PLEASE NOTE: In order to post on the Board you need to have registered. To register please email paul@sexyloops.com including your real name and username. Registration takes less than 24hrs, unless Paul is fishing deep in the jungle!

Maximum Rod Bend

Moderators: Paul Arden, Bernd Ziesche, Lasse Karlsson

User avatar
Bernd Ziesche
Posts: 3436
Joined: Wed Jan 09, 2013 10:01 pm
Answers: 0
Location: Whereever the fish are!
Contact:

Re: Maximum Rod Bend

#71

Post by Bernd Ziesche »

Mangrove Cuckoo wrote: Fri Jan 15, 2021 2:50 pm But then, again as Bernd has pointed out, there is the angular relationship between the line and the stripper guide. It gets a bit curious for me at this point. It seems "hauling" is not optimized until the stripper guide is perpendicular, or beyond. And the guide could have gotten there via rotation, translation, or both. And... perpendicular to what: the ground or the line hand
Hi Gary,
lots of well put assumptions in your post!
The problem with modeling fly casting is, that it (the fly casting) is too variable depending on all our different fishing situations.
The haul can be done in many different ways.
If we want the line to run as fast as possible thru the guides, I believe it's effective to move the line hand in one way and the stripping guy almost opposite. Almost, because on one hand it's great to use the rotational speed (angular velocity) we can create for the stripping guide via rod hand and on other hand this requires having to live with more friction between the first guide and the line as when hauling exactly parallel down the rod.
Which technique I prefer depends on what exactly I am after. For sure it's worth playing with both.
I studied the different hauling techniques across many participants in the WC. Made a lot of videos. Fair to summarize there are a) different techniques between the fc and the bc for one caster as well as b) differences from caster to caster.
Of course in the WC we often also have to deal with different winds from caster to caster making it hard to compare.
Imagine this:
Caster 1 feeds his line hand far back close to the first guide in his back cast. That may lead to a lot of line having to be straighten outside the tip.
Caster 2 feeds his line hand less far back having less line outside the tip for a while. Both are holding their line at the same point.
Now you may say caster 1 will have more distance to speed up his line hand on the next fc, but it's not that simple. Caster 2 may slide his rod forward coming from a lower tip position only to then have additinol line slipping out the tip while pulling on the rod-leg by lifting the tip. Both may end up in a similiar set up to start the fc.
There are so many details one can work with, I don't see any model including all this giving an easy answer to what's best in general.
Regards
Bernd
http://www.first-cast.de
The first cast is always the best cast.
User avatar
gordonjudd
Posts: 1858
Joined: Sat Jan 19, 2013 11:36 pm
Answers: 0
Location: Southern California

Re: Maximum Rod Bend

#72

Post by gordonjudd »

The record data I use correspond to the speed relative to the stripping guide, Gordy can confirm if I fool myself or not on this point.
Merlin,
The primary constraint in looking at the relative velocities is that the length of line from the hauling hand to the fly remains constant.

Thus since the length of line from the first stripping guide to the tip follows the rod the assumption is that the distance from the hauling hand to the first guide+the line length from the first guide to the tip + the length of line from the tip to the fly is constant. That means a plus distance change from the hauling hand to the first stripping guide will produce the same distance change (it will get shorter) in the length of line from the tip top to the fly.

The net fly speed will equal the tip speed plus the haul speed. The haul speed can thus be calculated by taking the derivative of the length of line from the tip top to the fly or the derivative of the distance from the first stripping guide to the fly. That equal speed relationship was verified in one of Lasses' casts on the old board where he had placed markers on the tip top and the line at his hauling hand.

In that cast of Paul's the haul speed was calculated by taking the derivative of the distance from his haul hand to the first stripping guide. The location of the stripping guide was calculated by assuming there was no appreciable bending in the rod up to to the first guide so its nominal position could be determined by the angle of the butt of the rod and a fixed distance from his rod hand to the stripping guide. That assumption was approximate since there would have been some curve in the rod up to the first guide, but I think the resulting distance error would be quite small.

As Grunde noted years ago, it is important to look at the distance change from the stripping guide to the haul hand rather than just the speed of haul hand or the separation speed of the hands to compute the haul speed since the rotation of the rod can have a big effect on the line distance change. That is especially true on the back cast where most of the distance change is produced by the rod rotation and thus the peak haul speed invariably coincides with MAV on the back cast. Bernd showed a great example of how much the rod rotation impacts the distance from the haul hand to the first guide on the old board.

Gordy
User avatar
Bernd Ziesche
Posts: 3436
Joined: Wed Jan 09, 2013 10:01 pm
Answers: 0
Location: Whereever the fish are!
Contact:

Re: Maximum Rod Bend

#73

Post by Bernd Ziesche »

Good posting, Gordy!
That makes all sense to me.
Thanks.
http://www.first-cast.de
The first cast is always the best cast.
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Re: Maximum Rod Bend

#74

Post by Merlin »

Thanks a lot Gordy for reminding us important considerations for the haul.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
User avatar
gordonjudd
Posts: 1858
Joined: Sat Jan 19, 2013 11:36 pm
Answers: 0
Location: Southern California

Q

#75

Post by gordonjudd »

I don't think we can for example match max possible line speed of the line thru the guides and max tip speed to happen at the same time.
Does that make sense to you?
Bernd,
I don't see why you could not do just that since it comes down to a matter of timing between the actions of the two hands.

Even better, I would think that matching the max haul acceleration with the maximum tip speed of the rod tip so you would apply the peak force from the haul over a maximum distance would make sense from a work energy standpoint.

That said, elite distance casters seem to reach their max haul acceleration well before the tip is moving at its fastest, so there must be some more complicating factors involved than just applying a force over a distance in terms of achieving the maximum casting distance. I have always thought that good casters self-optimize their technique so it seems that there is a wide variation in the relative timing of the max haul velocity they use for their particular style.

I imagine you saw a range of haul timings in your WC videos. It would be interesting to get see the relative haul timing elite casters use in their distance casts. The release timing is another factor that seems to vary from caster to caster.

Merlin might have an idea of how the tension added with the haul hand impacts the speed of the loop as it is being formed. That could be an important factor on the ultimate propagation speed of the loop going down the line in addition to a simple superposition of the velocities that are measured in a high speed video.

Here is an example of the measured speed of the line moving through the first stripping guide compared to the measured angular velocity of one of Bruce Richards casts that was made by Noel Perkins years ago. The line speed was determined by using a Hall effect sensor near the first stripping guide so was a direct measurement of haul speed rather than the derivative of digitized distances from a high speed video. Note that the rod speed shown in that graph is for the angular velocity not tip speed. The maximum tip speed would occur a bit before RSP1 as did the max haul speed.
Image

This is a good example where the max haul speed coincided with the the maximum tip speed, so indeed it is possible to achieve the timing you asked about.

Gordy
User avatar
Paul Arden
Site Admin
Posts: 19528
Joined: Thu Jan 03, 2013 11:20 am
Answers: 2
Location: Belum Rainforest
Contact:

Re: Maximum Rod Bend

#76

Post by Paul Arden »

Hi Gordy,

When I asked Bruce about the haul analyser he said that they couldn’t haul too quickly/aggressively otherwise it wouldn’t read properly. I think on these shorter casts we often haul to or even through RSP.

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Re: Maximum Rod Bend

#77

Post by Merlin »

Even better, I would think that matching the max haul acceleration with the maximum tip speed of the rod tip so you would apply the peak force from the haul over a maximum distance would make sense from a work energy standpoint.
Merlin might have an idea of how the tension added with the haul hand impacts the speed of the loop as it is being formed.
Hi Gordy

If you place peak haul acceleration with maximum tip speed then peak haul velocity occurs somewhere during loop shaping and the beginning of line release. You might end up with a pullback right from the start instead of increasing launch speed significantly. I am unfortunately unable to estimate what can happen.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
User avatar
Paul Arden
Site Admin
Posts: 19528
Joined: Thu Jan 03, 2013 11:20 am
Answers: 2
Location: Belum Rainforest
Contact:

Re: Maximum Rod Bend

#78

Post by Paul Arden »

Is it possible to accelerate the haul post RSP? Wouldn’t the haul retard the tip? I’m thinking if you continually accelerate the line, say you had especially long arms, wouldn’t the line simply pull all the way through the rod while maintaining a bend in the tip?

This sort of stuff keeps me awake at night.

Thanks,
Paul
It's an exploration; bring a flyrod.

Flycasting Definitions
User avatar
Lasse Karlsson
Posts: 5757
Joined: Wed Jan 09, 2013 9:40 pm
Answers: 0
Location: There, and back again
Contact:

Re: Maximum Rod Bend

#79

Post by Lasse Karlsson »

So thats why you sleep so good 😉

Cheers
Lasse
Your friendly neighbourhood flyslinger

Flycasting, so simple that instructors need to make it complicated since 1685

Got a Q++ at casting school, wearing shorts ;)
User avatar
gordonjudd
Posts: 1858
Joined: Sat Jan 19, 2013 11:36 pm
Answers: 0
Location: Southern California

Re: Maximum Rod Bend

#80

Post by gordonjudd »

I think on these shorter casts we often haul to or even through RSP.
Paul,

Does that imply that the longer the cast the earlier the haul should be?

Gordy
Post Reply

Return to “Teaching”