[aerohead]

* I'm not seeing any connection to dolphins.
* It's 'reciprocal' motion, rather than 'rotary.'
* It appears to 'borrow' heavily from Dyson's 'bladeless fan.'
* The supporting strut is hydrodynamically 'dirty.'
* The toroid itself is hydrodynamically 'dirty'.
* A back-to-back comparison to an equivalent energy consuming 'Minnkota'-esque electric trolling motor would be instructive.
There's no context in their 'comparison' which would suggest any advantage as far as thrust-per-kWh ratio.
* Third-party testing / benchmarking.