We're definitely going electric motor with a battery bank. The boat is currently rigged to run things like the A/C only when connected to shore power, but I'm going to try to get it all running off the battery bank with a gas generator supplement.
Propulsion
Pretty much everyone else on the reservoir has a Ray Electric motor (
http://www.rayeo.com/motors.htm), which run $5K+ just for the motor and another $2K for the battery bank. Quite honestly, I think Ray Electric has grown complacent, and their prices are too high and their motors are outdated (I think they're still selling the exact same motor as they were in the 70's). A small start-up company in Germany has recently released a new line of high-power electric motors that appear to stomp the Ray Electric motors (see
http://www.torqeedo.com/us/hn/products/cruise-r.html). I'm buying the Torqeedo cruise 4R motor (48V, 4HP), which should be plenty big for this boat. It will definitely be the first motor besides a Ray or trolling motor on the water, but then this is the first houseboat on the water as well!
Power
While I toy around with the idea of using 12V marine deep cycle batteries, pretty much everyone is telling me to go with the 6V golf cart batteries instead. At this point I'm planning to buy 16 Exide GC2-H 6V batteries (often refered to as E-145's) (see
http://www.exide.com/products/golf_car/spec_golf_car.html for specs). As mentioned above, 8 batteries would power the motor (48V), while the other 8 would operate as a "house bank" for the rest of the boat. This number of batteries would allow me to put 4 in each of the four corners of the boat and have an even ride. Our lake is only ~900 acres, which sounds big but really isn't. You can pretty easily get from one end to the other in 15 minutes. In other words, I'd say an average day may involve an hour of moving and 8 hours of drifting. The grill I'm mounting on the front uses propane and the stove inside uses alcohol. The sink and water tanks are powered by gravity, so there's little else to suck the juice beyond the radio, small TV and boat electronics. Here's the stock layout of the boat:
For anyone interested in more details, I've purchased a Xantrex Freedom 458 charger/inverter for the house bank. It has a 110V AC output of 3kW (up to 9kW/75A surge), and can charge the battery bank at up to 140A DC. The air conditioner (penguin 13.5K BTU) uses up to 15A of 110V AC power. That's pretty much the only thing I plan to connect via AC power, though, so it is well within the range of the Xantrex inverter. The refrigerators and everything else should use 12V DC power from the house bank. I also plan to run the Honda EU1000iA generator (1kW or 8.3A of 110V AC) to the Xantrex charger/inverter when attempting to run the A/C, motor, refrigerator, etc. at the same time.
I still need to run the calcs on battery capacity, inverter load and so forth. Again, I have no real idea what I'm doing, so feel free to critique away!!