I was guessing that you probably were in TB but just wanted to be sure to warn you if you weren't. I did it once from Negril to Frenchman's but never again!
You might want to check out http://www.captain-dennis.com/ Captain Dennis if you don't already have a boat connection. He is an old acquaintance and good operator. You can sometimes see the manatees at Alligator Pond and a little more up the coast is a place called "Gut River" where a blue hole wells up from the ground and flows toward the sea. BTW, "Gut" actually comes from the Germans saying "Good".
Peace and Guidance