Pirac.io is another awesome ocean/ship battles type io game. You cruise around in your battleship collecting gold from the sea, and fighting off pirates. Or you could be the pirate yourself!
How to Play Pirac.io
To play, you simply use your cursor to guide your ship, and left click to fire. Collect gold to buy cool upgrades for your ship too.
The best strategy is to pretty much avoid combat until you collect a lot of gold and become powerful enough to take down larger enemies.