A detailed naval wargame involving the earliest armored steamships and wooden warships of the era, Ironclads has clear rules and lots of flavor. The game simulates American Civil War naval actions, 1862-1865. The scale is 100 yards per hex, 3 minutes per turn, and the game features simultaneous plotted movement. Ship-to-ship communication is (nearly) out of the question, and this can make for misunderstandings and collisions. Combat involves gunnery, ramming, and spar torpedoes. There are quite a few charts (after a few games, they become quite easy to use) and a lot of dice rolling.
Still the best board wargame that covers this subject. Not a perfect simulation (e.g., gunnery is notably more accurate in the game than in history), but a terrific game.
A 2nd edition of the game is currently available with the Excalibre 2nd edition making a number of corrections to the original as well as featuring much improved physical quality, production value and graphics; making an outstanding and classic and great game even better.