Beginner’s Fly Tying: Light Cahill Pattern

By Don Fine

As noted in our earlier Streamlines newsletters, the theme of our 2020 Beginner’s fly tying program is to focus on improving basic fly tying skills for the correct application of materials on the hook. Increasing in complexity from our last class in February, the Light Cahill wet fly builds upon the skills we’ve learned so far, which included the correct application of a tail, hackle collar, and wing to the fly. The Light Cahill is a great general imitation of summer mayfly duns. While the Light Cahill was originally designed to imitate a family of mayflies with the name of Stenonema, it is a great searching pattern that can be used to imitate light colored mayflies which begin hatching in late May and continue through June.

Here are the photos we received from members for the April tying session:

Nina Cleven's Light Cahill
Andy Mekelberg
Andy Mekelberg's Light Cahill
Jamie Barton
Jamie Barton's Light Cahill
Martyn Holland
Martyn Holland's Light Cahill
Tim Gibian
Tim Gibian's Light Cahill
Troy Kitch
Troy Kitch's Light Cahill

Instructions and Video

We are happy to report that 20 people signed up to participate in this “Fly Tying at a Distance” event!  Now that you have your tying material, here are our instructions and demo video for the Light Cahill Fly.  Once you’ve completed this session, consider  sending us a photo of your fly and/or you at the vice to — we’ll post all of the photos we receive on the website!

*The following tying steps and technique are quite standard for tying many traditional wet flies. See also notes at the end of this set of instructions.

Materials required:

  • Wet fly or nymph hook – size 12-16
  • Tan 6/0 thread
  • Cream or Tan dubbing
  • Cream colored saddle hackle
  • Mallard flank feathers

Tying steps:

  1. Place hook in vise after crushing down the hook barb.
  2. Start the tying thread close to the hook eye and wrap thread toward the hook bend, stopping directly above the hook barb (i.e. at the start of the hook bend).
  3. Select one of the light colored hackle feathers (not the mallard flank feather). Holding the fibers at 90 degrees from the feather stem, and either cut or quickly strip a small bundle (~8-10) of fibers from the stem.
  4. Measure the length of the small bundle to equal the straight section of the hook shank.
    • Assuming you are a right handed fly tier, hold this small bundle on your left hand, such that the bundle extends beyond the bend, with the tips to the rear.
    • Before beginning to tie in the feather fiber bundle, hold it somewhat to the side of the hook as it faces you. Then make one thread wrap around the small bundle of fibers. Note that the thread pressure brings the bundle up to the top of the hook. (Consider practicing this step before proceeding, once you have mastered this skill, it will come in handy any time you are adding a tail to a fly). If so, continue to make additionalwraps forward on the hook. Then make wraps toward the rear (bend) of the hook stopping where you first tied in the hackle fibers. The previous step should hold the tail fibers firmly in place and returns the thread to the location for the next application (i.e. dubbing) of material.
    • Before beginning the next step, cut off the excess hackle fiber butts which are facing toward the hook eye.
  5. Apply a small amount of dubbing to the thread which now should be hanging immediately above the hook point. Remember application of dubbing to the thread should be done by pinching (a small amount) of the dubbing between your thumb and index finger, and twisting the dubbing onto the thread in only one direction (preferably in counter-clockwise direction on the thread). (I suggest you practice this step several times until you feel that your skill has improved enough such that the dubbing noodle is tapered on the thread; thin at the start, to thick in the middle, to thin again at the end of the noodle).
  6. Once the thread is dubbed, begin wrapping the dubbing on shank of the hook forward toward the hook eye. Stop approximately 1/4” behind the hook eye and making several more wraps in place to secure the dubbing at this point. A space of ~1/4” should still remain behind the hook eye.
  7. Remove another small bundle of hackle fibers, which will comprise the “beard” of the fly. Measure the length of these fibers to extend rearward toward the point of the hook (i.e. approximately ½ hook shank length).
    • Hold these fibers on the far side of the hook (away from you) and make one or two wraps of thread around the hook shank. As you make these wraps, by applying downward pressure on the tread bobbin this will bring the hackle ”beard” to the underside of the hook. Make several more wraps forward.
    • Trim off the excess (butts) which are sticking forward.
  8. Then select a mallard flank feather (for the wing of the fly) with good symmetry (roundness at its tip).
    • Then while holding the stem of the feather in your right hand (for right-handed tiers), stroke the tip of the feathers down such that you can “measure” their length, while holding the feather above the hook. The length of the mallard feather wing should be approximately the length of the hook shank.
    • While holding the feather in your left hand, trim off the excess butts of the feather. Then move the feather section, which you are holding, to that section of the hook where your thread bobbin is now hanging.
    • Then while holding the feather tightly against the hook begin to wrap the tread around the (wing) feather bundle. It is critical that you use the “pinch wrap” technique. (Hopefully you will recall that the pinch method requires that with each wrap of the thread, you pull directly down on the thread bobbin toward the tying table. This applies the thread pressure directly down while holding the wing tightly on top of the hook shank).
  9. The fly is almost finished, except to make several additional thread wraps which provide a smooth head on the fly.
  10. Whip finish or half-hitch finish the fly and cut the thread. A light coat of fly cement can be applied, albeit this is not necessary if the finishing knots are secure.

*Notes for Consideration:

As with any new fly pattern, each repeat will improve the appearance and correct representation of the fly. Also YouTube and other videos provide alternate methods for tying the light cahill and other wet fly imitations. Remember: the focus of this sequence of tying instructions is to learn proper techniques for fundamental fly tying. While methods of tying differ from instructor to another, in  tying any artificial fly, the end result will be the same (a good representation of the pattern) if proper tying techniques are used. 

About our Tying Sessions During COVID-19

As we all are aware, the COVID-19 pandemic has disrupted our respective lives beyond imagination. You might say this virus has infected our recreational outlet, in that our club had to cancel meetings, fly tying sessions, and even fishing outings (as an example, I am unable to fish with a dear friend next week). We can rejoice, however, in that the leadership of our PVFF club has been hard at work developing work-arounds for some of our regularly scheduled events. But Good News! While we had to cancel the beginner’s tying session in March, we will continue this program in April ‘in abstentia’ or FTAD (fly tying at a distance).

Thus, the beginner’s fly tying program for April (and beyond) will continue as follows. For those of you who wish to tie the March fly pattern, sign up on the club website for the session (at least a week) in advance. As an example, because our beginner’s tying sessions are generally held the third Monday of each month, the sign up would be before the second Monday of that month. Using the website sign-up list, we will then know who intends to participate in tying the ‘fly of the month,’ allowing us to prepare enough packets for mailing the respective materials to you. Written instructions for a given month’s fly pattern, and hopefully a tying video for that fly, will be available on the club website for your use.