Rod bend vs rod unload

[VGB]

Sounds like a universal truth must include “it depends”

[Lasse Karlsson]

Always the outlier that wants it hard

[Walter]

Hi Graeme,

A side note – I find that stiffer rods also “feel lighter”. The Broomstick, which is a heavy rod, feels extremely light when casting. No doubt this is because a bendy rod allows us to apply more force (Gordy calculated it can allow us to double our input). If we double our input we are doubling our effort and hence the heavy feeling.

Cheers, Paul

Also, the bend is a resistance against your force, if it bends less, less resistance, feels lighter, you are moving the whole rod from the get go. Untill you try and stop it and your elbow goes pop....

Cheers
Lasse

Same here. It feels heavier than a fly rod for the first tiny bit (start up inertia?), then lighter for the rest of the stroke when it gets moving, then the elbow goes pop!

Self decelerating doesn’t seem to apply to broomsticks.

[VGB]

Probably worth mentioning that no criticism of the trial is intended. It was designed to look at sequencing not distance casting.

[Graeme H]

Hi Graeme,

A side note – I find that stiffer rods also “feel lighter”. The Broomstick, which is a heavy rod, feels extremely light when casting. No doubt this is because a bendy rod allows us to apply more force (Gordy calculated it can allow us to double our input). If we double our input we are doubling our effort and hence the heavy feeling.

Cheers, Paul

Sorry Paul, but this logic doesn't make sense to me.

I could possibly agree if it was said that the stiffer rod needs a smaller casting arc to deliver an appropriate SLP than a soft rod would, so that the force being applied is done so over a shorter duration. Perhaps it might "feel light" because there's a smaller movement being used?

Being able to apply more force doesn't mean we must apply more force. The line only needs to reach a given distance, and we do that by accelerating it (using force applied by us). Using more force will accelerate the line more so it has more velocity at launch. But all the good casters I know won't apply more force than required to reach that velocity.

We don't double our input if we are only attempting to deliver a given velocity, so by the logic proposed, we'd need only need a bendy rod when we want maximum distance (i.e. maximum force). At all other distances, the bendy rod should mean less effort to put the same velocity into the line. (Bendy rod = more force delivered, so same force delivered = less effort by the hand.)

Torque is measured in Newton Metres (or foot pounds in the US). That's a force multiplied by the distance of the mass from the point of rotation. A long rod has more distance, and a stiffer rod keeps that distance further away from the pivot point (at say MCL). By that logic, a stiff rod should feel harder to rotate (or stop) than a soft rod, and a long rod should feel harder to rotate (and stop) than a short rod.

In my own experience, I find this last paragraph to be the case, especially in the higher line weights. Stiff 9' rods are harder on my arm than soft 9' rods, and 8' rods are easier on my arm than 9' rods. Soft 8' rods are fantastic! Stiffer rods feel heavy to me (and it's why I like the HT10 - it's not a broomstick.)

Cheers,
Graeme

[Paul Arden]

Hi Graeme,

Think of it this way. Pushing a feather or pushing a truck. You can’t apply the same force to the feather because all the work is done in moving your body (and a little bit to the feather). With the truck however steam can come out of your ears just getting it rolling.

Same thing applies IMO to rods but for slightly different reason. In the case of the non bendy rod all we can move is our body, rod and line. These are all very light (casting a broomstick shows us this). Stick a bendy rod in between and we can apply more force because the bendy rod stores it.

In both cases stroke length and casting arc are limited to our maximum reach. But I’m not even sure that is important.

Cheers, Paul

[Paul Arden]

About 20 years ago I taped a rod ring to a broomstick. A real broomstick. And tried to cast it. Irrespective of the challenges involved the feel element is what surprised me. Alejandro built an almost rigid fly rod for experimenting. So a lighter rod but still a rigid one. The feel is the same.

Cheers, Paul

[Graeme H]

Hi Paul,

You can indeed apply the same force to the feather and the truck. The feather accelerates quickly while the truck accelerates slowly. That is, F=ma.

Put another way, if you apply a little bit of force to a feather, you can make it reach your maximum arm speed without even noticing the feather is in you hand. Apply the very same force to the truck and it'll laugh at you.

Cheers,
Graeme

[Graeme H]

About 20 years ago I taped a rod ring to a broomstick. A real broomstick. And tried to cast it. Irrespective of the challenges involved the feel element is what surprised me. Alejandro built an almost rigid fly rod for experimenting. So a lighter rod but still a rigid one. The feel is the same.

Cheers, Paul

Now put a full 12 wt line on them and cast it. A 6' stiff rod will be easier to rotate than a 12' stiff rod, even if the rods are the same weight (mass) and that mass is distributed proportionally the same. With a lot of mass (the fly line) attached to the end of the rod, the cast should feel different (even if the rods "feel" the same).

That's MOI (moment of inertia) and it's the thing the "pundits" call "swing weight".

Cheers,
Graeme

[Paul Arden]

Hi Graeme,

I disagree. You can’t apply the same force to the feather because you can’t accelerate it quickly enough. Not unless you have the hand speed of superman. When I lift an 80KG weight off the floor I do more work than I can ever do when standing up without the weight.

I don’t disagree with you on the length of the rod. The longer the lever the more difficult it is to rotate.

Cheers, Paul