F Flies: 4 great patterns for grayling and trout fishing

F flies are easy to tie and probably the most versatile dry fly patterns because they can imitate many insects inhabiting rivers and stillwaters. For example, emerging up-winged flies, caddisflies, and midges.

Also, if you’re new to fly tying, the simplicity of these dry flies makes them a great place to start your fly tying journey.

Since their creation in the early 1970s by Marjan Fratnik, F fly patterns based on a natural CDC feather wing have become popular and found in most dry fly boxes.

I never go grayling or trout fishing without several CDC dry fly patterns in my fly box, tied in different sizes and colours.

So, let’s take a look at…

How to tie the F flies I regularly fish:

First up is the olive F Fly. This CDC dry fly is my early-season go-to pattern that will work almost anywhere, whether you’re fishing rivers, streams, small stillwaters, or big reservoirs.

If you are new to fly tying, this is the pattern I would recommend you start with because it’s the simplest (only two materials) and will catch trout and grayling.

Tying material list:

• Hook: #14 to #18 HENDS BL354
• Thread: 8/0 Olive Uni Thread
• Wing: 2 CDC feathers

Step 1. Catch the waxed tying thread onto the hook 1 mm behind the eye. Wind the waxed thread, in touching turns, towards the hook bend and back up the shank, stopping 3 mm behind the eye.

Step 2. Take 2 CDC feathers and place them side by side, making sure that the tips of the feathers are level. Catch them in position with two wraps of thread. Adjust the length of the feathers so that they slightly protrude past the hook bend. Now make another 3 or 4 wraps of waxed thread and trim the waste ends of the CDC feather.

Step 3. Build a small head with olive thread, whip finish, and coat with varnish to finish the fly.

This purple body variant is tied using purple instead of olive thread.

I also tie these simple F flies using a range of coloured threads, e.g. black, purple, red, brown, yellow, and grey. This collection allows you to cover a multitude of emerging insects.

For example, a purple variant is often a winner during the summer when Iron blue duns are hatching,

Peacock Quill CDC F Fly

In addition to the thread-bodied CDC flies, I find a variation tied with a stripped peacock herl body an effective fly when the fish are fussy.

• Hook: #14 to #18 HENDS BL354
• Thread: 8/0 Olive Uni Thread
• Body: Stripped peacock quill
• Wing: 3 CDC feathers

Tying material list:

Step 1. Catch the thread onto the hook and wind down the shank in touching turns towards the hook bend. Next, take a stripped peacock quill and tie it in using the waxed thread.

Step 2. Wind the waxed thread in touching turns up the shank toward the eye. Grip the peacock quill with a pair of hackle pliers and wind it up the hook shank in evenly spaced open turns. Tie in the quill with the thread, trim away the waste, apply a thin coat of varnish over the body and allow it to dry.

Step 3. Take 2 CDC feathers and place them side by side, making sure that the tips of the feathers are level. Catch them in position with two wraps of thread. Adjust the length of the feathers so that they slightly protrude past the hook bend. Now make another 3 or 4 wraps of waxed thread and trim the waste ends. Finally, build a small head with olive thread, whip finish, and coat with varnish to finish the fly.

The final pattern I carry in my fly box is an F fly tied with a peacock herl body, a deadly dry fly pattern for grayling fishing in autumn on the Welsh Dee.

Peacock herl F fly

• Hook: #14 to 18 HENDS BL354
• Thread: 8/0 Olive
• Body: Peacock Herl
• Rib: Fine gold wire
• Wing: 2 CDC feathers

Sometimes, the addition of a short red tag to this CDC fly pattern improves its effectiveness.

How to fish F Flies.

On rivers and stillwaters, this class of CDC dry fly performs when trout and grayling are feeding on flies sitting in the surface film.

Equipment-wise, I use a 9ft 5# rod for dry fly fishing. Attached to the floating line is a 9ft 5X copolymer leader tipped with a 3 to 4 ft length of 3lb fluorocarbon. Fuller’s mud is applied to the fluorocarbon tippet to remove its shine and make it sink, while Mucilin grease is applied to the remainder of the leader so that it floats.

The only drawback of these dry flies is the CDC wing needs cleaning and drying after catching each fish to keep them afloat. However, it’s a price worth paying because of its effectiveness.

Keeping CDC Flies afloat:

It’s important to understand that it is the structure of the CDC feather that keeps them afloat.

Each fibre of a CDC feather contains thousands of tiny hairs that trap air, which is the primary floatation mechanism. In addition, oil from the duck’s preen gland waterproofs the feathers.

When necessary, I treat the CDC wing with a CDC oil-based floatant that restores the feather’s natural oils without clogging the tiny barbs (e.g. Veniards CDC Oil, TroutHunter CDC Fly dressing).

When the fly fails to float, I restore it by:

• Rinsing any fish slim off with water.
• Dry the wing thoroughly by squeezing it between a dry household microfibre cleaning cloth.
• Apply a tiny amount of CDC oil-based floatant between your thumb & forefinger and rub it onto the wing.
• Make a few false casts, and it’s ready to…

catch a few more trout and grayling.

Finally, I hope this dive into CDC fly tying stimulates you to tie some F flies and test them at local fishing venues or take a trip to fish the Welsh Dee, where they catch fish when other dry flies fail.