Good news on the “weird turning-metal column effect” front: they just installed five tilting rotor sails on a newlybuilt bulk ore carrier.

https://gcaptain.com/newbuild-vale-vloc-revealed-as-bulk-car...

Why is this important? It shows that the ship owners has seen enough promise in the technology to overcome the potential risks. If it works out well for them we will very likely see wider adoption.

From that article:

"If the pilot proves effective, it is estimated that at least 40% of the fleet will be able to use the technology, which would result in a reduction of almost 1.5% of Vale’s annual iron ore maritime transport emissions.”

Well, that's a step in the right direction so something to be applauded. But taken alone, an emissions reduction of "almost 1.5%" isn't going to save the planet.

How does this work? The article assumes I should already know the mechanics of it, but googling only seems to turn up a bunch of the same sorts of articles.

I'm not an expert on it really. They rotate the giant cylinder and the wind is blowing by. The rotation forms a low pressure zone one side of the cylinder which acts as a lift force perpendicular both to the rotational axis of the cylinder and the wind.

It's the same effect which "turns" a soccer ball if you kick it with a spin. There is a really nice demonstration of the effect in this video: https://www.youtube.com/watch?v=2OSrvzNW9FE

This wikipedia page has a way better summary than my attempt above: https://en.wikipedia.org/wiki/Rotor_ship

I assume you’re referring to the Coanda effect.

I think rotor sails leverage the Magnus effect, not the Coandă effect.