Line configuration affect on rod

[John Waters]

I think Gordy explained it quite well a few years ago, that the softer rod allows us to put more force in (to a given arc). This in turn alters our feeling of weight. His calculations at the time were that a flexible rod compared to a broomstick allowed us to double the amount of force we can input.

It’s a very easy test to do. We know it’s also happening in the world at large, because many casters use heavier lines than the rod suggests, but they could equally use softer rods to get the same feeling of weight with a given line that they want or expect.

A six weight line on a two weight rod will feel very heavy. But put that line on a 12WT rod and it will feel very light. This is despite the 12WT rod being much heavier than the 2WT rod and the flyline being the same in both instances.

Cheers, Paul

Hi Paul/Gordy,

I don't understand why soft rods allow more force to be applied by the caster?

John

[Paul Arden]

Sorry, let me explain my understanding of that, John. I don’t mean a soft rod, I mean a rod that is softer than a rigid lever. Ie one that bends. A very soft rod might prevent us putting in as much force because we run out of rotation angle.

In the case of casting a bendy vs rigid lever within a given angle change, some of our force is going into bending the rod. Let’s just say half of it.

If I move my hand from a to b and compare it to moving from a to b while pulling a resistance band, the resistance band requires us to use more force.

Having a very stretchy band doesn’t allow us to put in as much force as a stiffer band. But given no resistance band at all, ie a rigid lever, and we have no rod loading. This is why casting a broomstick feels incredibly “light”.

Cheers, Paul

[Merlin]

I think the statement was about the force applied to the line, not the one from the caster. I shall check that point hopefully.

Merlin

[gordonjudd]

I don't understand why soft rods allow more force to be applied by the caster?

John,
It is a result of the overshoot in the deflection of the rod as it reacts to an acceleration input from the caster.

Here is an explanation given on the old board.
https://sexyloops.co.uk/archivedboard/v ... 48#p216048

As Grunde explained, "So "the spring" allow for a large force for a longer time, at lower rotational velocity, in a sense it act as a gear box."

Merlin, can best explain the details of his finger/spring/marble SHO model that results in the nominal factor of two force increase associated with a flexible rod.

I think the statement was about the force applied to the line, not the one from the caster. I shall check that point hopefully.

Merlin,
I would think the caster would have to apply more torque to the butt of the rod to produce the higher force on the line.
Gordy

[Merlin]

I confirm, this is an acceleration issue of the line, not a caster’s force one. I think you are speaking about the line feel, Paul. I mostly feel the MOI of the rod.

Merlin

[Lasse Karlsson]

Most fishermen just use the heavier line to propel the size of flies they really want to fish, and go by the arbitrary number on the rod to say they fish light.

With similar outlay the 6 weight line feels equally heavy on both the stiff and the soft rod, the rods feel different. Depends on what you feel for Also the rod someone wrote 12 on most likely weighs 3 times as much as the one someone scribbled 2 on, makes it difficult to asses the 10-15 grams of flyline being moved around outside the tip for most fishermen...

Cheers
Lasse

[Paul Arden]

I think you are speaking about the line feel, Paul. I mostly feel the MOI of the rod.

I have no idea how you can tell them apart, since whatever we feel is transmitted to the hand via the cork.

My teaching suggesting to “feel for the weight of the line” simply has the effect normally of slowing down the beginning of the stroke. I don’t think it’s actually possible to separate line from rod feel, since it’s all a connected system.

Cheers, Paul