As I review this segment again, either some new stuff has been added or I missed alot when I first read it. As I try to understand the WL to IP formula, 3.33 is the multipiler used to figure fly line load. In my case, 3.33 (135) - 10 = 440 grains. In figure 3 I can plot my point and it looks like 440 would equal (30' I assume) a bit under 13.5 weight line. So I'm a bit confused in a previous post where my original thinking of 135 pennies that gave an ERN of 13.41 that a 13.4wt line would load the rod properly - but the formula indicates 30' of 13.4 wt fly line would load based on the WL to IP formula - I'm missing something here, seems like I went in a circle and wound up with the same answer.

But my biggest question is further in the segment where 4.44 is used as the multiplier for sinking line. So the first 30' of 10wt sinking line is a 1/3 heavier than the first 30' of weight forward floating line? Thanks.

If you use the inventors original suggestion (and that's all it is - a suggestion) that ERN=ELN, you have to remember that this is with 30 feet of line beyond the tiptop. As you move more line beyond the tiptop, the load on the rod increases.

Per your original question, most 10-weight rods are intended to cast and fish as fairly long ranges, say 60 to 100 feet. This is why most commercially produced 10-weght rods will have power figures (ERN) of well over 10 to 10.5. A rod with an ERN of 13 may indeed load nicely with 70 feet of 10-weight line beyond the tiptop.

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