Have you tried drifting your bait with no additional weight? Many times that can be productive, especially if you're in an area with a good current, which is sounds like you are. Big bass are opportunistic feeders. Many times they'll lie in wait for food to come to them on the current. Your bait won't do this if it's anchored to the bottom. Try casting up current of and letting your bait drift with the current, preferably drifting past some structure where a bass may be wating. Crabs won't bother it, and you'll cover a lot more area this way.
This is basically what you would do with a balloon rig. The balloon just keeps your bait drifting at a set depth. I've only used it with live bait, but it could work with cut bait too, if you can get it out into a current where it can cover some territory.