Start on Sunday with the Welcome to St. Thomas Island Tour and Sail abord the catamaran, Spirit of St. Christopher. www.treasureislecruises.com/adenture/VIExplorers/viexplorers.html
For $55 each person, you get a tour of the island in an open-air safari, all you can eat picnic lunch, the sail, the snorkel gear, instruction if you need it, beautiful area in Chrismas Cove on Great St. James to snorkel, all you can drink rum punch when you are done in the water, the sail back, then finish the island tour in the safari...all for $55. That's a great way to get started. After that, if you want to do another full day excursion, there are many, many to choose from that can accomodate 16 passengers. So many that you can pretty much just open the phone bookand pick on and it'll be great. There are some sailboats that are "6 pac" (six passengers only) but they are usually advertised as such. A personal fav of mine that would work for you would be the New Hosizons (www.newhorizonsvi.com/).

Have fun!!