Master and Commander does for early 19th Century naval warfare what Saving Private Ryan did for D-Day. It is gritty, nuanced and spectacular without being forced. It never plucks the wrong note. It doesn't beat you over the head with plot twists, or overplay its dramatic crescendos. It is a sea adventure without swashbuckling cliches. It is Moby Dick without the whale, and Pirates of the Caribbean with a "ghost ship," but without the camp.
One of the beauties of Master and Commander is it doesn't play politics. It makes no attempt to be contemporary and relevant. It doesn't sermonize about war being hell or the evils of imperialism. It is simply about a crew of seamen who have a job to do — a bloody and ugly job, but it is nonetheless their job. If the movie teaches us anything, it teaches us that in 1805, the seafarer's life was brutal, hard and treacherous. Survival depended on strong leaders, but stronger men.
I've never sailed on a big ship, so call me a chickenalbatross if you like, but I have little doubt that life aboard a ship in His Majesty's Navy was much like it was in this movie. Or at least movie sells the idea well enough that from the start the suspension of disbelief necessary to good drama is at full sail.