When it comes to genre of nautical historical fiction set in the late 18th to early 19th century there are two series that are a must read. Though the C. S. Forester's Horatio Hornblower may be better known, Patrick O'Brian's Aubrey/Maturin series is at least its equal and in some ways it's superior. Both modeled their main characters on Lord Thomas Cochrane a daring naval officer with radical bent to his politics.
Though the character of Aubrey is loosely based on a real person and many of the events in the stories are based on real events, it is not all entirely accurate and there is far more action taking place during the years 1813 through 1814 than in the previous 13 years. But that's why it's called fiction so don't get too bent out of shape over it.
The real story here though is the ever evolving relationship between two opposites. Jack Aubrey, the brilliant naval commander, his world revolves around duty, ships and the sea with little understanding or patience for anything else, and Stephen Maturin, the naturalist, surgeon and sometime spy, highly educated, perfectly at home in the world of politics and intrigue, but totally lost when it comes to naval matters.
The contrast between the two characters allows O'Brian to use one or the other as a reason to explain things to the reader without having to step out of character and offers many opportunities for humor as they take their turns being out of the elements.
O'Brian brings just the right balance between action and technical details. His depiction of life in the Royal Navy during this period has been described as second to none. His writing style stays as much in character as the characters themselves with heavy does of naval jargon and period idioms that take some getting used to if you are not already familiar with them, (there are whole books written now to help readers understand what exactly it all means). After a while though you soon become accustomed to the style and it all seems perfectly natural and gives the whole series a far more authentic feel than many of the other series' in this genre.
I have one caution to give on this series though, that is to not judge the entirety of the series based on the first book in it. Master and Commander, (unlike the movie) deal mostly with Aubrey's life ashore and his rather poor attempts at courting. Things pick up once they get to sea and the series continues to improve from there. The movie of the same name is actually based on events from Master and Commander, HMS Surprise, The Letter of Marque and The Far Side of the World.