From the name of this film, you might think that Master and Commander is some kind of dominatrix-fetish, S&M fantasy flick. You would be wrong. Instead, this is a film loosely adapted from Patrick O'Brian's series of novels chronicling the fictional adventures of Captain Jack "Lucky Jack" Aubrey and his doctor-friend Stephen Maturin during the Napoleonic Wars.
Having never read the books, I didn't know what to expect, and ended up being pleasantly surprised. I enjoyed very much the give-and-take friendship of Aubrey and Maturin, and was glad that fully-realized characters were on-screen as opposed to one-dimensional cut-outs standing in front of the action. Even the lesser players in the film are given a nice level of characterization... including an officer the crew believes is a "Jonah," cursed to bring the ship misfortune, and a young boy who loses an arm but not his spirit in battle.
The action in Master and Commnder is all at once breathtaking and horribly confusing. The broadside battles are really cool to watch, and the brutality of such warfare is captured in detail. But, when it comes to the massive hand-to-hand conflict at the end, it's nearly impossible to tell who is fighting who, and everything degrades into a bunch of anonymous fight scenes that really detach the viewer from the story. If directory Peter Weir had bended historical accuracy a bit, and tried to find a way to better differentiate the opposing forces, I think it would have made for a stronger ending.
Overall, a good historical action film that doesn't suffer from lack of characterization, and is worth a look despite some confusion near the end (and the fact that "Pippin" from the Lord of the Rings films is the ship's helmsman didn't help matters... "Where's Frodo, Sam and Merry?" I kept wondering). I will probably give the Patrick O'Brian's source material a read to see if it holds up as well.