Some very effective flies like the CDC and Elk, the IOBO, and the IOBO Humpy require CDC. CDC is such an integral part of these flies that nothing else will perform as well. The IOBO and IOBO Humpy are so easy to tie that I can't see using a substitute. When the fly is done; save it, cut the materials off and us the hooks to tie up more.
These three flies go back to the very early days of the internet before the World Wide Web and Netscape Navigator. Fly fishers all over the world communicated by email using Flyfish@, a worldwide mailing list. The lack of images led to some interesting discoveries. Hans emailed us his directions for tying the CDC and Elk. No one in the USA tied with or knew about about CDC before Hans introduced it to Flyfish@. You need to understand that no one had a photo of the CDC and Elk before the WWW. All we had was the Flyfish@ mailing list, in which a description of how the fly was tied was emailed to each member. Think old school type written instructions except you read them on a monochrome computer screen. No graphics except what you can draw with ASCII characters. So although Hans described how the fly was tied, we could not actually see how it was tied.
There is a bit of serendipity in all this because, members tried to duplicate the CDC and Elk. One of our members, Jack Tucker, tied up what he thought was a CDC and Elk from Han’s directions. It was a killer fly. It was later discovered that Jack’s fly was not a CDC and Elk at all.
It was not until the The Flyfish@ dry fly swap that members saw the CDC and Elk tied by Hans himself. The swap page can still be found on line and is still maintained. It can be found here.
Complete Dry Fly Swap
The CDC and Elk is on this page at the bottom right.
Section One of Dry Fly Swap
Once Jack realized that his fly was NOT a CDC and Elk but an effective fish catcher, he called it the IOBO for "It Ought to Be Outlawed." From that fly was spawned the IOBO Humpy. Although it is not as well know as the CDC and Elk, the IOBO Humpy is a pattern that has caught many a trout for members of Flyfish@. Hans has put both the pattern and a video up on the WWW.
The original IOBO is basically a single type 4 CDC feather wrapped around the hook with the tips forming the upright wings.
IOBO Humpy