DON'T DO IT!
We were in Fort Lauderdale this past December-January holidy season. You can fly from FLL or MIA or WPB to Nassau for a lot less money and aggravation than this old rust bucket ship they call Discovery. Case in point.... owner of guest house we stayed at told us that often, the Discovery stops in the middle of the Atlantic Ocean to pick up Cubans, Haitans, or whomever that are trying to drift to America. The three-hour cruise often turns into a 5-hour ordeal and the old ship has no stabilizers and in rough seas, is very rocky. I turned green just hearing this horror story from somebody who sailed it once and swore never again.
Hope that helps.