One doesn't need rockets to make it sea worthy. But I would hope for that over making it "air worthy." But a ship like that as old as it is would need constant human attention. After a nuclear war it would be nothing but it's metal bits. But then again we are dealing with the "Just because" style of writing.
It was an attempt at humor. Of course in a world that was Fallout before the war people would be as patriotic as ever and would go to see it, even without rockets