Our experience has been similar to the above comment. In our first boat with minimal electrical demands (no freezer, water maker or washing machine) a good battery bank and solar panels and our big alternator on the main engine worked fine. I never used a wind generator for 2 reasons: first they make a lot of noise and second we have been in anchorages on 3 occasions where they shed their blades and in doing so caused significant (but so far not lethal) injury requiring hospitalization twice and major damages to another boat nearby. Few mention the safety hazards associated with wind generators but a 3 foot plastic blade rotating at high speed in a 25 kt wind will go a long way and hit very hard and nearly always where no medical help is available.
However, once we moved aboard our second boat full time things changed. Our electrical demand is much higher and an even larger battery bank and alternator for the main engine is ok while under power but there simply was not enough room for an effective array of solar panels. A diesel genset harnessed to 2 big battery chargers putting out 25% total battery capacity works great. We usually run the gen set either once a day for 1 .5 hour, or every other day for 2 hour. The output is sufficient so we can power a 26 gal/hr water maker and the clothes washer and charge the batteries at the same time. I may be wrong here but in my own opinion I think many of the problems with diesel gen sets result from them not being used frequently and I believe this is why som many small boats with diesel gen sets fail. Diesel engines and water makers both benefit from frequent if not near daily use. Our 25 kw gen set burns 0.6 gal/hr and once a year preventive maintenance results in a lot of energy.
s/v Waterwitch

I also have had great results from an Aquair towed generator on long pasages. It gives me about 6 amps at 7 knots. The only problems are securing it on the rail and the difficulty of recovering it without almost stopping the boat.

Water towing generators attract big fish ? Has anyone ever had a fish attack one ? It would have to be one hell-of-a big fish ! I towed one trans-atlantic west to east with only great success. Pulled it in when we started the engine and got a tangle of the line, which when disconnected from the generator and dumped back into the water in the reverse order it was brought in ( hanging onto the propeller ) it would promptly sort itself out. A great bit of kit, kept us on batteries powering radar, lights, SSB, etc. no problem. I love the thing.
Bill R.
SV Blueprint
Nicholson 31-113

Hi Daria,

We have Trina solar panels, an Outback charge controller and an Eclectic Energy D400 wind generator.

Our solar is mounted slightly lower than I would like on the davits and so they are partially shaded until 8am or so in winter but they perform admirably. I recall that our best day ever was 2.7kW of solar input - the wind clocked from W through N to E! Nice to see the batteries on float!

Thanks for that. Sounds really good. Would you mind sharing the brands of wind generator and solar panels you installed?

Vice Commodore, OCC 

We have 400Ah of batteries and a 100Ah charger attached to our generator. With a fridge and freezer we had to run the generator for at least 2 hrs per day on passage to keep things reasonable even although we had a wind generator.

The wind generator would supply about 2/3 of our daily needs when we had more than 20kt of steady wind. Below that (most of the time) its contribution was modest.

2 years ago we installed 440 Watts of solar panels with a dedicated MPPT charger - lifechanging and so liberating! I had to rewire the hot water heater through the inverter so that we could have 'free ' hot water rather than wasting the energy as most days our bank was full by 1pm. (S Bahamas/Cuba area). We can now leave our appliances on and not worry too much.

As important to us is that we now only run our generator for a few hours a week when we need to make water although that will change shortly as I 'm about to install a dive compressor.

Our experience found solar to be quite good in most areas when used to top up the batteries and sized to carry the daytime sailing load plus add 30amp hrs. That is to say when used with a diesel generator. Our batteries lasted 9 years they were marine grade gell batteries grp 27. So they were nothing special and only a few were bad but we went to replace them all. On days of little sun we just did not get the batteries toped up as well but then we get some sun and it would top them up nicely. We didn 't see much success with wind or water generators and only solar was usually under-powered. Diesel generators worked great but you need away to add the last bit into the batteries.
best
greg
S/V ErinBrie

Many thanks for your note David. I imagine we 'd have difficulty with any transom array as we have a Monitor windvane self steering system mounted there. Please do keep us informed of your learnings this winter.

Vice Commodore, OCC 

I agree with your assessment of technologies.

My view is that you should fit as much domestic battery capacity as you possibly can and a simple, proven, diesel generator with the out put to charge them as fast as they will take it (that means a charging current about 25% of rated capacity I.e. A 400 AHr bank can be charged at 100Amps - you will need a smart charger to manage the batteries).

My boat is large, so that I 'd need a big solar array to make any material contribution but wind generation is still an option. however I can get most of the power back into the batteries in the time I need to make water so that I get good efficiency out of the generator.

There is a fixed towed generator made by Witt & Sea (german) (a much smaller version of the Duogen (and without the vane!) that I will look at this winter. It is transom mounted, is said to make a big contribution with little drag. But then I will have to learn to live with less water!

Thanks Rob. Fuel cells sound almost too good to be true. Will definitely investigate.

Vice Commodore, OCC