Sado said:
You can look at Skull and Bones from Green Ronin. I don't have it myself, but I know they put out good stuff. It is set in that time period but with fantasy elements.
I've got it, and I'd recommend it highly. The rules for gunpowder, muskets, cannons, and sailing are all as realistic as you can get without sacrificing gameplay. The method for crew vs. crew combat is very handy.
It's actually set a little earlier than Napolionic Era, but Naval Combat didn't change so much that the rules wouldn't work well.
Gareth-Michael Skarka of Adamant Entertainment and author of
Skull & Bones also posted on the Adamant Entertainment messageboard, "The supplement is called CORSAIR, and is a compilation of the ship rules from S&B, the advanced ship rules from B&B, and a bunch of new material (such as new ship types, new customization options, new ship feats, etc.). That'll be out right after FVLMINATA D20."
If you can wait for it, it looks like
Corsair will have everything you're looking for and nothing you don't need.