Waterworld.

In a futuristic world where the polar ice caps have melted and made Earth a liquid planet, a beautiful barmaid rescues a mutant seafarer from a floating island prison. They escape, along with her young charge, Enola, and sail off aboard his ship. But the trio soon becomes the target of a menacing pirate who covets the map to 'Dryland'—which is tattooed on Enola's back.