I have been to St Thomas many times as a vacation destination, but never on a cruise. I can tell you that St Thomas is rather gay friendly, and accepting. But one does need to be cautious anyway. The best bet for beach fun is to ferry over to St John...take a cab to Red Hook on St Thomas (about $10.00 per person) and the ferry ride is a short trip over to St John ($3.00 per person), and then cab over to one of the beaches. Many are secluded, and offer nude frolicing in the water.
On St Thomas, there is a popular beach, very pretty, named Magen's Bay/Beach. To the far right end is considered gay, but I haven't visited it before.
Blackbeard's Castle (not to be confused with Bluebeard's Castle...which is a time-share) is a gay hangout...although I've been told it is now considered just gay-friendly. This is supposed to be the hangout for the local gay residents, and the gay employees from throughout the island.
Charter a sail boat for the day or half-day, and most captains allow whatever you choose on board...nudity, playtime, etc.
Have a great trip.
I'll be on Triumph, and we stop in St Thomas during the same week. We leave Miami on Saturday, May 10th, and I believe that we stop in St Thomas on Tuesday (which would be May13th). Maybe you are there the same day???
My boyfriend and I, went to Solomon Bay while in St. John last Feb while stopped in St. Thomas, we both loved it, and he is from Thailand is very jaded when it comes to beaches. It is a small beach with a mix of people, but we felt comfortable. Even comfortable to loose the suites. We have talked about going back just to spend a couple of days in St. John. Its short hike to beach from the ferry, just ask for the National Park Office and the trail head starts right beside it.
I wouldn't plan on a lot of gay activities in the Islands. We have found the Caribbean tends to be conservative, even bordering on homophobic. We've had some really nasty comments made to us in Jamaica, and some time ago, the officials in the Caymans refused to allow a gay cruise to disembark there.
Have your gay fun in Ft. Lauderdale or Miami before and after your cruise.