We are looking, as well. I just found this on TripAdvisor...I also posted it to our Facebook page..
Looks like there are several options that you can do on your own!
emmysdidi
We have 4 people and just booked with Capt Mike on the Fury in St Thomas 2/29. We looked at all the trip advisor reviews and this one looked great. When we booked yesterday Capt Mike informed us that he has a special price of 70 pp. They pick you up at the dock, so no Cab ride needed. Capt Mike stated that we were the first to book the morning trip, so I just wanted to let people know there was still room. Check out the reviews for yourselves. Hope to see some of you on the cruise. SR