Windmill boat bettery charging

[That old Mercury]

Hi
I will probably get kicked off this forum for this question!
But here it goes!
I was looking at solar to charge my batteries because i dont have power at the site i keep my boat.
I am disabled and i just cant keep carrying batteries back and forth charging them at home.
What if i mount a power generating windmill on my boat ?
It will be turning making power while boat is moving.
Then with a selector switch i would select the isolated battery to charge
Then on a return back to ramp switch battery to charged one and charge the other.
I already have a selctor switch to use battery A or B .
I know i cant charge the one that the boat motor is charging at the same time.
Also is thier a law saying you cant pull a boat down the highway with a windmill on it turning?
I see some windmills rated to 50 m/s that is 110 mph , i am only driving 65 mph.
Windmill would be 500 watts , 29 amps.
No law of physics will be broken this way , No overunity either.
I will Appreciate all the laughter and comments !
Thanks

 

[alldodge]

Is it legal to tow a windmill, don't know, but guessing it's if it posed a hazard or distraction to others

They make different types of windmills so it might work