http://www.duffyboats.com/page.cfm?pgid=1 is a great place to start. Duffy builds a first class vessel and their website sings the praises of electric boats.
That said, Duffy's are expensive, SLOW, heavy, SLOW, have classic lines and don't go very fast either.
Utilizing a electric trolling motor works if you use it on a canoe or kayak. Use one on anything else and by the time you get all the batteries you need onboard you'll find a expensive, SLOW, likely ugly inefficient watercraft.
I too live in FL, right on the ICW and travel it extensively. The past month found me throughout FL and GA on the water and I saw 0 electric boats. There is a reason for that. I have seen a lot of very inexpensive and free boats and there is a reason for that too, the most common is that fixing them would cost more then they are worth. There is always the urban legend of the wealthy widow wanting to get rid of hubby's toy but usually wealthy widows didn't get that way giving expensive toys away.
On a practical, non teasing level, six miles an hour, the speed a sailboat under power travels, takes patience, perseverance and the willingness to learn how tides work. If you have a maximum speed of six miles an hour and your heading into a three knot current then your speed over ground (SOG) is three miles an hour. To travel at that speed you need a lot of patience, a lot of batteries and no schedule or inclement weather. Experienced sailors on the ICW time their travels to go with the tide whenever possible. This means they spend a lot of time at the dock or on the hook (at anchor) waiting for favorable tides.
There are very efficient larger vessels using electric power. These vessels use electric turbines powered by diesel engines. Large diesel engines.
Still, google electric boats and see what comes up besides WWII submarines. It will be a fun learning experience.
But, any boat, fresh or salt water, gas, diesel, oars or electric, requires maintenance, insurance, registration plus skill and knowledge in boat handling, safety and first aid. We figure our boat eats about 30K a year in maintenance & fuel and fuel is going up and maintenance ain't never gone down.
Good luck, keep up with the search and maybe you will be able to teach Don Quixote something. I know my wife would love an electric boat, she would truly love not listening to the engines or smelling the fuel or buying the fuel either but bless her heart she isn't ready for an open boat or one that can't fight the tides. Plus, she has to have her own head on board and if you gotta pee you can't use hers.
Boating is fun, maybe not as much as you think but it's fun. It's not surrounded by 25 y/o hard bodies in bikinis the way the ads show, more older folks and more older boats with the occasional mega yacht (saw a few yesterday).
Mike
