually mean when it comes to leader material, and are the quoted diameters actually true anyway? Well I don’t know the answer to either of those questions, but I do know the leaders I use the most, and I must therefore base my findings as such on those lines.


I do know that our client would have initially had a 20lb Sufix Super 21 FC fluoro leader on. Although this stuff is actually a fluoro mainline, I have used Sufix Super 21 FC a lot as leader material over the last few years and I think it works really well - and the 20lb is quoted as having a diameter of 0.40mm. So John Quinlan would have removed that 0.40mm leader and replaced it with a Sufix Super 21 FC leader again, but this time in the 15lb breaking strain, quoted as having a 0.35mm diameter. Go looking at various websites from the US and Europe and so on and you might find different specs to these - and yes, the obvious bloody word is always going to be why - but those are the figures I have on the couple of spools of Sufix Super 21 FC I have here so it’s easier for me to go by what I know. Back in my bait days I was always working on a 0.35mm monofilament mainline as being a quoted 15lb breaking strain, a 0.40mm being 20lb, a 0.50mm being 30lb, and so on, so whatever the Sufix Super 21 FC does actually break at on a line machine which doesn’t ever mean very much out in the real fishing world, I do know that John changing the guy’s leader to a thinner one made the difference on that particular session.


Another fluoro leader that I have come to seriously like and trust is the Varivas Hard Top fluorocarbon, and I also like how it doesn’t cost that much for what feels and performs like a proper leader material. The figures on the actual spools are diameter and #PE number, so my breaking strains for this line are via the Veals Mail Order website and what they quote. My go-to leader in this stuff would be the 0.370mm/#5, which Veals say has a 20lb breaking strain, and already you can see that we have a difference here - IF all these infernal figures are to be believed. Buy what is referred to as a 20lb fluoro leader which I reckon is probably a fairly standard setup for a lot of lure anglers and with the Sufix Super 21 FC you have a 0.40mm line, whereas it’s 0.370mm with this Varivas Hard Top. Drop to a 15lb/#4 leader with the Varivas and you’re looking at a pretty thin 0.33mm. I also really like the slightly thicker 0.405mm/#6 (25lb from the Veals website) and 0.47mm/#8 (30lb from the Veals website) for when the fishing gets that bit more rough and tumble, and I have caught bass on both leaders in conditions where I don’t personally believe that a thicker and therefore tougher leader is remotely putting them off.


I can’t prove it, but I do think the Varivas Hard Top leader material takes a bit more of a battering than the Sufix Super 21 FC, but then comparisons are perhaps a tad unfair because the Sufix stuff never purports to be a leader material. I stumbled upon this Sufix Super 21 FC fluoro mainline, decided to try it for leaders, and I found that it works really well (albeit it seems harder to track down these days), but I do like how the Varivas Hard Top - which does purport to be leader material - is a bit stiffer and I think more robust. Obviously you have those “top of the tree” and not remotely cheap fluoro leaders such as Seaguar and Sufix Invisiline, but as much as I have fished with and do hugely like the Sufix Invisiline fluorocarbon, for bass fishing I change my leaders a fair amount anyway and I can’t recall a much pricier leader making a discernible difference.

So there you go. I started this blog post talking about a specific session where the thickness of a leader seemed to make all the difference, and I have ended up once again tying myself in knots over different tackle companies and how they quote diameters and breaking strains and what have you. Do you buy your leader material on quoted breaking strain alone, and do you take any notice at all of the diameter? When you and I fish with say a 15lb fluoro leader (because it says so on the packet), are we using two somewhat different diameter lines? I have a 0.235mm Seaguar Saiko Stiff fluorocarbon from Yuki here for example that is quoted at a 15lb breaking strain. I refer you back to a blog post here from the other day, and I wonder if us fishing with different leaders could have had something to do with it as well? Monday morning and my brain is still bouncing away - welcome to my head!

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