What grain or line weight should I use for fast-sinking, intermediate and floating lines?

My 10-weight is about 10 years old, but I would like to use shooting heads on it. What grain or line weight should I use for fast-sinking, intermediate and floating lines? Knowing that a fly rod should be able to pick all the fly line from the water with one backcast, should I depend on a manufacturers line-weight guidelines? Can you recommend the correct grain or weight of line to use? -- via e-mail

Q My 10-weight is about 10 years old and has gotten a bit loopy, but I would like to use shooting heads on it. What is your opinion as to what grain or line weight I should use for fast-sinking, intermediate and floating lines? I have heard that a fly rod should be able to pick all the fly line from the water with one backcast, then shoot without benefit of false casting. Should I depend on a manufacturer's line-weight guidelines? Alternatively, can you offer a better recommendation for the correct grain or weight of line to use? I don't want to make a costly mistake, as fly lines and shooting heads are expensive.

Many anglers don't realize it, but if a fly rod is used hard for a long time, the glue that holds the graphite or glass together can sometimes break down, causing the rod action to soften. That is no reflection on the rod manufacturer. In some ways this might benefit a fly fisherman who intends to fish weighted fly lines. When throwing heavy flies or weighted lines, you don't want to throw loops that are too tight - it can cause serious leader tangles. A slower-action rod aids in making larger loops. So it is possible that your rod will function well with sinking fly lines, but you won't be able to throw those tight loops desired when casting floating lines.

The answer to the next question: The proper line weight for this now softer rod is fairly easy to ascertain. When casting floating lines, most of the time it pays to equip the rod with the manufacturer's recommendation. But, this does not apply to weighted fly lines. You can use several weighted lines on the same fly rod and cast well. Of course, if you over-weight the rod, you need to make your cast gentler. Also, too much casting velocity will cause shock waves in the line and leader. Despite your rod being softer, I would think you could easily cast any weighted fly line ranging from 300 to 400 grains. You may have a problem with floating and intermediate lines.

What is most important when fly casting heavy flies or weighted lines is that you never false cast them. False casting requires that at the end of the back or forward cast you must very abruptly change direction, and this causes all sorts of grief. Instead, rollcast the line out of the water in front of you. Allow it to straighten as it falls back to the surface. Then draw the line back until you can make a wide, open-loop backcast and let it go. If you didn't make a good open-loop backcast, drop it to the water and repeat the operation. Just don't false cast!

-Lefty