If you want to look more at miniature rules sets then here are the ones I have picked up off of Wargame Vault. BTW they are having a sale on most of these games right now, but be quick if you want them since it ends soon.
Iron and Fire, and Blue Steel Grey Thunder; This game covers all areas of fighting.
River Wars; Focused on the Mississippi and tributaries.
Damn the Torpedoes; Focused on the southern Mississippi but can be used for all areas of fighting.
Dahlgren and Columbiad, and By Sea and By River; Both of these cover all areas. They also have a very simplified set of rules for foot troop combat if you want to do a combined attack.
Sail and Steam Navies; This game covers all areas of fighting and has the most information out of all of these games. It has a large number of ships data cards already created. Also if you want to test out other ships they have supplements of ship counters. Almost 1000 individual ships data cards can get you an idea of how detailed it is, let alone the data cards for forts and countless gun batteries.
Anaconda Capitol Navies, Anaconda River of Blood and Anaconda Naval Warfare on the Mississippi river and Gulf Coast; These are supplement books but are a great way to link several games together into a campaign.
The other sets of rules I have I found from links off of The Miniatures Page.
Smoke on the Water; This rule set covers the river and coastal areas.
Ironclad and American Civil War Naval Wargames Rules; This game covers all areas of fighting.
