Corrected entry: After launching the decoy "vessel", Capt. Aubrey shouts, "Hard a-larboard", spins the steering wheel to the left, making the ship turn left. But in those days a ship's wheel worked in the opposite way: to turn the ship left you had to spin the wheel to the right, and the correct command would have been "Hard a-starboard."
Corrected entry: Stephen Maturin's cello has a end pin or spike which he rests on the floor while playing. Cellos of that date did not have such spikes, they were cradled between the legs of the player.
Corrected entry: In the scene right at the beginning, when the midshipman who later commits suicide spots the strange French vessel on the horizon, the other midshipman present refers to him as the "officer of the watch". However, no one below the rank of lieutenant could be in this position.
Corrected entry: The scene were Captain Jack explains the difference between a pirate vessel and a privateer was solely to educate modern audiences on the matter. It was a common practice at the time for a government at war to authorize private vessels to prey on ships of the enemy (so common that the constitution of the United States specifically authorizes the government to do so).
Corrected entry: The title of the movie is "Master and Commander", describing Jack Aubrey. But Jack is not a master (technically speaking he isn't a commander either, but a post captain.) He would only be the 'master and commander' if he didn't have a sailing master on board, but he does have one on the Suprise in the movie- the man who gets shot through the forehead when boarding the Acheron, after saying that "the job is done".
Corrected entry: In the navigation scene, the midshipmen and Capt. Aubrey are facing the wrong direction: The ship is south of the equator, heading south. The sun should be north of them, but all are facing forward to "shoot the sun" with their sextants. Note they have to turn about, to see the Acheron pursuing them.
Corrected entry: Most of the views of the French privateer Acheron were computer generated imagery (CGI) from a digital model of USS Constitution. A Fox crew spent several days in Boston photographing and using laser measuring instruments to capture a complete and accurate version of "Old Ironsides."
Corrected entry: In the opening scene, the officer of the watch and Aubrey couldn't even spot the French ship with the telescope through the thick fog. But then, how was the French ship able to fire at Surprise with such accuracy? Their line of sight would be just as bad as the British.
Corrected entry: The Captain and the surgeon play several duets together, with the Captain on the violin and the surgeon on the cello. However, if you listen closely to the songs they play, many of these sounds couldn't actually come from a duet. Most notably the first time they play, it sounds more like two violins and a cello, or even a string quartet are playing the song, when it's showing only the two men playing.
Corrected entry: It is a great idea to use the fake navigation lights. But no ship would even have them lighted during a chase in the first place.
Corrected entry: Midshipman Lord Blakeney gets his right arm amputated. Two scenes after that you see his right arm back, holding a sextant.
Corrected entry: When Aubrey gives the boy a book on Nelson, the boy asks about a certain battle and Aubrey tells him it is on a certain page. In 1805 and before, most books did not have page numbers, or those same numbers were incorrect. He's much more likely to have used the printer's signatures or just have flipped through the book to the correct page. I'm not saying he wouldn't have had a book with numbered pages (or those pages wouldn't have been correct), but Aubrey would likely have been in the habit of NOT using page numbers.
Corrected entry: I don't know whether this is an editing error or a projection error, but several times during the storm scene, mysterious patterns of colored lights (perhaps a camera graphic) briefly flash up on the screen for a frame or two.
Corrected entry: During Stephen's self-performed surgery, he asks Higgins for the catling. This instrument, a long, sharp, double-edged knife used for amputations, is not what a doctor would have used to make his initial incision and it is not what Higgins hands him in the subsequent shot. (01:30:55)