I agree with Art. I've been to several of the lesser antilles, mainly Antigua, and befriending the locals is the best choice.
Once they know where you fit in to their framework, you will have a much better time. Respect them as equals, and more than likely they will open up and show you the spots the locals go, and warn you where not to go. Travelling with the locals is the safest approach, of course. Don't jump out of your seat when the driver blows their horn and waves to everyone. I think it's the Antiguan Greeting..two beeps..

Am_Fear_Liath_More: I have known several charter boat captains and owners in the lesser antilles, some for 20 years. There is piracy and kidnapping occurring down there. It's not publicized like the piracy in the waters of the mid to far east, but it does exist.
From what I understand the heyday was during the 1980's when boats were used to move drugs into the US. Apparently Mexico is carrying that buden now, as boat thefts have dropped. Of course, hanging a few people didn't hurt either. And it's easier to hijack a running boat in the ocean than to sneak into a marina, find the hidden kill-swiches for the fuel pumps, start the boat and get out of dodge before the locals decide to feed the thieves to the props.