As one who did— it did not address how these would function in major sea storms encountered quite freqently. The design is called “at right angles” to wind. When in these huge waveforming storms, large vessels need to head into the wind, under power. Turn into the wind. Does not say how they can be non-deployed or stored. Perhaps it is dealt with- but it would have to be proven for the expense of not destroying a vessel. Insurers would be in the equation, of course.
“As one who did— it did not address how these would function in major sea storms encountered quite freqently.”
The article said they are retractable.
“The design is called “at right angles” to wind. “
No. That is reference to Flettner rotors.
Nice AI-generated “generic image of a tower-driven cargo ship”.
But, you see, such towers cannot drive any common container ship - the containers cannot be unloaded when a tower is installed, the tower interferes with the container cranes, the towers prevent entry into most harbors (too tall for the bridges), if installed and mounted on deck, the towers are blocked from the lower stacks of containers. If mounted on deck, no containers can be loaded in the spaces below the fixed tower foundations.
I have stood on ships while underway, their self-wind at 15 - 20 knots from the diesels driving propellers is a strong force that must pushed through by the diesel. (Yes, not the full thrust - most propeller physically is moving the hull through the water.)
Also. Center of gravity when the hull is unloaded and a sideways wind or waves is present? Capsize happened recently on North Sea ferries, car ferries, even cruise ships.
Back in the 1840s, no ship departure schedule could even be imagined until steam engines and steam paddlewheel tugs became practical. Arrival times? Unpredictable even more so.