I've tied crab patterns before but they never seem to swim the right way up, so now I'm hoping I've cracked it with this pattern. It has a split shot glued Clouser style to the hook shank to make it swim point up. Anyway hope you like it :)
Cheers Dave
Hook: Sakuma 410 2/0 with split shot glued to shank
Shell: Brown Furry Foam
Legs: Craft Foam cut into strips heat bent and coloured
Eyes: Nylon Braid dipped in UV Gel and coloured black nail varnish
Mouth Palps: CDC
Claws: Cheap brown hackle trimmed and stiffened with SH
In the pic above you can just see the split shot, coloured green.

David,
David,
Very nice looking fly!
The key to get a fly to ride hook point up is not always weight, but rather a "sail" or "rudder", which points up. The wing on a Crazy Charlie or Gotcha it a good example.
This will act as a guide to the fly as it sinks, much like the tail on a kite in the wind. So making sure your flies aren't flat, but has most of its extensions - like the crab claws and legs - pointing upwards, might do the trick.
Martin