Well, they don't call them "arks" for nothing. ;)

Really, they do throw you off in the beginning because Woody Harrelson's conspiracy-theorist-radio-DJ character, who's been right about everything else, calls them spaceships so when the other characters call them arks you think, "Oh, in a Wall-E or BSG way," but, no, they're just big boats.

Thanks. I'd never even heard of her before that, but she was so damn adorable I couldn't resist. :D