Suz... we did a Buck Island sail and snorkel a couple of years back. We were two families totalling nine people, and had a sail boat to ourselves, and the ship's mate acted as an underwater guide as well. It was terrific!
I am wondering if you are speaking of the same Buck Island trip we took from St. Thomas. If so, it was GREAT. We were first timers and now we are bitten by the bug. We had a lovely sail out to the island, a marvelous time in the water and a relaxing trip back to the ship. We went on the morning run and they also have one in the afternoon. Six people on the boat. If you go do not forget a camera for underwater. The crew and the dive were the best. Good luck and enjoy.