F-Flies: 4 great patterns for grayling and trout fishing

Synopsis

Learn how to tie and fish four simple F-flies for grayling and trout. Includes material lists, step-by-step tying photos, a dry fly leader setup and tips for keeping CDC flies afloat.

Introduction

F-flies are among the most versatile dry flies you can carry. Tied with a simple CDC (Cul de Canard) feathers, they imitate emerging upwinged flies, caddis and midges sitting in the surface film, which is exactly where trout and grayling feed when they’re being fussy

Devised by Marjan Fratnik in the early 1970s, the F-fly has earned a place in my box for rivers like the Welsh Dee as well as small stillwaters and reservoirs. They’re also one of the easiest dry flies to tie, so they suit beginners.

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

In this guide I’ll show you how to tie four of my favourite patterns (olive, purple, peacock quill and peacock herl), when to fish each one, the tackle and leader setup I use, and how to keep a CDC wing floating through a busy day.

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, so 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.

Tying material list:

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

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, so 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.

Step 1. Catch the waxed tying thread onto the hook 1 mm behind the eye. Wind the thread in touching turns down the shank to the hook bend.

Step 2. Tie in a length of fine gold wire, followed by a strand of peacock herl, at the hook bend. Trim the waste ends.

Step 3. Wind the thread forward to 3 mm behind the eye. Then wind the peacock herl in touching turns towards the hook eye, tie it in and trim away the waste.

Step 4. Counter-wound the gold wire against the herl in evenly spaced turns to reinforce the fragile body. Tie it in and trim the waste.

Step 5. 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. Make another 3 or 4 wraps of thread and trim the waste ends of the CDC feathers.

Step 6. Build a small head with olive thread, whip finish, and coat with varnish to finish the fly.

Tip: for a red-tag variant, tie a short tag of red thread or floss in at the bend before the wire and herl.

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.

Key Takeaways – F-Flies

• Versatile: F-flies imitate emergers, caddis and midges in the surface film, so one pattern covers many hatches.
• Beginner-friendly: the olive F-fly uses only two materials (thread and CDC), which makes it a good first fly to tie.
• Match the pattern to the conditions: olive is my early-season all-rounder, purple suits summer Iron blue dun hatches, peacock quill works when fish are fussy, and peacock herl (sometimes with a red tag) is my autumn grayling fly on the Welsh Dee.
• Sizes: tie them on #14 to #18 hooks, and carry a range of sizes and thread colours.
• Leader setup: use a 9ft 5X leader with a 3 to 4ft fluorocarbon tippet, with the tippet degreased using Fuller’s earth and the rest of the leader greased to float.
• Float maintenance: CDC floats because its fibres trap air and are waterproofed with natural oils, but it needs cleaning and drying after each fish.
• Restoring a waterlogged fly: rinse off fish slime, squeeze the wing dry in a microfibre cloth, apply a little CDC oil floatant, then false cast.

Conclusion

F-flies prove that the best dry flies are often the simplest. With a few CDC feathers, some thread and the occasional peacock herl body, you can cover emerging olives, Iron blue duns, caddis and midges on rivers and stillwaters.

If you’re new to fly tying, start with the olive F-fly, then add the purple, quill and herl variants as your confidence grows. Fish them in the surface film on a fine, degreased tippet, and keep the wing dry between fish, and you’ll have a pattern that often catches when other dry flies fail.

Have you got a favourite F-fly variation, or a different way of keeping CDC afloat? Leave a comment below. If you’d like to try these flies on the Welsh Dee, see my guide to fishing the river.