This documentation has not yet been updated for the new (April 2009) version of the program. Please see the What's New page for that information.

This Web page is based on Wayne Cattanach's Hexrod program, Rev 7-92, which was graciously supplied by Wayne. It uses Web "forms" to pass information between a set of cgi scripts written in Perl.

Wayne's Hexrod program was based on Everett Garrison's formulas, published in "The Book".

I was also inspired by Bruce Conner's Windows version of Hexrod.

You can find an archive of information about cane rods, the Hexrod program, and cane rod tapers at Jerry Foster's excellent Rodmakers Web Site. Jerry's site has a paper by Wayne describing the math behind the Hexrod program.

I'll try to keep a list of modifications and fixes here:

• December 17, 1996: First released.
• May 2002: Complete rewrite of the program, adding many new features.
• June 2002: Decided to change how the user can input ferrule sizes, making it easier for me an harder for the user :-(
• July 2002: Added the ability to set up private taper libraries.
• August 2007: Added option for DT or WF lines & more acccurate line weights

How to use Web Hexrod

The Web page has two initial input screens. The first is Basic Rod Design Parameters. On this screen, you enter the rod length, action length, line weight, number and size of ferrules, etc. At the bottom of the first screen you make a choice of the Rod Data Input, which takes you to the proper second screen. This is where you must enter either Rod Dimensions or Stresses, or start with a Straight Taper.

Once you have entered the dimensions or stresses, the program does some checks for data consistency and hopefully will find input problems and not just bomb or give stupid results. For instance, rod dimensions must be in a reasonable range of 0.0 to 1.0 inches, but if you enter a rod dimension of 184, it will assume you mean 0.184.

After the rod dimensions or stresses have been checked, the program calculates the other and displays the Basic Design Report showing the basic rod parameters and the dimensions and stresses at 5 inch intervals. At the end of this report you have several options for getting more detailed information or changing the analysis. These are your options:

Graphs

You can see the graph of the dimensions, stresses, or both combined on a single graph.

Tables

The Detailed Numbers table shows stress components at 1 inch intervals.

The Planing Form Settings table gives you the planing form station depths at intervals of your choosing.

Modify Rod Design

If you modify the Dimensions, you can specify new dimensions at every inch point.

If you modify the Stresses, you can specify new stresses at every inch point.

If you modify rod fundamentals, you can change rod length, ferrules, geometry etc. This is discussed in more detail below.

You can Edit the Stress Curve, and change the stresses on a graph. (This may not work well for you, if you have a slow internet connection.)

Save the Rod

This is described below.

Compare

Described below.

Assumptions and Quirks

In converting Wayne's program, I made a couple simplifying assumptions which I hope won't cause any grief. These were

• All lines are 90 feet long.
• Line weights come from the Cortland company website. See more info below. Line weights cannot be changed by the user.
• Ferrules are assumed to be evenly spaced.

These are some gotcha's:

• I extrapolated Wayne's line weights and ferrule weights for some larger and smaller sizes. Others contributed more ferrule sizes. The lines extrapolate easily (total line weight in grains = 3.2 times weight of first 30 ft), but ferrules are a guess. If you are fussy, then weigh your ferrules. Then choose the ferrule size that most closely matches the weight (see below.)
• If you go back and forth, calculating stresses from dimensions then recalculating dimensions from stresses, the dimension values in the first few inches of the rod tip get tiny. (This seems to happen in Wayne's program also.) I did not try to determine what is going on there. (Recall that Garrison did not use the dimensions near the tip from his math either; he considered these computed dimensions impractically small.)
• Because of the way information is passed between program screens, a browser "Reload" will sometimes bring back a screen without data. Use the "Back" button to go back to a good screen, reload it, and go forward again. This can affect how you correct entry errors; you may have to return and fill in the entire screen again.
• Finally, I try to avoid working on the program when someone seems to be using it (I check the server logs), but when I do work on it there is the possibility that I will break something. Or change my mind about how something should work and change your answers from the last time. The program is always "live", and there are now so many parts that it is hard to make a separate copy to work on. "You get what you pay for."

Definitions of Terms and Descriptions of Special Features

Private Taper Library

Normally, when you save a rod, it gets put in a temporary directory where things get removed after 3 days. A private taper library lets you save things for as long as you want. Choose a library name (probably something based on your name) and enter it. You will be asked for your name and email address. After that things should be pretty self-explanatory.

We are all on the honor system here, so please don't try to guess other people's library names and snoop at their tapers. OK?

Rod and Action Length

In case there is any confusion, the Rod Length refers to the entire assembled rod, from tip to butt. The Action Length is the length from the tip to as far as you want to analyze dimensions and stresses.

The action length may end at the front of the grip, or may extend into the grip and reel seat. It should never be longer than the rod length.

If you have a two-piece rod with unequal sections, you can analyze it by cheating a little. Specify the action length as usual, but specify the rod length as twice the tip length, whatever that is. That will place the ferrule where it should be for the stress calculations.

Line Weight & Taper

As of August 31, 2007, separate line weights are used for DT and WF lines. These were compiled/computed from the Cortland website by Chris Carlin. They specify the weight of each foot of line for each taper and line weight from 2 through 12.

Previously, a more generic line weight was used, just by extrapolating the weight of the first 30 feet (the AFTMA standard) over the entire length of the line. The new more detailed line weight data provided by Chris makes possible a more accurate estimate of both the weight of line being cast and the weight of the line in the guides, one of the components of stress. So users will see a change in stress values with this switch to more detailed line weight info.

Specifying Ferrule Weights

From the point of view of stress calculations, the only thing about a ferrule that matters is its weight (and its location, of course).

Ferrule weights are supplied for sizes 8 thru 32 -64th in standard and truncated lengths. They correspond most closely to nickel silver Super Swiss style ferrules of the type produced by CSE. Some of the weights come from Wayne's original program, from measurements others have sent me, and from my own limited measurements. Some in-between sizes I've estimated as best I could. (Yes, someone requested ferrules as large as 32/64!)

If you are using a ferrule that is unusual in material, type or size. and you know its weight in ounces, use the table below to choose the size and type (standard or truncated) that most closely matches the weight, and then use that ferrule "as if" it were the correct one. Tell the program not to adjust the ferrule size.

Tip Impact Factor

Garrison incorporated this parameter (set to 4.0) in his stress equations, without a clear explanation. My understanding is that, this number multiplies all the moments (line, bamboo, guide, varnish) to account for the stress created by pulling the line through the air during the cast. Increasing it will increase the stress values calculated. Change it if you dare :-)

The Tip Factor is the weight of the line beyond the tip (and the weight of the tip guide, fwiw).

Cane Density

Garrison calculated the denisty of Tonkin cane as 0.668 ounces per cubic inch. This parameter may be adjusted if you are building with another material.

Saving and Retrieving a Rod Design

Another option is to save the rod design. This writes a copy of the rod parameters, dimensions and stresses to a disk file with a short name (8 or fewer characters) that you choose. This file is written to a temporary directory, where files are deleted after 3 days.

Be sure to choose a unique name; if you call your rod "test" and so does the next guy, he will clobber your file. Note that the name you enter is case sensitive, so "Payne101" is distinct from "PAYNE101" and from "payne101". I won't be responsible for lost or clobbered files, so make a printed copy if the rod design is important to you!

Modifying Basic Rod Parameters

One of the principal uses of the concept of rod stress is to assist in designing a new rod from an existing rod. With this program, you can modify one or more of these basic rod parameters:

• Rod Geometry (Hex, Penta, or Quad)
• Line weight
• Length of line cast
• Number of ferrules
• Type of ferrules
• Length of rod action
• Tip Impact Factor
• Cane Density

Then, you can rerun the program, holding constant either the stresses or the dimensions.

This is the logic:

• If you want to try a different line weight, or length of line cast, then you perhaps want to hold the dimensions constant and see how the stress values look under this change.
• Or, perhaps you want to find the dimensions of a rod that will cast a different line with the same stress curve. In this case, hold the stress curve constant.
• If you want to change the number or type of ferrules, then you may want to hold the dimensions constant and see how the stress values change.
• Or, perhaps you want to replicate the same stress curve in a rod with a different number or type of ferrules. So hold the stress curve constant and recompute dimensions.
• If you want to change the rod length, then perhaps you want to replicate the rod's stress curve, but in a longer or shorter rod. In this case, hold constant the stress curve.
• Or, perhaps you want to make a short rod from the two tip pieces of a three-piece rod. In this case, hold constant the dimensions. (Also, change the number of pieces from 3 to 2!)

When you change the action length, this is what happens:

• If you change the rod length and hold the stress curve constant, the previous stress curve is uniformly stretched or shrunk to the new rod action length.
• If you change the rod length and hold the rod dimensions constant, the butt end of the action is shortened by truncating (like when you slam the car trunk on the rod butt) or by extrapolating the rod taper near the butt.

(If you want to shorten the rod at the tip, like when the screen door closes too fast, this program cannot help. I'm sorry on both accounts.)

The critical thinker now asks, "If I am recomputing the rod dimensions, say for a longer or heavier rod, how do I know what size the ferrules will be?"

Good question. If you hold constant the stress curve and recompute dimensions, the program will iterate until it finds the correct ferrule sizes for you. That is why the ferrule size boxes are blank. But if you put in values, the program will use those ferrule sizes.

Comparing Two Rod Designs

Sometimes it is useful to compare the stress curves or dimensions of two rod designs, say before and after a modification. Enter the first design and "Save" it, with a unique rod ID or name. Then develop the new rod design and enter the rod ID of the saved rod in the "Compare" box. The comparison shows the two rods side by side in tables and graphs.

It helps if the two rods have different descriptive names, since these are used on the output.

Finally

If you find any bugs, have suggestions for improvements, etc. let me know at fcstetzer@gmail.com.

Just for the record, I promise not to peek at anyone's rod designs :)

Back to the Hexrod Program

"I'm not a programmer, but I play one at work."
--
Frank Stetzer
Milwaukee, Wisconsin, USA