[Paal Gulli]

Jacques Cousteau (probably the greatest enviro-weenie charlatan of all time) built one in 1985. Claimed it was 3.5x-4x as efficient as a Marconi/Bermuda-rigged sail.

If its so efficient, 40 years later, why hasn't it taken over the world?

https://web.archive.org/web/20220401032800/https://www.cousteau.org/legacy/technology/turbosail/

[TexasGator]

Those are turbosails. Similar but different.