"In the cases that I can think of where seacoast batteries of heavy artillery were easily overcome it was typically as the result of early war naval gunnery and often surprise combined with poor placement of CSA guns, logistical problems, lack of proper ammo, etc. In several cases siege was a major component or the battery was essentially outflanked."

The Confederate lack of naval power keeps showing itself as I read of the engagements you mention. This weakness was a particular debit on the rivers, where whole Federal armies were positioned with rapidity and offensive (indirect) cover fire available on short notice to the invaders.

The ability to match production of the tools of war with the North was lost early in the contest with the losses of the City of New Orleans and those areas of Tennessee that were manufacturies. Sherman honed his tactics of economic destruction in the Tennessee Campaign that were later used on the grand scale of destruction that was the result of his forces march through Georgia.