Barter for lessons? What kind of lessons?
Perhaps you should finish law
school. If you barter for lessons in The
Bahamas, or any other Caribbean nation that is not part of the U.S. (assuming you are a U.S. citizen), without first getting all the proper permits and visas (not easy to do), then you will be violating the law and might very well find need of some
legal training.
If you are talking about bartering for
sailing lessons, then even in the U.S. you will first need to be licensed by the Coast Guard.
My advice would be to stay in school. When you are finished you will have far more options to allow you to sail and see the world.