The website Three Decks, says it "has become a premier resource for researching naval history during the Age of Sail." Even a quick glance at the home page leads one to believe that statement is true.
There is much to explore, notably the ability to search for ships, battles, and people. If you have an ancestor who fought with the Navy during the time of sailing ships, this site it worth checking out. You will certainly get some valuable background information, and you may also find him by name.