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Secret Fly Line

Secret Fly Line
Author Dave Whitlock’s striped bass catch rates on the Illinois River in Oklahoma at least doubled when he switched from opaque floating lines to clear intermediate lines.

Photos, and illustrations by: Dave & Emily Whitlock

The sight of a fly line in the air or on or below the water is often a disturbing sight to fish. Distract a fish that you want to grab your fly and it's an almost sure thing that it will forget eating even before your fly reaches the water. So, in certain situations, it makes sense to use a colorless fly line to reduce chances of disturbing your quarry.

Back in the late 1980s, Bruce Richards of Scientific Anglers introduced me to just such a stealthy fly line. SA had developed an almost clear, freshwater fly-fishing line that was intended for use in still and slow-flowing waters. They labeled it a Stillwater line. Some years before that, Shakespeare Tackle Company had made an almost colorless fly line for salt water they called a Slime Line which became popular with some bonefish and tarpon/permit guides.

I immediately liked what I saw (or didn't see) in the Stillwater WF5 Intermediate line from SA. It looked much like a 90-foot knotless leader. As you know, a leader is a low-visibility link between the fly and fly line. This Stillwater line was a low-visibility line between the fly and my backing. Bruce, who already knew that I enjoyed using intermediate lines, advised me that I could get excellent, stealthy control when making long, slow- to moderate-speed nymph, scud, and leech retrieves in very clear water at precise, shallow depths just over the tops of the aquatic vegetation and bottom structures.

My most outstanding success with clear intermediate lines for trout in stillwater occurred soon afterward on a lake on New Zealand's North Island. Dennis Black, founder of Umpqua Feather Merchants and longtime dear friend, took us to the lake to fish for rainbows and browns during a damselfly emergence. Using Water Master kick boats, we had minor success until we began using clear lines off the points over deep vegetationit was magical the difference this line made for catching bigger fish. Finally I hooked a true monster that was so fast and strong that I could do little but follow it across the lake. I saw it several times in the remarkably clear water. Finally it caught my leader on a sunken, dead tree branch and broke off. I estimated the rainbow to be around 20 pounds, the largest I'd ever hooked into.

Clear intermediate lines help lightly weighted flies ride under the surface but above rocks, weed beds, and other obstructions. Keep your rod tip close to the water during the retrieve and animate the fly by stripping line with your left hand so you don't cause the fly to ride up toward the surface. After the fly lands, use the count-down method to sink it to the required depth, and then begin your retrieve.

The news of our success spread rapidly in the area and I heard that a few months later another American using a clear intermediate line on that lake set the New Zealand rainbow trout recorda fish over 19 pounds. I'll bet it was the one that got away!

Now I always carry three spools when I'm fishing trout in stillwaters: a floater, a fast sinking-tip, and a clear, intermediate line. I've also been so pleased at how many other uses I've found in still, slow and fast-flowing waters for this remarkable fly line design, such as with wet flies, streamers, and diving flies. What's interesting is I've found that only a small percentage of fly fishers even own one and fewer use them regularly. Perhaps after you study what I have to say about clear, intermediate fly lines, you'll be encouraged to try.

(Arrow indicates wind or current direction) Opaque lines are highly visible and spook more fish. They are also affected by surface currents that can drag a belly into the line making it difficult to detect strikes. Intermediate lines get down below the surface and track in a straighter path, improving the action you can impart to your flies, and giving you better hook-sets.

Clear Advantages

These are fly lines that are constructed using a translucent nylon or fluorocarbon monofilament core with a coating of clear polyvinyl chloride (Scientific Anglers, RIO, Cortland) or polyurethane (Airflo). The coating surrounds the core and does not contain the air bubbles you'd find in the coating of a floating line or the tungsten powder used in sinking lines.

Intermediate lines have a sink rate of 1 to 1½ inches per second (ips) and most are made with a weight-forward taper. They are often identified on the product box by: WF-I.

The main purpose of intermediate lines is to make it more difficult for fish to see the line underwater. Before I began using clear lines I often spooked whole schools of landlocked stripers when my opaque, solid-colored lines passed over them. I easily tripled my striper hook-ups when I began using clear intermediate lines.

They create no wake near the fly to disturb fish because the fly line enters the water close to the fisherman, much like in conventional fishing. And because the line is not line floating on the surface, there is minimum drag from wind or surface currents. This is a fantastic solution to these very irritating drag problems.


Perhaps a more important advantage on windy days is that intermediate lines are narrower in diameter per line weight. In other words, an 8-weight intermediate line is narrower and less wind resistant than a 8-weight floating line. In windy conditions, a thin intermediate line is easier to cast long distances than a more bulky floating line.

In stillwaters a slow-sinking fly line allows for more precise subsurface, shallow- to moderate-depth fly control. You can fish in just a few inches of water over a weed bed, or in deeper water you can count down and allow the fly to sink deeper.

Where Do They Work Best?

Not only are these clear intermediate fly lines a perfect choice to use in stillwaters, I've found that they are just as superb in slow- and fast- flowing rivers. But you must expand your thinking each time before you choose a line for particular water conditions and always consider if the clear, intermediate line might work best.

Airflo Ridge Clear and Scientific Anglers Mastery Stillwater lines are both examples of completely clear, intermediate-sinking fly lines. RIO's Coldwater Striper line is an intermediate line with a clear head and a luminous running line for night fishing. The Camolux is at heart a clear, intermediate line but it has camouflage dyes mixed into the coating to make it even more stealthy in some situations.

Stillwaters. Intermediate lines are a great choice for precisely controlling the swimming of nymphs, scuds, midge larvae, and leeches. They are also a logical choice for long, swimming streamer retrieves or stripers chasing shad, or salmon after alewife or smelt. One of my favorite techniques when fishing with deer-hair waker flies, is to use a clear intermediate line to create a waking-diving-swimming-rising action, and at the same time avoid a line wake on the surface of calm, clear lake waters.

Rivers. Clear lines work well when drifting and swinging nymphs, wet flies, soft hackles, and streamers over fish in rivers, particularly when water flow is higher than normal. It's also excellent for long retrieves with streamer and diver presentations when casting from drift boats toward streambanks. And as mentioned previously, these lines are always good when it's windy.

Saltwater. A stealthy line is always a good choice on flats when casting to tarpon, bonefish, permit, and redfish.

In shallow water, a clear line may allow you to use a slightly shorter leader, which can improve your accuracy and success. For deep water tarpon fishing, remember that tarpon are always looking up. A clear line is likely to spook fewer fish while blind casting for tarpon in deeper holes.

A clear intermediate line should be one of your game plans during the course of the day whether you are fishing for trout, warmwater fish, or in the salt for larger species.

Hot and Cold Fishing

In the 1980s and early 1990s, I was doing a lot of winter striper fishing on Arkansas reservoirs, and the Stillwater line was my most productive fly line. Fast casts of 70 to 80 feet were necessary to get my threadfin shad flies presented to rolling, boiling pods of fast, spooky 10- to 40-pound stripers. The skittish stripers split when I pulled opaque lines over them, but they totally ignored the clear line.

Although it was formulated for cold water, I was fishing in frigid, below-freezing morning temperatures, and the line was nearly useless when I pulled the frozen line from the reel. To cope with these conditions I stretched the line indoors the night before, and kept it in a shooting basket until I hooked my first big fish.

Fly lines today are more carefully formulated to meet specific temperature ranges. Some are more supple for use in coldwater situations such as stillwater trout fishing, others are stiffer right out of the box for use in hot, tropical situations. Make sure you get the line designed for a specific temperature range. If you use the tropical line in cold water, it will likely be coiled and show too much memory. If you use a coldwater line in the tropics the surface of the line will become soft and difficult to cast, and the running line will frequently tangle.

I always attach the backing and the leader to the fly line with Zap-A-Gap knotless connections no matter what type of line I'm using. Most premium fly lines today come with welded loops front and back, but I find the loops to be bulky, and they hang up in the rod guides.

I recommend a short, knotless nylon or fluorocarbon leader and fluorocarbon tippet totaling about 6 to 8 feet. If using 2- or 3-fly soft-hackle or wet-fly combos, then 10 feet is ideal. The clear, shorter mono leaders enhance the effectiveness of intermediate line performance allowing the flies to hold at desired shallow to moderate depths (6 inches to 4 feet) as you typically drift, swing or slow retrieve the flies.

For spooky trout in clear tailwater fisheries, clear intermediate lines negate the effects of surface currents, and help you get just under the surface where many fish feed.

Boat Ramp Trout

I recently fished the White River in Arkansas, right above a public boat ramp. I only had about three hours to fish before dark, but when I arrived I found the river was about 2 feet higher, and much faster than I preferred.

I went there hoping to raise a few nice browns in low and slow conditions in the fading light of evening. I planned on using a rig of three wet flies on a floating line to simulate emerging caddis.

The high water was a bit frustrating, but that's a typical curve ball that tailwaters throw you. Searching for an option, I remembered I had a clear, intermediate line on an extra spool. That line, with the same three wet flies, allowed me to hook many 16- to 21-inch browns in three hoursmore than I had reason to believe possible that evening. The line/leader combination kept my flies precisely where the browns wanted to eat. I may also have been the only fly fisher on those 80 miles of White River using a clear intermediate line in swift water for trout. I guess you could say this fly line is a secret weapon of mine . . . at least until now.

Contributing editors Dave and Emily Whitlock live near Tahlequah, Oklahoma, where they operate the website

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