The coolest recent development in marine propellers is toroidal propellers which are now commercially available and seem to perform significantly better than standard propellers: https://www.sharrowmarine.com/
LoganDark 1 hours ago [-]
That website seems to no useful information; only marketing speak about how great it is... Do you know of a good source on how toroidal propellers work and the engineering behind them?
This reads a lot like an advertisement.
The linked page [[Cyclorotor]] is more neutral and has more information on the design and applications outside of marine vessels:
https://en.wikipedia.org/wiki/Cyclorotor