The line kicks

When a fly line is cast without a leader it will kick. The caster loses his/her control over the fly line. If you doubt it stop reading now and try for yourself. …….. Ok, now you tried, and we can continue. The energy that usually propels the fly line, and straightens the leader, is still there, but now the energy has nowhere to go but back up the line, and the line kicks. Now, what happens when you cast a line with a leader? Voila, it doesn’t kick now. The energy in the line is now transferred (bleeds) into the leader. Of course, as all this is happening the energy of the cast dissipates because of the drag.

Enter physics

Moving mass (the fly line, leader and fly) is governed by a law of physics – the law of the conservation of momentum. It is a simple one, and for our discussion a useful one. When we cast a fly line and the loop starts to form, the rod leg of the line is stationary. The top/fly leg has all the momentum, but as it passes the apex of the loop and becomes the rod leg, it loses mass, but picks up speed. This increased speed is now dissipated by the drag (speed doubles – drag quadruples). At the end of the cast there needs to be just enough energy to turn over the leader and the fly. So, that energy needs to reach the fly. All explanations and theories of fly casting must be rooted in the laws of physics. If not, they are simply wrong.

Mr. Redfish
Mr. Redfish is caught with a heavy fly

Noticed the fly line speed up?

From the formula (p=mass * speed) it is easy to understand — when mass decreases speed must increase. You have probably noticed that the line sometimes speeds up at the end of your cast – well, pay close attention next time you cast, and you can see this happen. The energy of the cast is moved through the mass of the line, and it is obvious that the energy in the line must transfer over to the mass of the leader. That transfer works to our advantage if the mass of the leader’s butt end is about the mass of the terminal level tip of the fly line. If the diameter of the leader’s butt is approximately 70% of the level tip of the fly line, we are in the game. You noticed that I was writing about the mass of this and that, and suddenly I am using diameters. Well, the greater the diameter of the leader material the heavier it is (more mass). We have these diameters printed on the leader info sheet (if there is no such info don’t buy that leader), and the butt and fly line tip diameter are easy to measure with a micrometer (yes, I do that!). Therefore, it is now easier to use the diameters in our communication.

Angler’s leader butt is generally too small

I can guarantee that most fly anglers will use a leader where the butt diameter is too small, and does not match the tip of the fly line (70% is enough). There is simply insufficient diameter/mass in the leader butt to transfer the energy from the fly line. That is a sure way to lose energy, and then the leader does not have enough energy to turn over, and the fly lands on the top of the sorry pile of a leader. I know this well because I have been there. This is when the demon whispers into your ear – “son, that ultra-fast new fly rod is what you need.” Yes, yes, yes and you rush off and buy the ultra-fast ……. fly rod, but you still cast bird’s nests.  The road mostly untaken runs through coaching and practice. It is galling that such a simple remedy exists, i.e. just use a leader with enough diameter/mass in the butt section to turn over your leader and fly. However, folks generally do not understand this principle and suffer accordingly.

Running of the Bull Reds
Bull Red – when you pay attention you are rewarded.

As the energy rolls along the fly line to the leader, the leader is dissipating energy (as it speeds up, the drag increases). Now, by having a tapered leader you also immediately realize — as the mass decreases the speed must increase (law of conservation of momentum), and thus we have generated enough energy to turn over even a heavy fly. It’s now obvious that we can cast a small fly with a longer leader than we can cast a heavy fly. It follows that sometimes by just shortening your leader, you can now turn over that heavy fly causing you so much trouble on your last trip.

Enjoy it more

Baz with Mr. Red
Capt. Baz is certainly enjoying this red

There is no absolute need for you to understand the physics of fly casting to enjoy the sport. However, you certainly will enjoy your sport much better when your cast improves, when you can turn over big heavy flies by paying attention to the butt end of your leader.

Morale of the story

So, the morale of this story is always to use a leader, whose butt’s diameter is somewhere around 70% of the tip of the fly line. This will ensure optimal transfer of energy from your fly line to your leader, improving your cast, and ensuring turnover of heavier flies.


What to look for

A note on leader purchase. Leaders are sold in small packets where you will probably only see indicated the breaking strength, and perhaps some X designation (salt anglers do not care about the X denotation). However, the X designation is useful for trout fishermen for diameter, and relates to suppleness, and strength too. Armed with this new advice of matching the butt of the leader to your fly line, you should be looking for Length, Tippet Diameter, Butt Diameter, and Break Strength. If no such information is divulged, do not buy the leader. (see picture below)

One company’s great info sheet.

English consultant: My good retired neighbor Joe

More on leaders from my web book

https://everyjonahhasawhale.com/?page_id=1246

Here is a lecture on matching a fly line and a fly rod.

There are two properties to consider before casting any fly. First, the weight of the fly, and secondly, the air resistance (drag) of the fly. It took me a while to realize the weight of the fly is the driver/determinant of the choices of which line and rod that we should use. I have neither caught a fish that took my fly because it was so happy with the NRX rod I was using, nor has any fish shown particular excitement, one way or another, when I use this or that Amplitude line. Of course, it is better to have good equipment, but if you can’t cast the fly, the game is over. So, when you mull this over, I hope you will realize that the fly to use for the particular species you are going for is the first determinant of the tackle.

Let’s consider the weight of the fly. The heavier a fly gets the meatier fly lines you need to cast it. The mantra is — mass moves mass as simple as that, and everyone understands this simple truism. However, one of the most frequent questions I get here (Florida Panhandle) is, “Why can’t I cast that Clouser with my eight weight?” Then I answer, “Well, can I try?” Then do and find that this Clouser can’t be cast with the client’s eight weight, using the standard casting technique. The problem is that most casters haven’t mastered the casting technique needed to cast heavy rigs.

I have three possible solutions to this situation. First, I recommend a lighter Clouser for that rod size (less mass in fly). Secondly, I recommend a heavier line/rod combo for that specific Clouser (more mass in line). It is obvious — we must match the mass of a fly with the mass of the line. Thirdly, I can teach the Belgian cast. But guess what the clients do? They go and buy more gear of course. I know, I did the same until I learned to cast properly. However, you can’t buy a cast, see https://everyjonahhasawhale.com/?p=888

In the previous blog I described the technique (Belgian cast) used to cast heavy flies https://everyjonahhasawhale.com/?p=3188.

Now, consider the drag (air resistance) of a fly. It is a given that the drag will increase with the fly’s size. We can counter that only to a certain extent. We can increase the speed of the fly, however, but when the fly’s speed is doubled its drag will then quadruple.

You can see the trouble mounting. Big and heavy flies just aren’t easy to cast. That’s just simple physics, something which is immutable. Big fish love big flies – that is one of our mantras, too. So, we really can’t do much about the drag (except fishing at high altitudes). That leaves only the weight to be considered.

Bob's Banger
Bob’s Banger

This is Bob’s Banger. It is a great fly, and I love it. The question is — can we decrease its mass? The Banger weighs 0.073oz or 2.08gr.  Where is that mass, and do we need all of it? The mass is located in the long shank onto which the fly is built. The long shank has no other function. Because of the long lever the shank length is a disadvantage when fighting fish. Now the bulb should come on!

Plastic Tube - popper built on it
Plastic Tube – popper built on it

We can easily build the same fly on a light plastic tube. Tube flies are very simple to tie, and I find them easier to deal with. What about the hook? We use so called tube hooks for the job. Tube hooks have short shanks (advantageous), and we simply thread the leader through the tube and tie onto the hook. Then we pull the eye of the hook into the rear end of the fly where we sometimes have a piece of silicone tube (hook holder) snugly securing the hook in place.

The short shank hook
The short shank hook
Identical Bangers
The tube fly assembled – ready to go

It is not important to secure the hook, and the tube usually comes loose when you are fighting fish, and interestingly, rides up the leader. Thus, tube flies seem to be more durable. Furthermore, they don’t ever rust.

Identical Bangers
Identical Bangers

The long shank edition weighs in at 0.073oz, whereas the tube version weighs 0.044oz. In grams 2.085 vs. 1.24.

So, the answer to the first question — “Must big flies be so heavy?” — is equivocally no.

The answer to the second question — “Can the mass of a big fly be decreased?” — is yes.

I rest my case.


Tube flies have been around for a long time. They are extensively used in salmon fishing. I came across them in the salmon rivers of Iceland 30 years ago. Of course, the saltwater tubes are used here in the States, but they are not as well known as they should be.

English consultant: My good retired neighbor Joe

Fishing had been deemed essential by the Tallahassee Oracles (and it truly is) during the lockdown the of Florida beaches. So, Baz and I went fishing one glorious day. The weather was just great (disclaimer — whenever a fisherman begins a sentence with the bloody weather you know she/he in all likelihood got skunked), and the visibility into the water was fantastic. Even I could clearly see the fish. There were a lot of redfish and jack crevalle schools milling about. We just anchored the boat in such a way that we expected the jacks to swim on the outside of us, and they did, one school after the other. You just have to cast to those big badass fish, and when you spot them, the urge is immediately there. We decided to use a big popper called Bob’s Banger, which is only cast by folks with masochistic tendencies (sadomasochistic when we hook our company). These big and heavy poppers are a pain in the – wherever you like your pain best – to cast (how to cast big poppers – see at end). For the first school of fish we cast the fly in front of the fish as they bore down on us, but the line did spook them and that was that.

Bob's Banger
Bob’s Banger (4” long 10cm)

When anglers first see the jacks come in formation in two – three feet of water, they often just freeze. They just stare – eyes popping, mouth gaping, sphincters can go iffy, and they are totally unable to get off a cast. Those beginners who unexpectedly do get off a cast bungle it without fail. There is usually only one chance to deliver a decent cast to each school. The schools were coming thick and fast at us, and all the jacks swam the same way as you can see below. We decided to cast the popper straight out and have it waiting in the blue part you can see below. The rationale was to cast an unhurried long cast where we could strategically place the fly where we wanted it. That done, we just waited for the next school to come cruising.

Here come the Jacks
Here come the Jacks – tighten up those sphincters

This school of jacks showed up as predicted, and you can see the line that has just been biding its time. When the time was right the popper popped away, and some fish just ignored it, and swam under the line, but suddenly a bruiser in the 20-30 pound class swam under the fly. Suddenly the jack turned back and up, and came to the surface just in front of the popper, in precisely the same way a big salmon takes a fly on the surface. Baz and I both saw this magnificent take but it happened so quickly that it was impossible to catch in a photo.

Flyline laid out
Fly line laid out – red arrow on popper

I set the hook and the fight was on. Jacks simply take a very dim view on being hooked, and they are fast, strong, and mean, but not impossible to deal with. After a while the fish tired and I eased it towards the boat. Baz grabbed the leader and was ready with the net in the other hand. And presto — the fish broke off. He turned around and sternly asked “Jonaswhat was the pound strength of that leader?” (he knows that I sometimes just slap on whatever I happen to have in my pocket). Eyes downcast and somewhat sheepishly I murmured “maybe ten pound.” That answer just earned me THE LOOK.

Damn – in the doghouse again. But I managed to rescue my tattered standing, and finally pulled off a really long cast, with a backhand delivery, to hook a redfish that I managed to land; proof see below.

This blog is deficient if I do not honor the jacks with a picture. The jacks are a force to be reckoned with for sure, and here is a picture of one of them.

Jack Crevalle
Jack Crevalle – the Popper in its mouth

The jack crevalle is in the jack family with the GT (giant trevally). GTs get much more press, but are no more of a game fish than our crevalle.

https://en.wikipedia.org/wiki/Crevalle_jack

https://en.wikipedia.org/wiki/Giant_trevally

How to cast big and heavy air resistant flies

The Bob’s Banger in the first picture weighs in at 0.073oz or 2.08gr. So, it has considerable mass and a lot of drag, too, being 4 inches long (10cm). The considerations as to a fly’s “cast-ability” are its weight and its drag (air resistance). This fly is both very heavy and also has a lot of drag. I would advise using at least a ten-weight line or bigger if you have it for such a beast (mass moves mass). The leader that works best has the thickest butt you can find (again more mass in the leader – SA now makes a leader with 0.03” butt). Forget about a long leader, but instead shorten your leader to 7.5′. Now you are in the game, but if you try to cast this beast the “usual way” it will probably not go well. I advise you to open your loop and lob the popper out there. The cast I am referring to is the Belgian cast or the constant tension cast. Beware of casting videos where the teacher says “horizontal back – then up and over” for instance. If the line is horizontal and the caster points the rod straight back, all tension in the rod is gone and the fly will ricochet. Start the backcast horizontally, and when the rod tip is coming to the three a’clock position you start to bring the tip up. At that point, the heavy fly will swing up high – you come to the delivery position and go straight into the forward cast. And there should be no pause. Here is the best Belgian video I can find.

https://www.thecampflyfishingschool.com/pages/belgium-cast

Belgian cast's rod tip trajectory
Belgian cast’s rod tip trajectory

English consultant: My good retired neighbor Joe

The spectacle of spring and the arrival of the migratory birds make for a miraculous time in Iceland, where I was born and raised. Here in the Florida Panhandle there is really no winter, comparatively. However, there is a distinct spring. It is spring when the migratory birds travel through to destinations further north (robins, orioles, etc.), and the ruby throated hummers arrive and make their presence known. Most are migrating through, but some take up residence in my yard. Then in the fall the hummers migrate south to Central America. Their migratory routes can be along the coast west to Texas and then south through Mexico to reach Central America. They can also cross the Gulf of Mexico, and that is quite a feat because these small birds cannot land on water. They can travel via the Florida peninsula to Cuba, and then use the Caribbean islands to reach South America.

So, what is so special about these birds? First off they are so tiny – 3.75” long and weigh in at 0.11oz (9.5cm – 3.2g). Then there is the physiology. Their resting heart rate is 500 bpm, increasing to a whopping 1200 bpm when flying. Then there is the wing speed – the hummer can beat the wings 50-200times per second! The birds can hover in the air, ascend or descend straight up and down from that position, and fly backwards. To be able to accomplish that their brain has grown to about 4% of their weight, the largest of the bird brains, based on percent of body weight (human brains are a paltry 2%). For this rapid metabolism they need lots of energy. I take advantage of that and have feeders with a sugar solution ready, hung from the pergola from late March onward.

Ruby throated hummingbird (male)
Ruby throated hummingbird (male) – approaching feeder

Then I can sit back and enjoy the birds and sometimes I manage to take a photo of them that is in focus. To freeze them in the picture you need insanely fast shutter speeds, for instance, the featured image was shot at 1/3200 of a second and still one wing is blurry. They also can slow down their metabolism at night and enter into a state of torpor just to awaken the next morning for another day, like waking up from the dead. These pictures are of a male (the females are very similar without the red patch). When a male has found the feeders, he tries to defend them from all other males. Females get to drink, and I smell an ulterior motive.

Here I managed to get a picture of the bird with the tongue sticking out. Their tongue is very long, and they use it as a micro-pump to get the nectar.

The coloring of their feathers and the red throat are based on the iridescence of the feathers. Depending on the sunlight the color can be striking. And generally, the hummingbirds have an absolutely breathtaking display of colors, depending on the angle of light and the iridescence of the feathers. The bird seen perched on my fly rod has a commanding view of “his” feeders which he will defend from other males.

In these times of the plague I find it reassuring that there is a lot to cherish and be in awe of in nature around us that goes about its business, regardless of our worries. The hummers are certainly a booster to the daily dose of antidepressants. I certainly love those wonderful birds.

English consultant: My good retired neighbor Joe

https://en.wikipedia.org/wiki/Hummingbird

https://www.allaboutbirds.org/guide/Ruby-throated_Hummingbird

https://www.sibleyguides.com/2011/09/the-basics-of-iridescence-in-hummingbirds/