Carry On, Mr. Bowditch, by Jean Lee Latham

I was at a bit of a loss to tag this book. It's a somewhat-fictionalized biography of Nathaniel Bowditch. Since all of the dialogue, however plausible, must have come from the author's imagination, I'm tagging it as nonfiction and based on a true story; take your pick!

The story starts with Nathaniel as a young boy, a few years after the start of the Revolutionary War. He lives with his parents, grandmother, and siblings in Salem, Massachusetts. His father was once a famous sea captain, but after losing his ship he lost his taste for sailing.  Now he works as a cooper, but struggles (and sometimes fails) to make ends meet. Nathaniel is a talented student and excellent at mathematics, and the community has high hopes for him to attend Harvard and be a credit to Salem.

However, fate has other plans for him. Unable to feed his family, twelve-year-old Nathaniel's father apprentices him to a Ship's Chandler as a bookkeeper for nine years. Nat is devastated, but he knows that he has a responsibility to take care of his sisters, and part of that responsibility is to never let them worry. During his time in the warehouse, he learns all about the various tools and parts that go into outfitting a ship. He also makes use of his apprenticeship to study navigation. But in order to learn thoroughly, he needs to study volumes that were written in other languages. And the only way to do that is to actually learn the languages (primarily Latin and French). Although he never makes it to Harvard, he is invited to be an honorary member of the Salem Philosophical Library (in other words, he is permitted to make use of the library without paying the subscription cost). Many of the quality volumes were taken as a prize by a privateer during the war.

After completing his apprenticeship, Nathaniel is offered a position as a clerk on a ship captained by an old friend. Having no other obligations or options, he decides to go, as well as invest his savings in freight that he can hopefully sell at a profit. During his time on the Henry, Nathaniel is able to put his theoretical knowledge of navigation to practical practice. And thus begins the fascinating story of the man who wrote one of the most foundational books in ocean navigation, hand-checked many of the numerical tables used at the time, and created new methods for more easily calculating longitude. He did an amazing job of using every talent he was given to create a fascinating career, and to help others benefit from his knowledge through his publications and in-person instruction.