I have used Bonine a few times and it's good stuff. Ginger is great too, but the secret is to begin taking the ginger at least a week prior to the cruise. We actually treat ourselves to crystallized ginger instead of pills or powder. Candy is always better than "medicine".
I almost always ask for ginger after dinner during the cruise. It isn't quite the same as the type I have at home, but it seems to work. Good luck with whatever you try.