Nauta is a set of free miniature wargames rules for playing out ancient naval battles. The files are hosted here:
Rules: Naval
Age of Sail House Rules For Savage Worlds
Tim’s Miniatures Blog has some Age of Sail House Rules for Savage Worlds. He also has some Savage criticism of those who wrote the Pirates of the Savage Main rules.
Smoke On The Water Civil War Iron Clads Rules
I have a large collection of 1/1200 Civil War Ironclads but have never played many games with them becuase I haven’t really found a set of rules I liked. I may give theis free set called Smoke on the Water a try.
La Felicissima Armada Naval Rules
Jim Wallman offers a set of free naval wargames rules called La Felicissima Armada. It’s a Spanish Armada naval game designed to use 1/144 plastic ships on the floor.
The Battle of Lepanto Rules
The Junior General offers a set of rules — and paper ships — for the 1571 battle of Lepanto.