Lost at Sea: The Search for Longitude

It's pretty engaging and has a lot of cool interesting anecdotes and drama. A bit technical design is presented and it's for sure worth a watch and a much easier intro to the story than the more complicated book/audiobook. But it has the hectic and random style of the book it's based on so you kinda get a ton of facts about a ton of different stuff and it can be a bit hard at times to understand the basic story or the simple design. For example, how can I understand how a clock works without a detailed intro? Then you also need to understand the historical setting, the politics of the time, John Harrison himself, the wood and metal they could produce, the ship fleet, how universities and design worked, how the prize fund worked, how navigation worked, death rates, clock sellers and much more. It's fun either way, of course, and you'll enjoy it.

It's a lot to take in so you won't quite understand it all, but you will get a short intro. I do recommend watching more simple intros too like BBC's "The Clock That Changed the World". Then after you have done that you can read the book.