Hans van Klinken's variation of the French Panama dry fly. With these materials, not a fly for rough water of any kind unless you like to use good dry hackle on wets.
hook -Dai Riki 320 #12
thread - Danville 6/0 grey
tail - golden pheasant tippet
rib - x-small wire gold
abdomen - peacock herl
thorax - Uni-Stretch green
hackle - brown
Part 1
mash barb, start thread; tie in rib, wrap to point above barb
trim out center of GP feather; measure (shank length), fold together, tie in/trim butts
tie in peacock herl; wrap to 1/2 mark, tie off/trim
counterwrap rib; helicopter end, cover with thread
tie in hackle