The Offshore Voyaging Reference Site

Self-Sufficiency In Power

When we were planning our new boat, one of the first aspects we discussed was our preferences for power generation, and our desire to have as much “free” energy input as possible. There were three reasons for this: our desire to avoid the complexity of a diesel generator; our own commitment to renewable power after so many years of both working in the environmental field; and a chance to agree on something—it’s always a good idea to establish some common ground first!

Top of the list was a wind generator. Having owned one of these devices on a previous boat, my views on them are straightforward. None of them are the quietest things to live with, so if you must have one, then its output must justify the discomfort factor. So we opted for a Superwind, and having lived aboard for the last few weeks it is a revelation. Not only is it quiet (enough not to annoy the neighbours), but with a maximum 350 watt output when there is enough breeze, is well worth having. Being German, it is nicely engineered and built, and looks like it should be a real asset in the long term.

We also wanted plenty of solar, so we have two long slim panels with a combined output of 90 watts on the OVNI arch at our stern. Following good advice we had these mounted so that they can articulate. Two more semi flexible panels with a combined output of 96 watts are about to go on the coachroof ahead of the mainsheet where they will not be subjected to too much foot traffic, and hopefully will not suffer too much from shading by the boom. Finally, we have a very nice 80 watt solid panel which can be articulated on the guardwires for maximum output when in port or at anchor. All of the panels were carefully selected for reliability and sustained output, as opposed to peak, so we feel that we should be able to make a solid contribution to our daily needs in this way.

The aim has been to achieve a balance between wind and solar. In the higher latitudes we tend to frequent, wind will generally have the upper hand, but solar can still contribute due to the long hours of daylight, and, very occasionally, when the sun shines. The best we can hope for is that each technology works at its best for some of the time.

Our engine is fitted with a high output alternator, rated at 105 amps, and we are going to see how we get along with this unit without any “smart” type regulator for this season. With a battery capacity in excess of 600 amp hours we may have to consider fitting a second alternator in any case, so once we have tried it out over an extended spell living aboard, we’ll know more. We really want to avoid running our engine at anchor, which is not only unpleasant to live with, but is death to a diesel engine in any case. If all else fails, we have a neat little Honda petrol generator that we’ll use.

We are planning on buying a towed generator for longer passages, as these units are reckoned to offer the most amps per buck, normally around 1 amp output per knot of boatspeed. Being simple, robust units, we have high hopes of running the engine as little as possible on passage, as long as fish don’t go for the spinners too often.

Finally, we have tried as far as possible to audit our requirements, and reduce our daily power consumption. We are slowly going through the boat checking what lights in the interior can be fitted with LEDs and which not. We have a masthead combined tricolour and anchor LED unit to conserve energy when sailing or overnight, but have not bothered with our running lights, as we’ll be under power then, so little will be saved. And we have no freezer unit, simply an efficient coolbox, so that’s another significant drain we don’t have to worry about.

We are aware that none of this has come cheap. If we added it all up it, including installation, would amount to perhaps two thirds of the cost (and installation) of a genset. But we think that if you have a genset, then the next thing will be that you will have more need of it—your power requirements will increase in line. Then there are the spares, and so forth—and don’t even mention reliability. And we accept that we may have to live more frugally than some others out there, but feel it is all relative, and that living simply is a tiny price to pay for the huge privilege of going long-distance cruising.

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George Woodward

I am just fitting an Ovni arch to my Ovni 32 (Sandy Creeden at Falmouth who has done work for you, is doing this for me).

I am going to fit solar panels and wonder where you sourced your long slim panels and articulating mounts. If you had a photo from the other side that would be very helpful.

Dimensions are critical because I am fitting an Ovni 345 arch which raises some compromises. While the 320 beam is not much less (3.31 – 3.60) it is not carried so far aft. This means unless the wing is to oversail the side of the hull, finding a position that gives enough width to the wing for solar panels, enough headroom to step down below it, a position for the side struts on the coamings to give the typical rearward leaning angle of the struts. And at the end it needs to look OK!

Thanks for any information you can give me.



Philip Merlier

Good day:

We are the owners of a Cape Dory 36 (Evergreen). We sail primarily the coast of Maine and the Canadian Maritimes (Nova Scotia & Newfoundland).

We wish to gain more independence from running our engine in order to generate power. We have already reduced our energy requirements, and we are now looking at alternate ways to generate power.

This winter we plan to add a Superwind 350 and two solar panels to our Cape Dory 36. They will be mounted on an arch off the aft deck. Each solar panel will be mounted in a fore/aft orientation on each side of the back stay. We were hoping that each panel would be of the 125 – 130 output size (each about 26 inches X 59 inches).

Question: From your experience, should we be concerned that the larger size of these panels may adversely affect the sailboat in strong winds? Do you think that that there will be any noticeable effect? We noticed that you have smaller panels on your boat which is larger than ours. We could always downsize the panels that we hope to install if your experience indicates that we should be concerned?

We want to get this right the first time and value any input that you may have.

Thanks and best wishes.

John Harries

Hi Philip,

Just a note to add to Colin’s answer. You can see a larger photo of his excellent and strong installation in this post as well as a lot of photographs of how not to do it!



Your proposals sound fine to me, but here are a few thoughts which might prove helpful.

Our panels are long and slim, which maximises the area but makes them less ‘bulky’. Maybe look at different panel shapes to find a suitable alternative.

It’s really important that you can make them adjustable – this, plus a little effort on your part will make a huge difference to the daily output. Ours orientate fore and aft through around 45 degrees either way.

You’ll be fitting a regulator, so it makes sense to go with the new MPPT technology, which is worth at least 10% extra per day. And keep the panels clean – when you’re reliant on small outputs every little bit helps.

The Superwind is a great unit – ours is now over three years old and has performed flawlessly. And with the new blades it’s really quiet – see my post on this site.

A combination of wind and solar is definitely the way to go where you sail.

Best of luck with the installation.


frank gilroy

i have taken over the repairs and parts sales for four winds generators and due to the fact that i can not buy new gen motors from the original suppliers, i have been forced to find ways to repair non functioning units.

not only can i fix these units but i can do it at a fraction of replacement costs .

i should be able to apply this technology to all types of wind generators and charging systems .

we also have full machine shop services and fabrication capabilities . we can make custom parts to your order and design.

you can reach me at pipebender101@gmail .com or call me
we are located in east Tennessee but can ship any where i cruised the Caribbean and west coast Mexico for several years and know how important power generation is.


frank gilroy
201 978 3267