In looking a pre-game card (for a crew of three) the other day, there was mention of a hanging C. I have never heard that expression, could someone explain?

That would be a Hanging Chad, particularly applicable in Florida.

Jay R,
Center Official hangs around to help in the backcourt around FT line extended.
Unless there is a fast break, the Center official is usually slow to enter the frontcourt, and almost always pauses at the division line.

Could also refer to C staying at home base during a rotation, until L is settled, then moving up to T. This allows C to stay with post play until L can take over. This keeps L from making any calls "on the run".

I tend to think it's more likely mick's take, though.