I have no experience with electric drives but I see a lot of advantages to them combined with a generator and a decent size battery bank. I doubt it will be lighter, probably more weight with the drive, batteries, and generator...but certainly not more than a engine & generator.
I have been starting to research electric drives for our application, our engine has almost 4,000 hours on it and there is not a good fit replacement IMO, Yanmar would be the closest to the W50 we have now.
Some advantages I see with the little research I have done:
- Unlimited control of the prop speed between stop and WOT
- No shaft alignment to deal with
- No stuffing box/shaft seal
- No "transmission" to maintain
- AC power to run things such as heat/ac/hot water, etc...with an engine designed to do so
- Reduced noise and vibration, often you can find a generator complete enclosed in a sound dampening box and they can be very quiet with the right mufflers...unlike our engine which is not in an "engine room" but open to storage areas under the cockpit (hard to explain on a T37)
- Oh yea, and I suppose you could put the generator just about anywhere it would fit, although on our boat I would thing where the current engine is would be best...and I could put it on a slide out to work on it...no more contorting my body into inhuman shapes! LOL
Just few that I have been thinking are good one? Dunno for sure, but to me it makes a LOT of sense.
PS. I would also consider solar and wind generators to supplement and use the diesel only when absolutely needed.