SLP

[Bernd Ziesche]

Usually the broomstick is short and with haul and translation you can still get OK loops.

Hello Torsten,
Alejandro, Aitor, Cesar and me all agreed to never have seen any tighter loops coming with the closest to straight fly-leg in addition as those I shaped with Alejandro's very heavy (almost zero bending) 9 feet graphite "broomstick". Aitor made a slomo proof for those my loops. Let me add, that this was me casting a broomstick for a first time ever. There was room for improvement (not in terms of a smaller loop though), if only I would have trained with that stick.
"Ok loops" doesn't reflect what's possible ime.

But for the same length it's less efficient, like e.g. Grunde and Tobias have shown. First because the line velocity will be smaller and second the tip path is curved.

Efficiency needs to be adressed in my point of view. Efficient in what exactly?

Tobias started his investigation, because he had a missunderstanding, when reading some postings here on SL. He thought, some SL users were saying, that rod flexibility castingwise only has disadvantages and wasn't needed. But to my best knowledge no one ever said that.
Based on this Tobias wanted to proof this statement to be wrong. For that he set parameters like this:

- zero mass for the broomstick and (flexible) fly rod
- same (100 degree) arc for both tools
- zero rod hand path for both (rotation only)
- tip path post RSP1 fly rod was left out
- the decelerational fraction of the arc for the broomstick was left out, too
- angular velocity was put the same for both rods
- the fly line to be accelerated was put constantly straight
- tip path for the flexible rod RSP0 to RSP1 was put straight

The efficiency he calculated was not representing any fly cast, but only reflecting on the energy transfer fly rod/broomstick to fly line.
A fly cast is about putting my fly to the target, usually a fish. If I fail to hit the target, I most likely will have to repeat the cast. Thus I spend twice the energy to hit the target. In other words: If my cast isn't effective at all, then efficiency seen for the purpose of my cast goes down the drain. In fact it's not worth comparing it at all.
In my opinion there is a very little sense in calculating efficiency for the cast without including loop shape, line speed and direction until the fly hits the target. It's great to compare line speed, but line velocity is what counts much more as you know better than me. When casting against wind, I would choose the tight loop and straightest possible fly-leg in low speed over the medium loop with a more convex fly-leg in high speed. This is based on my real fishing life experience.
Back to Tobias his investigation. No one I know would cast a broomstick with a straight as possible rod hand path (or even worse: rotation only) and a relatively wide arc. Instead one would add a rod hand lift at both sides of the stroke and keep the arc as small as possible. This would make for a much better fly cast - more effective and more efficient, too.
If a broomstick would not have any mass, I would take it castingwise (of course only castingwise) in some situations. No doubt we would see brilliant loops going pretty far. It would be a strong weapon in heavy winds.
Compared to that the flexible rod will open the loop front more and the cast imo will automatically loose efficency and often be less effective in fighting wind due to that.
Reality however is, that we have ZERO use for a none flexible stick, because it has too much mass, because it asks for a high level of force application within a small arc, because it asks for a tricky rod hand path, because we need some arc for deceleration, because we need high force to decelerate it and so on.
Taking the way Tobias made his calculations, a pretty flexible rod would be more efficient as a pretty stiff one as he concludes. That is because tip path would be closer to straight with the more flexible rod (if not Tobias would have set a straight path RSP0 to RSP1 for casting his RPL+ anyway instead of using a realistic tip path).
The truth however we see in the WC (stiffer rods in distance). The reality is, that it all depends on the many key factors being relevant in every single situation (tackle set up, type of cast, outside conditions and the abilty of the caster to list a few).
Here is what Tobias said, when having been questioned about his choice of tip path for the broomstick:
"There is no single clue, that the broomstick could be cast more efficient when applying different movements to it."
Well, this is wrong and was already been proven many times by slow motion studies.

If I would want to prove Tobias his findings to be wrong, I could set parameters like this:
- huge force applied for both tools
- tip path for a very flexible rod drops too much and a tailing kills the unrolling
- rod hand path adjusted for the broomstick to achieve a straight tip path and a very tight loop drives the fly to the target
Would there be a point in this?
Not at all. Fly casting is not about a sterilized model. We only ever will cast in the real world. If a model does not fit, it has failed.
Regards
Bernd
P.s.: No offense against Tobias his effort (which I appreciate a lot) or anyone intended. Just being straight in how it looks to me.

[Lasse Karlsson]

I didn’t know you were a GT expert Lasse

The riffle didn’t fare too well in the movie.

Cheers, Paul

I sure as a dead dodo am not , just what I have been told by people. My first GT to hand baffled my friend and the guide by turning around on the way away and taking my fly anyway. thats why I know there's hope for you too mate

Depends on which movie you think of

Cheers
Lasse

[Paul Arden]

A Fistful of Clousers.

Turning around is something I try not to experience. But on occasion I have tried it

It might come down to what we are more used to handling. I watxhed Haysie try to take the bottle caps of floating beer bottles with spinning tackle.

Cheers, Paul

[Stoatstail50]

No one I know would cast a broomstick with a straight as possible rod hand path (or even worse: rotation only) and a relatively wide arc. Instead one would add a rod hand lift at both sides of the stroke and keep the arc as small as possible. This would make for a much better fly cast - more effective and more efficient, too.

Agree that

All casts pretty much, even with bendy rods, are mediated by the hand path as part of the mix.

A curvilinear hand path is required to counter rotation of the broomstick. The longer the stick and the wider the arc, the more extreme the curvature of the hand path and the less easy it is to input force at the butt and manage force vectors at the tip.

This is also true for a really bendy rod or one of the old parabolics that Brian was describing. That, for me, was a really eccentric hand path…very odd.

[Lasse Karlsson]

Need a longer broomstick...

[Torsten]

Well Bernd,

we had these discussion way before Tobias work here on this board. Because you mention the WC it seems to me that you're mixing up effectiveness and efficiency, the latter is low in the priority list for tournament casting IMHO, therefore is your example not applicable.
In general I've found Tobias work quite interesting, as far as I've understood it, he was comparing one on his casts to a rigid rod with the same mass distribution - I've checked not all his computations - but it seems to me plausible that a flexible rod could be more efficient for this case. I'm wondering why you want to "disprove" him with a set of unrealistic parameters, also in this case it's not applicable for me - I'm rather interested in efficiency for a typical fishing cast.

He has defined efficiency as rate between the work that the caster did and the kinetic energy of the tip and thus the line. I'm guessing I'd define this metric slightly different and would also include the unrolling of the line and the losses during this phase. I'm sure that Merlin did some research too.

Anyway, Grunde has summarized major functions of the flexible rod (regarding casting) here:
https://www.sexyloops.com/articles/rodcast.shtml

In addition to rod flexure providing stored energy, it also allows for a smooth application of power during the cast and it allows the tip to track straighter through the air (making for more efficient loops). A flexible rod also avoids the ILS issue of MAV and maximum tip speed occurring simultaneously, which could have ramifications for aiming.

Greetings,
Torsten

[Lasse Karlsson]

Hi Torsten

As far as I can see on Tobias' work, he has used an unusual large bend in the rod as base for his calculations. No one is saying a bendy rods isn't the most efficient, it's the amount of help in gives which seems to be disputed, with Tobias wanting around 50% of linespeed from flex and whip. In a hauled cast none the less. He used to have a youtube clip, much like Bernd's, with a rod stuck in the ground, line pulled back, and then released. Where most of us gets the fluff to around or just past the rod with a similar bend as when being cast just prior, Tobias got 17 meters. He did use a too large bend, but it was taken from a clip with the rod in a sidearm cast. Perspective makes the bend appear alot larger than it is, Tobias doesn't want to acknowledge that.

Cheers
Lasse

[gordonjudd]

Alejandro, Aitor, Cesar and me all agreed to never have seen any tighter loops coming with the closest to straight fly-leg in addition as those I shaped with Alejandro's very heavy (almost zero bending) 9 feet graphite "broomstick". Aitor made a slomo proof for those my loops.

Bernd,
Do you examples of the tip path you produced with a long broomstick rod? I would expect that it would have a pronounced convex path since the rod hand path could not adequately compensate for the non-bend of the rod as it was rotated to produce a straight line path.

Video could well prove me wrong about that assumption if you found you produced the "closest to straight fly leg" in your broomstick casts.

Gordy

[Stoatstail50]

I cast Alejandro’s broomstick too Gordy. The hand path isn’t totally dissimilar to the initial downward curvilinear period in the old Chris Korich vids that everyone dissected. That bits pretty easy. It gets tricky in the latter part of the stroke when the hand has to come back up again. There’s no counterflex so the loops are tight and after a minute or two it hurts like hell.

I’d be surprised if, on an E in E out basis, the broomstick was less efficient than a bendy rod, all other things being equal. Where the bend delivers is in mediating for the extreme hand path, which makes it easier to get E in in the first place…and it doesn’t hurt because a bendy rod “stops” over a longer period of time than a rigid one…which means less pain.

[Torsten]

Hi Lasse,

As far as I can see on Tobias' work, he has used an unusual large bend in the rod as base for his calculations. No one is saying a bendy rods isn't the most efficient, it's the amount of help in gives which seems to be disputed, with Tobias wanting around 50% of linespeed from flex and whip.

have to re-read this point; but I think this was the x-velocity of the tip only, because the vector is facing not in the direction of the line for the rigid rod it might be plausible. The simplification was a pure SLP for the flexible rod, sure you could argue that the bend gets then too large - but when you compare the ideal rigid to the ideal flexible rod, I think higher efficiency for the latter is reasonable for me and one major reason is the shape of the acceleration path.
You could outweight that by raising and lowering the hand, but this means then extra work for this movement.

Perspective makes the bend appear alot larger than it is, Tobias doesn't want to acknowledge that.

Sure, but I don't know if that would have any effect on the outcome, the assumption was a perfect SLP anyway.

Is a straighter tip path during acceleration is more or less efficient for you?

Greetings,
Torsten