I generally use a 1/0 Standard hook.
Dumbbell or bead-chain eyes(very sink rates)
Dark green thread
Legs-Peacock Herl
Flippers-Tan Saddle Hackle(scraps)
Eyes-50 lb melted mono.
Body- Green w/flash Synthetic Hackle, I’ve found several names for this, basically its fibers wrapped into a twist of wire, the fibers should be about 1”- 1 1/4″ long.

Start by grabbing you Tan saddle hackle and find 4 feathers that you’ve already taken the long tapered tip from(recycle/use up the last bit of material!), this will be used to make the flippers, be sure to get the angles right, and place the feather so they’re all relatively flat to each other, I like to use this stiffer squared off feather because it is more durable, and delivers more profile with less material.

Next a single strand of peacock herl and ty 4 half hitches in it as evenly spaced as possible, starting at the bend end of the hook. wrap on one end of the herl at a time, it should make a loop. repeat this with another herl, then repeat with two more strands at the eye of the hook. The loops should not be cut open(allowing the legs to form) until after the body is trimmed(last steps) it’s just easier to tie it that way!

Melt a piece of 50lbs mono until you’ve formed an eye approx. 3/16” dia. repeat this and form a second eye. If your practiced at melting mono eyes, I recommend using a single piece and carefully melting the eyes to 3/4” - 1” apart and then folding it to a 90 Degree and(use pliers to give it a good pinch). (Using a single piece is just that easier at the vise.)

Attach the mono eyes so they’re spaced evenly with the legs and slightly angle towards the hook point, as this fly rides point-up.

The dumb bell or bead-chain weight is place directly on top of the mono, or just in front of it, (this is when you might make variations, think about where it could be used, is there a lot of current/tide? is it shallow or a deep cut along the shoreline?) The Craba pictured has a medium dumb bell just in front of the “middle” of the fly.

Now tie on the synthetic fiber-wire so it can be wrapped/dubbed towards the eye. STOP! if you haven’t already added glue or head cement this is the time to coat the shank and give it some strength! After your cement is dry(or tacky) wrap the wire towards the eye, I us my fingers to “brush-out” the fibers away from the shank, to get the most from them. Be cautious when wrapping the body not fold the eyes, or catch a leg. I hide the weight.

If a weed guard is needed add it now, if not whip finish it and glue your head.

TRIM the body first, then cut the leg-loops open so they can articulate freely.

If you tie it Larger you could add details, or give it some orange crystal eggs, I had white/pearl ladies nail coloring and if only I could find it would attempt to color the belly/bottom side of the crab, not sure how the stuff will hold to this fiber though…