07-04-2009, 12:42 AM
Re: sink rate formula????
A couple of things to think about in your post.
The first is loading the rod for a cast.
The second has to do with current speed of the river you plan to fish, but that's a whole 'nother post- suffice it to say that in moving water, while the line is sinking, the line is also being swept downstream. The deeper the depth you want to reach and the faster the current, the further upstream you'd have to cast to get to the depth of your target. The effect of current speed in moving water would argue for faster sinking set ups.
There are a couple of ways to use T8, T14 etc. One way is to whack them up into different lengths 5' 10' etc and put them ahead of a regular fly line- a floater for example. If you carry different lengths with loop to loop connections you can change on stream easily. These are similar to poly leaders that you can buy in different lengths and densities. If you do this you'll be relying on both the weight of the 5 or 10' section of t8 (or whatever) as well as the weight of your fly line that's outside the tip to load the rod.
The other way is to build a shooting head out of the T8 (or Twhatever). To do this you want the length of the Twhatever to be enough weight to load the rod and carry the shooting head out of the guides.
This will get confusing, but stick with me here. The aftma guidelines for the weight in grains for different line weights are based on the first 30 feet of fly line within a "tolerance" of low and high range. So 3 flylines of 120, 115 and 126 grains would all be considered "4 weight" fly lines. Since the line rating is based on 30 feet, I added a column to show what the grain weight of these same lines would be if you had 40 feet outside the tip to load the rod. Basically every 10 feet of additional line outside the tip beyond 30' is the equivalent of going up 1 line weight. The reason I mention this is that shooting heads typically have grain weights equivalent to 2 line weights heavier than the standard line rating of the rod to load it, which would be the equivalent of working with more than 30 feet outside the tip with a regular line. Here's the chart:
1 60 54 66 80
2 80 74 86 107
3 100 94 106 133
4 120 114 126 160
5 140 134 146 187
6 160 152 168 213
7 185 177 193 247
8 210 202 218 280
9 240 230 250 320
10 280 270 290 373
11 330 318 342 440
12 380 368 392 507
So for a 9 weight, which would have a 240 grain AFTMA rating for the first 30 feet, you'd actually be loading up the rod with 320 grains if you usually carry 40 feet in the air. If you want to use the same head on both your 9 and 10 weights, you might want to start with 350 grains.
So if you want to make a shooting head, and keep it under 30 feet, T14 weighs 14 grains per foot, so if you mark off a section of 25' (350 grains) you could start there to see how it feels. Just mark it and try a few different lengths outside the tip before you cut. (To get 350 grains in a T8 it would take a bit under 45 feet.)
Hope this helps....