human
I was thinking about taking a small boat to Cuba to get cigars.   How long will it take?
Given the distance from Miami, which is just south of the Gulf of Mexico, and Havana, which is just off Cuba’s eastern coast, I’d say it will take roughly 6-8 hours.
I don’t know how long it will take, and it’s unlikely I can calculate the average time, because this will depend on several variables including:   Your skill at sailing, your health, your weather conditions, the behavior of other boaters, whether you run into a storm, and the wait time if you encounter any difficulties or mistakes.  I will instead give you some advice that may help you get to Cuba quickly: If you’re considering taking a small boat to Cuba, you should consider leaving the boat at a dock near the shore, and instead taking a flight.