Rod Mathmatics Note

Discussion in 'Tackle and Rigging' started by pametfisher, May 19, 2009.

  1. pametfisher

    pametfisher Senior Member

    1,386
    30
    I saw these two interesting posts today and wanted to make a suggestion to anyone who loads their rod at home to determine the maximum drag that a rod can withstand. There are two ways that people are doing the test (and sometimes for fun):

    (Disclaimer, I'm not a rod builder and there is a lot about the interaction of guides and rods that I know little about. I'm just going to estimate the forces.)

    1. Load applied using a reel and tensioned line: Line from Reel Through Guides

    2. Load tied to tip guide: Line from Tip

    These methods are not equal. A line tied to the tip (although it might be too much for the tip guide to hold) is a lower total load on the rod. Since the number of guides on the rod matters too, I've done the simple, tip guide only analysis.

    If you tie a 20# load to the tip of the rod, the load on the rod is 20 pounds.

    If you run a line from a reel, through the tip guide to that same 20 pound weight and assuming that you're holding the rod so that the tip is level with the butt as in each photo, the load on the rod is about 28 pounds, about 40% higher.

    Staying with the line strung from reel example for a moment, if you add several guides and run the line through them but lift the tip to the height of the butt, the load on the rod gets to about 35 pounds. But the load is also shifted somewhat to the stronger part of the rod.

    The simple explanation for why the example with the reel is a heavier load is that the line has 20 pounds on each end--the 20 lb. weight on one end, and the 20 lb. countering force at the reel on the other.

    So if you're trying to get an idea of how much your rod can handle, I would suggest stringing it with line through all the guides and attached to a reel, and be very careful about lifting the rod above horizontal or the tip to the height of the butt.
     
  2. MrBill

    MrBill Senior Member

    2,835
    107
    So if you're trying to get an idea of how much your rod can handle, I would suggest stringing it with line through all the guides and attached to a reel, and be very careful about lifting the rod above horizontal or the tip to the height of the butt.

    I've said this same thing at least five times over the years on this board. I'm glad that a practical man and a mathematician agree on something.:)
     
  3. YMMV

    YMMV Senior Member

    178
    1
    Good stuff as always pametfisher!