Ron asked, "What is your plan for charging underway. I assume we are talking a large battery bank." I plan on ~1000 AH battery bank using AGM batteries at 24 volts. To charge underway, I'll have two 200 amp 24 volt alternators driven by hydraulic motors. Since I'm using variable displacement hydraulic pumps on the main and auxiliary the alternator speed will be independent of engine speed and either engine can drive them both, which provides 400 amps for a total of 9.6 KW. This arrangement also eliminates drive belt wear and replaces belt maintenance with hydraulics maintenance. The auxiliary engines speed will be controlled by a hydraulic pressure demand throttle control, which assures that it runs just fast enough to meet the power load of the hydraulic loads, as opposed to an AC generator which must maintain constant speed regardless of load. This arrangement is more fuel efficient, improves engine life and produce less noise than an AC generator. Another advantage is I can produce full electrical from the main engine while underway without running the generator or auxiliary. To combine the output of the two alternators and assure that they both provide current to the battery bank, I'll use a Balmar "CenterFielder" <http://www.balmar.net/page21-centerfielder.html> http://www.balmar.net/page21-centerfielder.html . As a backup for total hydraulics failure, the alternators will be mounted one on each engine with belt drives but the belts removed. By disconnecting or bypassing the hydraulic motor and installing the belts, I'll have 50% of normal capacity from either engine or 100% if I run both (although I'll only get 50% when the engine is running at moderate to high speed). I was worried about drive belt side loads on the water pump, but I saw a solution to that at the Helicopter conference last week. They mount an idler on the opposite side of the engine from the water pump and an extra set of belts going to the idler. A spreader bar pushes the alternator and idler apart to provide belt tension. This arrangement assures that the belt and idler belt tension matches and since they are in opposite directions the side loads cancel. Regards; Mike Schooley Designing "Portager" a transportable Passagemaker