They're just slightly improving the efficiency of a grossly inefficient system. When wind becomes the dominant propulsion force, then it becomes appropriate to

They're just slightly improving the efficiency of a grossly inefficient system. When wind becomes the dominant propulsion force, then it becomes appropriate to start using terms like "wind-powered". As-is, this is just PR. These vessels burn copious amounts of awfully dirty bunker fuel with basically zero emissions control systems. If you've spent any time downwind of such ships, you would better appreciate how offensive the green-washing of this relatively minor improvement really is. Just sailing downwind of a cruise ship idling at port is noxious enough to make one nauseous, and it isn't even under load. The whole industry needs a hard reset in the emissions department. Basically any commercial transportation venture traversing international air/seas operates in a regulatory void and takes advantage of it wherever possible, at the expense of the planet.