Solar-Powered Engines ?

[Dsanduril]

Having multiple battery banks allows one set to charge with on system, while drawing from another.

Sorry, but that is the least efficient method of battery use. At their very best the battery charge/discharge cycle is 90% efficient. More generally the round trip is 80-85% efficient. For every 100 units of charge you put into a battery you get back only about 85 units. Far more efficient to utilize the energy directly if you can. Batteries should only be used when you can collect the energy now, but want to use it later. If you are collecting and using the energy at the same time then it should not be making a trip through the batteries.

For the OP's question - check out Educational Tall Ship. They are proposing an electric auxiliary system that will scavenge charging power from the rotating prop while under sail. It will slow the boat down under sail, but will charge the batteries for maneuvering with the motors later. Not sailing yet, so we'll see how realistic it gets to be.