I am a big ship dork and like it from a novelty idea. I just don't see it making any money. It will get some nice traffic at first, but people enjoy the new features on ships (spa, fitness, outdoor pools, hot tubs, etc.).
Given the difficulty with funding for ships like the Queen Mary (poorly maintained right now) and the SS United States, it is unlikely it will do well over the long term even if it remains docked.
That is my $0.02!