Highly recommend Black Rock Sailing School. They are based out of Boston but do school of CYOA in St Thomas. I did my ASA 103/104 in April of this year and could not have asked for a better course. We trained on 49 Beneteau. There were 3 students to one instructor. It was like being on a bareboat charter for a week but included instruction each day along with practicing skills. We got to visit St John, Norman, Sopers, BEYC, and JVD. It was my 6th time in the islands chartering and learned so much. I'm looking forward to doing more courses with them in the future.