I can only comment on what YOU point me to which is a tiny motor and control
Vs the motor
That eMKay shows that is big enough to have chance of putting out the power necessary to move the boat
"Our Sailboat Kit will convert your 3-12 HP diesel engine to clean, silent electric!
We've supplied these systems for sailboats up to 30 ft. long, and 12,000lb displacement, that are achieving hull speed. All systems have reverse on-the-fly and contactor disable.
Brushless means no brushes to wear out, and no ignition source for on-board gas appliances."
I always like it when they cant show you a single working install
The gas or diesel motor that was there had a powerband that had to followed to allow the boat to move efficiently and the electric motor has a powerband that will also have to followed to allow the motor to work efficiently
Then your not even thinking about the air flow necessary to keep the electric motor and control from having a meltdown when its closed up inside a boat a drawing 100 + amps
And most of what we do at work is change out OLD school mechanical Variable Speed Drives to Modern Electronic Variable Speed Drives and if you don't do your homework on the it does not work out well.