Important note: Pirate Latitudes was published posthumously. There's a very good chance that this story wasn't finished, and the writing shows that: the dialogue is a bit contrived, the plot is cliche, and the writing itself sounds unedited (especially at the end). Though Crichton's other novels were acclaimed, this one definitely falls short. 
 That said, Crichton did some research for this novel, and that shows in his descriptions of settings and explanations of nuances (such as the difference between a privateer - who pretends to be official - and a pirate - who just steals). The research was interesting and I've always loved a good pirate story. While I'd hesitate to call this novel good, it was readable - just don't let your expectations rise too high.