Going to try a new type rig.
I got some 20mm polystyrene balls to create a 'popup' rig.
Using a normal rig,but having the hooklength weighted about a foot from the hook.So the bait is up above the reach of the crabs.
It will also keep the bait out of any mud or junk on the bottom.
I've had days where the crabs made fishing a waste of time.
If the seabed is muddy or full of silt,the bait should be just above it.