True with respect to cargo ships but there are still millions of sailboats and yachts plying the waters around the world today. Not sure if anyone has actually disproven the use of cloth sails to augment diesel or turbine power, versus just an emotional choice for the Flettner rotors since they seem less disproven, being unusual. Has any modern cargo ship just tried adding a few regular unpowered, cloth sails? Has there ever been an A/B comparison of the 2 models of same ship, with one adding flettner rotors, and the other adding some cloth sails, seeing which works better, or whether either is truly worth bothering with in the modern world?
Or do cloth sails lack the “pizazz” and perceived novelty of flettner rotors, being seen more as “yesterday’s news”? Remember, Professor Crackpot never sleeps, and in this era of “Global Warming Derangement Syndrome”, many people have abandoned common sense, and are instead driven by emotions and slogan-based “reasoning”.
Not to mention “Greenwashing”. If a large corporation is providing shipping around the world, by which billions of people benefit, yet are castigated for sole responsibility for some resulting emissions, it is understandable they should waste a small percentage of revenue on “greenwashing” symbolic supposed efforts to comply with the bumper-sticker-level “thinking”, so they can point to some noneffective box-checking symbolism “project”, to receive more lenient treatment by the manipulative and money-grubbing corrupt “authorities” that thrive on making the fulfillment of simple needs, like transportation, difficult or impossible.
It can then be said “Well, at least they are TRYING”. This is how any “command economy” swirls down the toilet bowl, as symbolic obedience to the illogical demands of the tyrannical rulers increasingly replaces economical reality, until complete paralysis eventually results.