I was reading the fic My Hearts Will Go On by shelwass on Teaspoon, and when I got to the end of chapter 28 I was slammed with an idea. So, this is an AU for chapter 29 (and beyond) of MHWGO, and, while I'd recommend reading the first 28 chapters of shelwass' story beforehand, I believe I've made it understandable enough that you don't necessarily have to in order to get this one.

Rose and The Doctor land in the boiler room of a ship and decide to take a look around, not knowing it's the most ironic ship of all time. Now they must team up with members of the ship to try to survive