Even though it's same all over again, I don't mind to repeat my point of view, and actually my point of view slightly changes as more information and options taken in consideration.
First argument - "it can't run for long period of time so you still must start engines/generator". Let see. Everyone says sailing/motoring is just 5% of time, 95% -
anchoring or short trips between islands/ports etc.
And then, out of these 5%, how much time in real life sailor spends motoring? I bet not much. Because middle size cat will consume at least 2 gallons of diesel per hour of motoring, bigger - double of that. That's 48 gallons per 24 hours plus associated noise! That's $150 per day! Will get very expensive very quickly. So unless one won the lottery, he will try to not start engines often. Plus - electricity (generator) still needed for
water maker, AC (if any), dehumidifier(s), dive
compressor,
propane needed for
cooking,
engine started for all these short trips between the islands (as you know almost all the wear engine gets at startups, until
oil pressure is developed) etc, etc.
Now my point of view of good hybrid system and it's behavior.
I think it should be parallel setup. Yes, boat will be heavier this way and it probably makes sense only on bigger cats (say, 45' plus, when extra weight not as critical).
Powerful
solar setup - must have. Big Li-Po
battery bank - must have.
Wind generator - I'd say must have. Currently I'm developing system, allowing to mount 7-15 kW of
solar array on almost any bigger (45' plus) cat. What it will give you? Unlimited power for everything on the boat even on rainy day, even with partially shaded
panels which you can not completely avoid on sailboat (and I'm talking
well equipped boat - with AC, electric
stove, big fridge and all other comfort things). And even then, there will be some power for electric propulsion (but most likely still enough for that 95% of time when no long run needed and considered that you've been anchored previous days, your
battery bank is full). So virtually, 95% of time boat not using fossil
fuel at all. Out of remaining 5%, most likely 4.9% you will be sailing, right? Remaining 0.1% AND
emergency situations - that's where you will need your diesel engines (but I'd still rather have this kind of "backup").
Second argument - it's too complicated, it will break, blablabla. Let me guess - you guys, probably afraid to drive modern cars while on hard, because afraid of "very complicated injector engines, data bus control and other modern crap? While it's actually true regarding the car, solar/hybrid system on boat not THAT complicated. Anyone with good
electrical knowledge can fix/modify it. But of course, it will scare these who can't
repair electric
winch or stopped working AC.
Third argument - it's expensive. Well, this is actually correct one. All of described above only makes sense when newer expensive cat purchased, and hybrid conversion, along with solar/wind setup and battery bank will be part of initial investment. But from my point of view - all solar/wind/battery upgrades would be absolutely required anyway, along with
repairs and other
refit, so cost of installing hybrid drive at that point won't make huge difference. Why would I need such powerful solar setup, 4-6 kW
wind generators and huge battery bank? So I can enjoy unlimited AC, unlimited fresh
water, unlimited
cooking, dehumidifiers to keep things dry and free of rust, unlimited use of dive
compressor etc. All of this without starting engine/genset. It's just different point of view, opposite to minimalistic - having minimum comfort, minimum weight (for fastest speed, I guess? But sailing is just 5% of time, remember?) And yes, I know how to fix that stuff when it will break (or if I don't, I will learn, it's that simple).