On Mar 21, 4:44 pm, "rb608" wrote:
On Mar 21, 9:59 am, wrote:

Or telling me that the rod action affects what size fly you can cast,
when it has absolutely nothing to do with it?

On this, I must respectfully disagree. If I may use one of Sir
a Isaac's favorite equations, F=ma, it's clear that fast action rods
and
slow action rods have different capacities for the acceleration
component of that equation, and thus have a mathematical difference in
the force they can generate with a constant mass, or a different mass
with a constant force. That difference can manifest itself in either
the fly characteristics or distance cast; but there *will* be a non-
zero difference.

Joe F.

Firstly, rods don´t accelerate anything, casters do. The thing which
is accelerated is the line, the line carries the fly. Rod action
affects how much line speed may be attained, but it is the line which
carries the fly.

There is a slight difference in the amount of weight which a fast
moving line can carry, as opposed to a slow moving line, OF THE SAME
WEIGHT, but this is in fact quite minimal, as it is primarily
dependent on the basic carrying capability of the moving line mass.

There are also quite precise limits to what a line can carry at all.
Regardless of how fast you manage to accelerate say a standard #3
weight line, ( using a rod) it will not carry more than a certain
amount of weight, ( or a bushy fluid resistant fly, )the weight it can
carry ( or the fluid resistance it can overcome) is directly
proportional to the line mass which is actually pulling the fly along
behind it by unrolling. This may also be roughly expressed in grains
per foot ( ignoring the taper etc). The relationship of fly weight
( and/or fluid resistance if known) which the line will carry at all
may be shown on a graph of grains per foot/fly weight.

So although I would prefer to qualify it exactly, I don´t disagree
with you there about the difference being non-zero.It is however
negligible. There are some measurements on this in various studies,
but that would take us too far away from the present subject matter,
and merely confuse the issue.

The difference which accrues by using a shorter line of the same mass
is however very considerable. Regardless of the rod used. The shorter
line OF THE SAME WEIGHT, will carry heavier flies faster and further.
It has more grains per foot, it offers less fluid resistance than a
longer line of the same weight, and it is also a great deal easier to
load the rod properly with it. Something very many casters have severe
problems with.

This is the basic point here.

TL
MC