I actually posted another comment, previously in this story's discussion, mentioning high-altitude kite propelled container ships. You'd probably still need to burn something (or somehow otherwise) turn screws for maneuvering and propulsion in coastal waters, but that's a small fraction of the fuel burned each crossing.
No even with kite propulsion cargo ships will still need to run the main engine constantly. Wind just isn't strong enough to push a huge ship through the water a reasonable speed using a relatively small kite. See the other link in the sibling post; total fuel consumption with a kite is only 5% lower.
There are practical limits to kite size in order to keep them controllable. And where would you put multiple kites? Deck space is at a premium and they won't sacrifice cargo capacity.
