Bamboo Fly Rod Designand Analysis (RodDNA)
Presented by Chris Bogart

Purpose of Presentation
Familiarize Rodmakers with:John Bokstrom’s Controlled Modification
 Larry Tusoni’s RodDNA program

Demonstrate the capabilities ofRodDNAControlled Modification
First articulated by John Bokstrom


Minor insights by Letcher Lambuth

Starts with a satisfactory rod taper
Then characterizes that taper
Then allows the modification of thetaper (length, action, and line weight)
to known principles

Rod Characterization
Dimensions of 4 rods of similar action but
different lengths were plotted on graphpaper.
The slope of each these Rods was found bydrawing a line through the 10% and 60%
values of the taper length.
10% eliminates adjustments made at the tip 60% is where the action (slow to fast) of the rod
is revealedRod Graphs

Rod Plot
Rod Taper Plot
0.45

0.4

0.35

Rod Diameter

0.30.25

Rod Taper
Slope Factor Points
Slope Rise

0.2

0.15

0.1

0.05

00204060
Length in Inches

80100120

Characterization Findings - 1Rods of similar action but different
lengths and line weights had the same
slope or rise (.268”/100”).


Slope is expressed in inches of rise per 100inches.

Characterization Findings - 2
It was noted that the value of theslope rise lines at zero reflected the line
weight:9wt - .094
 8wt - .088
 6wt - .078
 5wt - .072
Characterization Findings - 3
When a nearly identical rod to the 5wt
but that had a slower action wascompared, the slope turned out to be.260”/100”.
Perception - Faster rods appear to havesteeper slope rises than slower rods.

Rod Action

Characterization Summary
The result of the characterization ofrod tapers are:Rods of identical action have identical slope
rises.
 The zero inch value of the slope rise
(regardless of what the taper actually has)determines line size.
 The action of the rod depends on the slope
rise.
Implementation
Need to first plot the rod taper
Find P1 - 10 % and P2 – 60% and draw slope and find rise per 100 inches – now called Rod
Action Value (RAV).
 Note value of rise at zero inches – now to be called Line
Weight Value (LWV)
Now find the rod taper factor by calculating RD/RV at 1%
increments of the taper RD – rod diameter
 RV – rise value
The resultant 101 (0 to 100%) rod taper factor data points
characterizes a specific taper independent of length.

Taper Modifications
Change the rod length
To change the line weight and keep action
same – increase the LWV by a value ofapproximately .005” - .006” and recalculate
the taper
To quicken a rod increase the RAV.003 change is barely detectable .010 is definitely noticeable.
 General rule – make shorter rods faster and longerrods slower.
Modified Taper
Generated from the rod taper factor
data points using the desired:
New length
 RAV
 LWVComputer Program
John Bokstrom’s original computer
program(s) were:Rod factor data points were painstakingly
calculated using manual methods.
 Each program was for one specific rodtaper.
 Had no modern graphical user interface(windows).
Current Effort: RodDNA
Capture the original concepts and provide auser friendly interface.
Expand program capabilities:
Ability to input new rod tapers.
 Include tapers taken at irregular intervals.
 No manual charting required.

Maintain a database of “favorite” tapers.
 Apply other modifications to a rod taper asdesired.
 Graphical plots of results.
RodDNA
Larry Tusoni has written it in Java –Will be able to run on Windows, Mac, Linux

Includes an initial Taper Database of 443
tapers and allow easy input new tapers
Includes an implementation of Garrison
stress curves calculations
Provides Graphical Plotting and Display of
selected single or multiple tapers (both stresscurves or dimensions)

RodDNA - continued
Performs Controlled Modification
Calculate ferrule sizes / section lengths/ tip top size
Taper conversion from Hex – Quad –Penta
Taper conversion for changing thenumber of sections in a rod

RodDNA - continued
Save taper extracts to local disk ornetwork
Import tapers exported from Wayne
Cattanach’s HEXROD or Joe Byrd’sRodmakers Database program
Sort tapers and save.
User can modify default values in fields

Garrison Rods: SelectedGarrison Rods: Dimension PlotGarrison Rods: Stress PlotGarrison Rods: Taper Values

Controlled Modification (CM)Can be done on any:
Existing taper in data base
 New taper inserted by user On any taper already generated using CMUser can quickly modify any taper
User can use CM to analyze andcharacterize tapers

CM – Taper Plot for 212E

CM Example: Garrison 212E
Original 212E CM Values
Length – 96”
 RAV – 0.270
 LWV – 0.077
Desired New Rod CM Values
Length – 90 (shorten rod to 7’ 6”)
 RAV – 0.272 (very slightly quicker)
 LWV – 0.072 (decrease in line wt. (6 to 5)CM Result: New 212E[1]CM: 212E versus 212E[1] StressesCM: 212E versus 212E[1] Dimensions

CM: 212E versus 212E[1] values

CM Result
A new rod (212E[1]) that closely
matches the original - but is entirely anew length, slightly faster action, andone line weight lighter.
The stress curves are the essentiallythe same!
All at the click of the mouseCM: Summary
CM provides a mathematically soundapproach by which existing tapers can be
modified to obtain a new taper with desired
characteristics.
CM characterizes the Rod’s DNA to generatea new rod based upon it.
CM is a transformation process (can goeither way and end up with the same result)Consistent Tapers
Tools allow the rodmaker to compare,modify, and perform taper conversions
in ways never possible before
RodDNA can provide the rodmakerwith the tools by which to develop a setof consistent tapers across ALL theirmodels, once they have determined therod action they desire.

Consistent Tapers
Garrison Tapers were worked out
mathematically according to Stress Curves
and show remarkable consistency
RodDNA shows that consistency
I can now demonstrate using RodDNA andstarting with the Garrison 215 Taper (8’ 6”,8wt 3 piece) that I can end up with a taper
extremely close to the Garrison 201 (7’ 5wt2piece)

Garrison 215 => 201

Garrison 215 => 201

Garrison 215 => 201

RodDNA Summary
Larry Tusoni has done a great job inproviding rodmakers a great new analyticalsoftware tool.
Too many features incorporated into
RodDNA then can be adequately
demonstrated or covered in this presentation
Available for download (Free) fromhttp://www.highsierrarods.com
I will be available latter to demonstrate theprogram for the small fee of a few cold beers.

Download Info for RodDNA

http://www.highsierrarods.com