Majestic Twelve Games has set sail and released the 3rd edition of their Grand Fleets rulebook. All aboard for high seas naval warfare. The game covers oceanic combat from the late 1800s with its Ironclads all the way to WWII and the floating cities that were the Battleship and Aircraft Carrier. And it doesn't just cover fighting directly on the water, the rules also cover submarines and aircraft, as they were just as important to the conflicts.
The advanced rules of the game add in extra realism with guides for using radar, smoke screens, critical hits on ships, morale levels for your ships, fighting at night, and destroyer flotillas. The scale of the game is up to you. Distances are given in kyds, letting you basically just decide if you want that to be a couple inches or a couple feet each. Added flexibility comes form the comprehensive guides for making any specific ship you can think of during the time period. So you don't have to worry about memorizing a hundred charts for a hundred different ships. You can just make up your own.
Still not convinced? Well, you can download a free version of the basic rules from their website. If you decide you like them, you can go back for the full rules.