Yeah it’s a terrible idea, airships barely work as camera platforms cum billboards. But sails aren’t just windbags, they can function as airfoils to provide power in directions the wind isn’t blowing. I’m exactly one episode of Mythbusters curious about it. I remember going to a hockey game and the stadium had a remote controlled blimp the shape of a Coke bottle that would fly around the arena, I’d like to attach rigging to one of those and contrive a 5-6 mph wind scenario to see if it can do anything other than go downwind under sail.