Brian Chan's recommendation for water boatman and backswimmer:

The more numerous water boatman are grazers. The larger backswimmers are
hunting predators.

hook: heavy wire, 1X long, sizes 12 and 10
thread: black
back: PT fibers, about two dozen. strip of plastic sheeting over top
(optional)
body: dark- or emerald-green plastic chenille.
legs: Black Super Floss or Flexi Floss, threaded through the body with a
needle, held with glue

retrieve:
type III or IV full-sinking line, fast 3- or 4-inch strips. (or
sometimes just under the surface with a floating line)

I think I've caught a fish or two on a flyshop-bought backswimmer
pattern over the years, but I've never tied the fly or fished it much.

I think a Prince Nymph tied with large dark biot wings would be a decent
water boatman pattern. Maybe trim off the tail.

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