Pete Pellegrino has written a set of free miniature wargames rules called Damn The Torpedos. In the game, you customize your ironclad, and then take it out to fight in the Cvil War battle of Mobile Bay.
ironclads
Heart of Oak, Skin of Iron
Heart of Oak, Skin of Iron is a set of free wargame rules for naval combat in the years 1852 – 1870.
A Hotter Fire ACW Naval Rules
A Hotter Fire is a set of free wargames rules for naval combat between civil war ironclads.