Mathematics and Fly Fishing

The Loads on the Rod

In order to compare two stress curves, it is essential that the loads are the same for both curves.

The loads Garrison used presents a possible load condition.

The loads Garrison used may be regarded as standard loads for rod design. It is tempting to change the loads, as it is done in some of the programs based on a Garrison stress curve, but if we do, we would have to start all over and find out how the stress profiles for Garrison's rods are, when we use other loads.
Using a Garrison stress curve for other loads, than those originally used to calculate the curve is like reading in tealeaves.

Regardless of what kind of cast we are making, there is only a short period of time when the line is perpendicular to the rod at the point near the handle, where we start our calculations.

It is important to understand, that no calculatings to this date - that includes my own programs - are exact. We do not have the necessary information or the mathematical tools. Rodmakers have been overinterpretating the information given in Garrison's book. Carmichael has clearly stated that he has all his technical information from Garrison, and when he finished the book by himself, he could not check the technical details with Garrison. So there are some errors.

The loads and how to calculate them are discussed in Garrison and Carmichael's book.

The program UniRod can be modified to calculate the deflection and stresses for any angle between the line and the rod, but we have to choose one angle (90 degrees) for the calculations of a new rod.
The rod is not fully loaded at that point, but the stress profile does not change too when increasing the load.

Download of programs.