I would argue that if you're not already intimate with sailboats (i.e., nothing under 42' is likely to have room to install a washer/drier in the conventional sense) and the associated maintenance and update they'll need...You residency will consume all of your free time and you'd be better off buying into distressed Florida real estate (condo or home) and letting it appreciate as you finish, then using it either as a home or a great way to pay off med school bills.
Vacations? holidays? do residents get much of that? I'd expect a used boat to swallow up any free time that you might get as a resident. It could be a lot of fun, yes, but the odds are it would be exhausting--and that's not a good thing in the hospital OR on the water. Better to invest in a condo, and charter a boat for fun. (And that's from someone who doesn't believe in condos, but upkeeping a home might also be one more thing you don't need to be distracted by.)