Many have read Patrick O'Brian's Aubrey-Maturin series (Master and Commander, et al), but his first novel is equally as good and is based on interesting sailing history.
The story follows fictional character Peter Palafox, a young Irish Midshipman, on his voyage around the world on Anson's flagship Centurian. Anson's circumnavigation began in 1740, 26 years after Parliament declared a 20,000 pound reward for any device that could determine longitude at sea but 11 years before John Harrison constructed the first workable maritime chronometer.
The Golden Ocean, though told through a fictional character's perspective, is worth reading to gain some insight into the plight of sailors before invention of the chronometer and longitude was the next best thing to a guess.