There is no special bass rig, it depends on where and how you are going to fish for them
One place I fish I just use a 5/0 kamasan tied direct to the end of the main line with a bunch of mussels and lower them in, this could be done off a pier.
You could also lower a livebait off a pier.
Depends if the pier has piles or is a wall. Bass hang around under a pier, waiting for food to come to them.
A ledger with three foot trace and a 5 or 6/0 with half a mackerel is also a good method for bottom fishing. You could use a big treble.
You could also just split a mackerel and lower it into the surface water and let it do it's thing, loads of oily scent, on a big hook of course, a 6/0 gets lost in a small bass of 5 lb or so.
Very simple is best, although bass are not usually hook shy if they are on the feed.