I’ve found a nice knotted leader formula on a French blog, the fancier I know with respect to the maths involved. I’ve blogged about it earlier here, it’s in French.

The Fibonacci suite is an arithmetical succession of natural numbers such that (i) the first two are 0 and 1, (ii) each term following 1 is the sum of the two previous ones. Hence it goes like 0,1,1,2,3,5,8,13,21,… So the idea is to cut out of the sequence a series of numbers that will give the proportions for the leader: 1,2,3,5,8,13. So for example it would give 5,10,15,25,40,65 inches. Then comes the question of the diameter. The original author gives a formula (start FOR EXAMPLE with .45 then proceed taking a half and multiplying by the golden proportion, which is a clear case of delusional numerology) that nevertheless gives a reasonable series: .45 – .35 – .30 – .25 – .20 – .16 – .12

For those of you stuck with the imperial obscurities, I’m sorry. I can do inches, but I struggle with Xes, so diameters are in millimeters, like they should in a rational world. ^_^

I’ve used the formula and it worked well for fishing wets with a 4wt. Only, I’m too sloppy to make all these precise measures when I’m tying a leader, and since I do a lot of tailing loops, especially when lawn training, I destroy lots of leaders, so I tie them not infrequently, and I really don’t bother with precise measuring. I just go  for decreasing.

But if you want to impress the crowd with arcane details and esoteric theories, that Fibonacci stuff is good.

this mystical leader formula might be good, might be bad and frankly who cares…

to break it down simply leaders are about energy transmission and energy dissipation all through mass distribution.
as such, the butt part of the leader needs to continue the energy of the fly line through it’s mass, otherwise it’s either too heavy or too light. what this means is the butt diameter should be in relation to the size of the fly line tip used.
from there it’s easy to understand that a leader butt that’s appropriate for a 7wt will not be a good choice for a 4wt and vice-versa.
the article states that a leader should start at this or that diameter without even mentioning the line wt, the type of fishing, the species or flies cast.
it also tells us to change leader length according to the rod’s length ?! wtf…

these are signs of simply repeating someone else’s misunderstanding and lack of knowledge of the issue…

cheers,
marc

• oh boy, here you go again with that nice tone of yours.
but, as I really claim to master the rocket science of leaders, you’re obviously entitled to give me a run for my money.
let me nevertheless make a couple of points in my defense:
1. I don’t even endorse the method, I just find it fun to use Fibonacci to make a leader. you may have been deaf to the heavily ironic overtones of the post.
2. the very point of the method (the part I want to extract from this guy’s stuff) is just to provide a series of proportions for the segments of a leader, it tells you nothing about whether it’s increasing or decreasing length (starting from max diam), the basic length you want to use (hence the total length), and nothing either about the diam you want to start with.
3. the leader I build this way worked well with a 4wt for wets. I should probably have specified it (if I had any idea that someone was in peril of taking this humoristic piece as a gospel)

Now, pray tell me O wise one, if “what this means is the butt diameter should be in relation to the size of the fly line tip used”, is there somewhere a table of such a relation? I can’t seem to find one.

2. as a side effect i’m glad you took it personally ! although it obviously isn’t. the big ‘ole wtf negative tone goes out to the writer of the article and the ones who he copied his ‘leader science’ from before him, not you.
when i see crap i point it out so others don’t step in it.

butt diameter/line tip:
both materials will differ in mass from company to company and from model to model and type of material but start testing with butts between 2/3 to 3/4 the size of the line tip.

Charles Ritz had a much better, no-bullshit approach to leader design and basically is the roots for all good, modern tapered leader designs whether they’re home made or factory built. look it up.

• I always take it personally, that’s what diva do.

now, how on earth will I find the tip diam of my trusty GT140S WF6F, as a random example ? should I judge that by eye? are we again in one of those ‘nothing replaces experience’ situation?
isn’t stiffness of the leader material relevant also? I feel that at comparable diams, nylon is stiffer than a fly line. is that why you want to start at 2/3-3/4 and not 1?
I heard some boil the leader. is that related?

• use a caliper or your eyes (and a loupe). it’s better than nothing. even for a diva… :p
after testing, once you find the right diameter write it on the spool: ex- 0,55mm = ‘6wt butt’ or something similar.
be prepared to change this as you change brands and types…

stiffness might have an incidence for big heavy rods and say, salt water fishing but flexibility and mass are what’s more important for most fishing situations.
yes, the inherent stiffness of mono is why we step down to those proportions but once again, it’s all about mass.

boiling mono makes it more flexible, takes away coil ‘memory’ and allows it to stretch, a very important aspect in fishing as it makes for a much higher ‘effective breaking strength’.
boil water in a pan and cook the mono (not the spool !) for a minute or two. there’s no exact times, years of testing has shown that it doesn’t really matter.