Overcast Olive CDC Comparadun
by @dekasso
CDC Comparadun · Dry fly
A white sail on a grey afternoon
A hackleless CDC Comparadun in olive and white, size 18, for trout sipping blue-winged olive duns on slow water.
An olive CDC Comparadun rests on a grey slate ledge, its white wing standing tall over a slim tapered body. Split dun tails, an olive thread body and a single white CDC tuft are the whole fly.
- Pattern
- CDC Comparadun
- Imitates
- Blue-winged olive hatch
- When
- typically grey spring and autumn afternoons
- Hook
- size 18
- Tippet
- 6Xrule of three
- White CDC wing, no hackle
- Slim tapered olive thread body
- Split dun microfibbet tails
- Size 18 dry fly hook
- Matches blue-winged olive duns
On the water
A pale fan of white CDC stands up from a thin olive body. Fine dun tails split wide behind the bend. No hackle, nothing extra. It sits on dark slate like a dun drying its wings.
Fish it when the sky goes flat and small olives start riding the glides. Cast above the rise, mend once, and let it drift drag-free. The body rides low in the film while the white wing stays easy to follow.
Split microfibbet tails do the balancing on a fly with no hackle. Get them spread evenly on either side of a tiny thread bump and the fly lands upright, cast after cast.
Rigging
- Tippet
- 6Xhook size divided by three
- Leader
- Nine feet, tapered — longer and finer in flat water
- Pair it with 6X or 7X tippet and a long leader for flat, clear water.
- Dead drift it; a reach cast or a single upstream mend keeps drag off the fly.
- Dry the CDC with a few false casts and a dab of tissue after each fish.
Where and when
- Hatch
- Blue-winged olive hatchtypically grey spring and autumn afternoons
- Target
- Trout
- Water type
- Slow glides, flat pools and spring creeks
- Also fishes
- Also fishes well in light rain and drizzle, on still pools and in the soft edges of riffles where duns gather.
Make it yourself
Intermediate4 materials · 10 steps
- Pattern
- CDC Comparadun
- Style
- Dry fly
- Hook
- Dry fly hooksize 18
- Thread
- Olive 8/0
Materials in the order they go on the hook
- WingWhite CDC
- TailDun microfibbets
- BodyOlive 8/0 thread
- HeadOlive 8/0 thread
Details
- Imitates
- Mayfly dun (blue-winged olive)
- Colors
- Olive, White, Pale dun
How to tie it
The steps, from first wrap to whip finish (10)
- Mount the hook and lay a thin olive thread base from the eye back to above the barb.
- Stack two or three white CDC feathers with tips aligned and tie them in a third of the shank back from the eye, tips forward.
- Set the wing length to about one hook shank, then trim the butts at a taper and cover them with thread.
- Build a small thread bump at the bend to act as a splitter for the tails.
- Tie in two or three dun microfibbets on each side, splaying them around the bump, about one shank long.
- Wrap a smooth olive thread body forward, slim at the tail and building toward the wing.
- Lift the wing upright and build a small thread dam tight in front of it.
- Make a few figure-eight wraps around the wing base to shape a short thorax.
- Form a neat olive thread head behind the eye.
- Whip finish and trim the thread.
Proportions (4)
- Wing: roughly one hook shank tall, standing upright.
- Tails: about one shank long, split evenly to each side.
- Body: slim taper from bend to wing, no thicker than the hook eye at its widest.
- Head: small and tidy, a few thread wraps behind the eye.
Tips (3)
- Keep the thread flat by spinning the bobbin counterclockwise for a smooth, segmented body.
- Use fewer CDC feathers than you think; a sparse wing floats and casts better.
- Press the tails into place with your thumbnail before locking them down to get an even split.
Common mistakes (3)
- Wing set too far back crowds the body; tie it in a third back from the eye.
- Tails bunched together let the fly tip over; build the thread bump first so they split cleanly.
- A lumpy thread body spoils the slim look; wrap in even, overlapping turns and avoid backtracking.
Every kit size
Materials only
Size 18 · Materials only · 12 flies
$25.85
$2.15 a fly
Includes Dry fly hook · and 5 more
Every item in this kit · 6 items
Hooks & beads
- Dry fly hook$6.50
Thread & wire
- Olive 8/0 thread$2.95
Materials
- White CDC$6.95
- Dun microfibbets$3.50
Finishing
- Head cement$5.95
Guide
- Printed recipe and tying stepsIncluded
Size 18 · Materials only · 48 flies
$49.54
$1.03 a fly
Bought separately $52.15 · you save $2.61
Includes Dry fly hook · and 5 more
Every item in this kit · 6 items
Hooks & beads
- Dry fly hook$13
Thread & wire
- Olive 8/0 thread$8.85
Materials
- White CDC$20.85
- Dun microfibbets$3.50
Finishing
- Head cement$5.95
Guide
- Printed recipe and tying stepsIncluded
Size 18 · Materials only · 144 flies
$117.57
$0.82 a fly
Bought separately $133.60 · you save $16.03
Includes Dry fly hook · and 5 more
Every item in this kit · 6 items
Hooks & beads
- Dry fly hook$35
Thread & wire
- Olive 8/0 thread$26.55
Materials
- White CDC$55.60
- Dun microfibbets$10.50
Finishing
- Head cement$5.95
Guide
- Printed recipe and tying stepsIncluded
With vise & tools
Size 18 · With vise & tools · 12 flies
$175.85
$14.65 a fly
Includes Dry fly hook · and 14 more
Every item in this kit · 15 items
Hooks & beads
- Dry fly hook$6.50
Thread & wire
- Olive 8/0 thread$2.95
Materials
- White CDC$6.95
- Dun microfibbets$3.50
Finishing
- Head cement$5.95
Tools
- Rotary pedestal vise$79
- Ceramic bobbin$14
- Fine-point scissors$16
- Whip finisher$9
- Hackle pliers$7
- Bodkin$5
- Bobbin threader$4
- Dubbing wax$4
- Canvas tool roll$12
Guide
- Printed recipe and tying stepsIncluded
Size 18 · With vise & tools · 48 flies
$192.04
$4 a fly
Bought separately $202.15 · you save $10.11
Includes Dry fly hook · and 14 more
Every item in this kit · 15 items
Hooks & beads
- Dry fly hook$13
Thread & wire
- Olive 8/0 thread$8.85
Materials
- White CDC$20.85
- Dun microfibbets$3.50
Finishing
- Head cement$5.95
Tools
- Rotary pedestal vise$79
- Ceramic bobbin$14
- Fine-point scissors$16
- Whip finisher$9
- Hackle pliers$7
- Bodkin$5
- Bobbin threader$4
- Dubbing wax$4
- Canvas tool roll$12
Guide
- Printed recipe and tying stepsIncluded
Size 18 · With vise & tools · 144 flies
$249.57
$1.73 a fly
Bought separately $283.60 · you save $34.03
Includes Dry fly hook · and 14 more
Every item in this kit · 15 items
Hooks & beads
- Dry fly hook$35
Thread & wire
- Olive 8/0 thread$26.55
Materials
- White CDC$55.60
- Dun microfibbets$10.50
Finishing
- Head cement$5.95
Tools
- Rotary pedestal vise$79
- Ceramic bobbin$14
- Fine-point scissors$16
- Whip finisher$9
- Hackle pliers$7
- Bodkin$5
- Bobbin threader$4
- Dubbing wax$4
- Canvas tool roll$12
Guide
- Printed recipe and tying stepsIncluded
The creator
How it was made
2 iterations led here; the saved one is marked
1
2 Saved
Remixes
4 steps back
- Slate Ledge Grizzly Soft Hackle@dekasso · the original
- Grizzly Half Hackle Mayfly Dun@dekasso
- Evening Ember Sulphur Mayfly Dun@dekasso
- Overcast Olive CDC Comparadunyou are here
No remixes yet — make your own version.
Where this came from
“no looks about the same size try again”
fly pattern · made
0 — nothing entered the score yet, at the Derby's published weights, since . Views are not counted.
- cdc
- comparadun
- dry fly
- mayfly dun
- blue-winged olive
- bwo
- olive
- white wing
- split tail
- hackleless
- trout
- size 18