Harriet! You don't have to go without health insurance in the Bahamas. It's actually far less expensive for far better insurance as long as you're not in this screwed up country.
Check into this:
http://www.marinecrewinsurance.com/
I was covered by a Lloyd's of London insurance policy, as was my wife, while we crewed. It was extrememly inexpensive and even covered things like childbirth. If you are outside the US for a certain period (I forget how long - the policy will say), you can be covered for pennies on the dollar.