When to Use an Intermediate Sink Fly Line

An intermediate sink fly line excels in many situations.

The intermediate sinking line is my go-to for well over half of the fishing I do. Sight fishing tarpon in spring. Throwing at bridge lights for snook. Surf fishing for snook and tarpon. Blind casting for mackerel and seatrout. What these fisheries have in common is the need to get the fly well under the surface. In some cases, it's about getting your line under the surface, too, wherever floating seagrass can foul your fly, or surf swells can ruin your presentation.

Intermediate lines sink on average at about one inch a second. Some come in at 1.25. They come with either clear or opaque coatings, though a few, such as the Scientific Anglers Sonar saltwater intermediate I am fishing lately, have a clear front section and sky blue running (shooting) line. I love the clear intermediates for the stealth factor primarily. For years I've relied on the all-clear Scientific Anglers Tarpon Taper line; I like the pebbly texture of its shooting section. It buzzes through the guides and it seems long casts are easier.



Like most modern intermediates, the Sonar line casts like a floating line rather than a heavier sinking line.This is due to a gradual taper change from head to running line, unlike the abrupt taper that was a drawback of “old school” sinking lines. No more “hinging” or a need to chuck and duck! The intermediates, unlike heavier sinking lines, don't come to a stop as abruptly, either. There is a smoother transition between your backcast and forward stroke.

If you really need a fly to “bomb” to the bottom in a hurry, or you are in over 6 to 8 feet of water, by all means rig up a faster rate sinking line. Otherwise, you can fish a heavier fly and a short leader to increase the sink rate of your fly. Leaders of 4 to 6 feet are plenty long with the clear or clear-tip intermediate lines. I have been on hot bites with pomps, macks, blues and snook in the surf, and made fly changes until my leader was barely two feet long. It did not deter the fish. Consider the clear fly line to be an extended butt section.



For night snook, I tie a perfection loop on a 4-foot piece of 25- to 40-pound fluorocarbon and loop it to a whipped or welded loop of my flyline. When fishing midday in the clear summer surf, I go a bit longer, 6 to 7 feet, and taper my leader from 40- to 25-pound, or 50 to 30 for better turnover.

THE CAST

Because an intermediate sinks slowly, you can't pick it off the water for a second cast as you would a floating line. You'll need to strip it in until perhaps 15 feet of it is outside your rodtip. I normally fish my fly to the boat and then roll that length, and my fly, out of the water, make one back cast and then shoot another cast. This does not give you an immediate second presentation to a fish when your first shot is off-target. However, with species such as flats permit, pompano or surfacing bonito offshore, a second shot is rare anyway. Those fish move quickly. And a tripletail on a marker or float isn't going anywhere. If you miss the first shot, strip in and cast again. Truth be known, even a string of tarpon coming to the bow can be swimming at a pace that forces you be on the mark the first time. I'd rather have the intermediate line's sinking rate that gets the fly into the strike zone than have a second shot. FS

Published Florida Sportsman May 2019