I’ve done a lot of reading on the topic itself over the last few months, and I really like it. Cargo vessels that are powered by the wind. All modern cargo vessels are powered by conventional fuel sources, and I believe only a handful of commercial fishing vessels are under sail. There have been several attemps at building and deploying sails that are really gigantic kites on cargo ships, as sort of a bolt-on solution, however there would be a large amount of computer control required because of the complexities of wind at such a high altitude.
NewsDaily is carrying a piece on a new Sail powered vessel. One of the biggest impracticalities is the extra cost in building the ship itself, as well as concerns that a drop in fuel prices might make it even less practical.