I personally don't see the advantage with the current selection of electric hybrid systems. We had one Manta owner who insisted on installing a system in his boat, I felt so strongly about the lack of advantage I told him we would build the boat but he would have to contract direct with the system manufacturer if he wanted it. Based on the comparison to the usual twin 30 hp diesel with 5kw 120v diesel generator, the hybrid system cost twice as much, was 300 lbs heavier, was a knot and a half slower under power. The fixed three blade props that were supposed to provide "regeneration" when under sail created so much drag, the boat was a couple of knots slower under sail and couldn't tack in light air because of the huge turbulence over the rudders. With the maximum battery capacity at 144 volt dc the boat could motor for about an hour before the 14kw generator was required so you end up with a diesel running 95% of the time anyway so much for being "green". With all the complicated electrical relays, inverters, batteries, one good lightning hit, and you better know how to sail. With no stand alone generator or redundancy of twin engines, if this generator failed, you lost everything. I think the systems that do not run through a battery bank and go direct probably make more sense but in the end what are you really accomplishing? Diesel technology is getting better and more fuel efficient all the time, 120v generators are getting smaller and quieter. Military submarines have used the technology for a long time, but mostly for silent running not to be more efficient. If you read the articles recently written in professional boatbuilder after real data comparison in conclusion they had a hard time justifying any advantage. Right now as far as I am concerned, for the manufacturers that are pursuing these systems it's more about the marketing "gee whiz" appeal or supposed environmental angle. I think a classic reply offered when I asked my father who is a marine electrical engineer and diesel mechanic by trade what he thought of the idea, was "WHY "?