Or it just keeps you out of the grass!Originally posted by Fly Ty R:
I have a 10' 9wt that works great with a heavy sinking line (only because it's a slow action rod).
Think about physics (ahhhhhh, bad high school memories!!!):
A longer rod means a longer arc with which you are propelling the line. The larger the arc, the farther you are able to force the line into moving forward. That is why casting far with a 2-handed 16' spey rod is easier than a 9' single-handed rod, though a little heavier.
Here are a few numbers to completely scare everyone !!:
With a 9-ft rod (taking your body out of the equation), if you were to swing the rod in a cast of 360 degrees, the length of the circumference of the circle the rod tip travels would be approximately
With a 16-ft rod, the rod tip would travel (16x2x3.1415926)= 100.53ft.
But, we don't cast in circles (unless you want to look like me and be an idiot out there), so we have to divide that number by about 4 (as a typical cast moves the rod tip about 1/4 the length of the entire circumference). So, a 9ft rod propels the line at the rod tip
(56.54/4) = 14.13 ft with each cast,
while the 16ft rod propels the line at the rod tip (100.53/4) = 25.13ft with each cast.
You are getting almost twice as much force (distance) with each cast of a 16ft rod as you are with a 9ft rod. Simple math!!
For fun, let's do the difference between a Lefty's 9ft Temple Forks rod and a Bob Pop's 10.5ft St Croix rod.
Lefty's rod = 14.13ft per cast (as we found before)
Bob's rod = ((10.5x2x3.1415926)/4) = 16.49ft per cast
You would think that the 1.5ft added length of Bob's rod would equal 1.5ft of added length to the casting stroke. But, look at the numbers:
16.49ft-14.13ft = 2.3ft, not 1.5ft.
The difference between the rods in the first example is
25.13ft-14.13ft = 11ft, not 7ft.
However, the difference between the actual rod lengths and the casting arcs is not directly proportional. In a nutshell, the longer the rod, the more proportional casting arc you will get. Each added foot of length to the rod will give you more than one foot of arc to the cast, and that "more than one foot" variable increases with each increase in the rod length, if that makes any sense at all. So, in theory, we should all be casting 100ft rods (if they could make them light enough).
Pretty cool whacky stuff!