Re Rod design AGAIN - tsmithwick

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On Jun 16, 2008, at 2:26 PM, R&A Norwood wrote:

> In fact any new rod design should start with the required  
> specifications for that rod

Hi Bob - I think you are right that the designer should have specific  
characteristics in mind. Here is a scenario for you to consider. This  
has been a back burner project that evolved in fits and starts over a  
few years, and I'm not telling the full story here for the sake of  
brevity. Basically, I was asked to produce a rod to the following specs:

It is designed for bank fishing on larger spring creeks, and should  
cast a 3 weight line.

It should be of a length and speed that would hold the line high in  
the air on false casts, and easily keep the line out of the weeds.

The weight should be be appropriate for a 3 weight, so that the rod  
did not feel like a 5-6 weight casting a 3. It should load easily in  
close.

The rod should false cast 50 feet of line. ( The guy who wants the  
rod is a great caster )

To keep the weight reasonable, I decided to go with 8 footer, and  
hollow build. Not knowing of any such taper, I started out by putting  
a 3 weight line on an F.E. Thomas 4 weight 8 footer. It would cast  
the line a good distance, but it was obviously not loading properly,  
and felt too heavy for the line. Here's the Thomas taper, just for  
reference:

0- .062
5- .075
10-.103
15-.118
20-.130
25-.142
30-.153
35-.165
40-.183
45-.192
50-.204
55-.216
60-.228
65-.234
70-.258
75-.274
80-.285
85-.304
87-.314

For the first attempt, I decided to try a step down taper, figuring  
about .010 across the ferrules. I kept the Thomas butt, hollow  
building it, but designed a Garrison style tip to be built solid,  
slightly on the beefy side to handle the length of line. Here's the  
new tip.

.062
.072
.093
.109
.122
.136
.148
.160
.172
.184
.196

It took a while, but I finally got the rod built late last year. It  
felt pretty good, and fished well, but I didn't think I had the 50  
foot false cast, although the rod did cast further than most 3  
weights without much effort, and did feel good in close. I thought  
maybe the step down was keeping the butt out of the action. Last  
weekend, I attended the Heritage Day the PA Museum of Fly Fishing,  
and met up with the guy who inspired the rod and watched him and a  
some other good casters cast the rod. All got about the same result,  
the rod cast very smoothly with 40-45 feet in the air, then just ran  
out of gas. Some other makers were watching, too. It became apparent  
that it was not the step down, the rod flexed through the ferrule but  
stopped loading half way down the butt. The butt swells significantly  
in that area, and the 3 weight line and tip just could not bend it,  
so the lower butt contributed nothing to the cast. Close, but no cigar.
Starting at 50", here's what I would do the next time, feeling that  
the basic idea worked, I'm just going to significantly lighten up the  
lower butt, keeping the swell, but reducing it significantly.
.204
.216
.228
.238
.250
.27
.29
.31
.33
.340

Having fallen under the influence of Mr Harms, and his cabal of  
convex taper theorists, I would also slightly rework the tip to:
.062
.080
.095

All of this worked out with graph paper, not stress curves, although  
the tip stresses should certainly look familiar.