I use this 86 lb thrust motor, with two LiFePo4 batteries. I wouldn't venture into even protected ocean waters with it, but I may be too cautious. It moves the SCAMP at about 5 knots or so with both batteries connected, in Lake Lanier, an inland lake with lots of motor-boating chop.
Winds whenever I use it are minimal, maybe 2 knots. I have not tried to use it against or across a wind more than that. It's just for saving time when the wind dies near sunset.
This setup will run for at least 2 hours on the 2 batteries (I think it would go quite a bit longer, but I've never run the batteries completely dry to find out. I've run both of them at once (always at once) about 2 hours and more than half the charge is supposedly still in them, based on the charger's LED readout.
It's mounted on a standard little outboard mount.
https://www.amazon.com/gp/product/B004XAGXE0
Motor
https://www.amazon.com/gp/product/B00KJE9POE/?th=1
Batteries: 2 of these:
https://www.amazon.com/gp/product/B09H7J9CW7
This waterproof circuit breaker is 100% necessary, in my opinion. Makes life much easier: you can turn the motor on and off, not even touching the handle of the motor.
https://www.amazon.com/gp/product/B09S3TC6YG/
David
With a big wind over a long stretch, though, the hull speed will be the limit... not the parasitic drag. Then it's just free electrons!