* AbilityOverAppearance: In the books, Stephen Maturin is 5'6" and repeatedly described as odd-looking, small, and "distorted", while Creator/PaulBettany is 6'3", handsome, and taller than Creator/RussellCrowe. Despite this, you'd be hard-pressed to find an ''Literature/AubreyMaturin'' fan out there who ''doesn't'' think the guy absolutely ''nails'' the little surgeon, spy, and naturalist in mannerisms and feel.
* AwesomeDearBoy: Although Creator/RussellCrowe had reservations about the first drafts of the script that he had been sent, the chance of working with Creator/PeterWeir was what ultimately convinced him to commit to the project.
* DyeingForYourArt: Jack Aubrey is supposed to be quite stout, and Creator/RussellCrowe attempted to gain the necessary weight but found that he couldn't, so the film had to settle for a captain who was only slightly overweight. Crowe and Creator/PaulBettany also learned to play the viola and cello, respectively, so that they could be filmed performing the proper bow and finger techniques. Bettany also spent pre-production learning to use period-accurate medical equipment, so it would seem fully natural in the film.
* EnforcedMethodActing: Much of the filming was done onboard the ''Rose'', a modern replica of the 18th century frigate HMS ''Rose'', which was a semi-contemporary of the real HMS ''Surprise''. All actors were given a crash course on 18th century sea-faring. Also during rehearsals, all actors were given tags based on whether they were officers or sailors. This enhanced the sense of camaraderie within each group, and made sure the actors felt that officers and sailors should not mix. Officers' actors were also given a nice clubhouse to rest in throughout the filming. Notably, Creator/PaulBettany was the only one out of both cast and crew to never get seasick (he had quite a bit of boating and diving experience already).
* ExecutiveMeddling: As said above, Creator/RussellCrowe and Creator/PaulBettany learned how to play violin and cello for their respective roles, but were dubbed over in the final cut with professional recordings.
* FakeBrit: Jack is an Englishman played by an New Zealander.
* FakeNationality: Maturin is half-Irish, half-Spanish. His actor, Creator/PaulBettany, is neither.
* StillbornFranchise: The film adaptation had nearly the entire cast signed on for multiple sequels, ''and'' they bought the actual boat they used to make sure it was going to be available. Accordingly, it was well-received critically and made enough money to be deemed a financial success, but not enough to make the sequel a sure thing, and in the end it never happened. Both Weir and the principal cast have all said over and over that they'd love to do more, but this has never entered planning stage. Weir tends to take a long time in between his projects, and he has also said that shooting a film on water is the hardest thing a director can do, so he'd really need to be sure that it'd be worth it. There's also the matter that the [[ScrewedByTheLawyers sequel rights are in a game of musical chairs]] consisting of rival studios Creator/TwentiethCenturyStudios[=/=]Creator/{{Disney}}, Creator/MiramaxFilms (now owned by Creator/{{Paramount}}), Samuel Goldwyn Films, and Creator/{{Universal}}. (the first one is exploring another way to return to the series, a prequel based on the first book)
* WhatCouldHaveBeen:
** At one point, the writers toyed with the idea of adding a love interest for Jack. Although this idea was later rejected, Creator/KeiraKnightley was first choice for the part.
** Creator/HeathLedger was in talks to join the film, presumably as Doctor Maturin. Creator/RalphFiennes was also considered for the role.
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