Interesting....
https://www.horizontechnology.biz/blog/electric-motor-design-radial-vs.-axial-transverse-fluxAvator motor is a big lump by the look of it, and heavy too.
With battery 27kg, same weight as a Honda 5/6 HP...but I guess you can split the Avator in two parts?
Plate is known as an anti-ventilation plate. This explanation is relevant.
"The anti-ventilation plate (AVP) does not stop or help prevent cavitation. Its sole
purpose is to prevent surface air from being sucked into the negative pressure
side of the propeller blades. This plate creates a high-pressure barrier that
prevents exhaust gases and ambient air from being sucked back into the blades.
Anti-ventilation plates are mounted to the lower units of boats and can also help
increase performance somewhat. They act as a small planing surface to get your
boat on top faster. They give you better bow response when trimming your
motor. They keep water down at your prop and intake, improving water pressure.
All planing boats and vessels equipped with stern propulsion, outboards, stern-
drives etc., are equipped with anti-ventilation plates, however there are no
established theoretical models for the function, why most of them are based on
legacy, production limitations and trials.
The future propulsion powered by electricity will open-up for radically new and
more efficient designs. Decoupling the mechanical driveshaft will provide
positioning and function freedom.
Even if electric propulsion will remove the exhaust, the surface air is still there,
however, the design and function could potentially be different."
https://www.chalmers.se/SiteCollectionDocuments/Industri-%20och%20materialvetenskap/Kandidatarbeten%202020-21/IMSX15-21-14.pdf