What Energy Systems Are Best for the Pacific ?

[impi]

I am finalising our Cat for next years departure on our world cruise, and have had some comments on the dock create 'Brain scatter'.

We have a genset, Gel battery bank, balmar alternators rigged thru centerfielder, are building a frame for Solar Energy and two stands for wind generators. Our course takes us from Cape Town viz South America, Bahamas, San Blas, Panama Canal, Galapogos and to French Polynesia. We intend spending a few years around French Polynesia etc etc.

Today I had a shock when a cruiser told me I would have problems in the (South) Pacific withn both Solar Panels and wind generators.

The reason is that apparently the Sun rises ahead of the vessel and with Parasailor etc. the solar panels lie in shade. The wind seldom gets over 11-12 knts so wind generators dont work. Anchoring behind Islands means no wind - so wind generators dont work.

Am I wasting my time looking at Solar and Wind Generators - in which case I should not build the frame ???

Please could anyone with experience of these cruising grounds assist me

[simonmd]

Not sure I understand what you mean when you say the sun will rise in the wrong position. Correct me if i'm wrong, but the sun ALWAYS rises in the same place, ie, EAST! The fact you're in the S Pacific would have no bearing on this.

Also, as the day moves on, the sun will, of course, move from one side to the other so the panels will certainly get some direct sunlight at one point or another. Most decent panels can produce a resonable amount when the sky is completely overcast anyway, so a bit of shade in the morning isn't going to hurt them too much. For then to remain in shade, you'd literaly have to be sailing in a big circle to follow the sun.

As for wind, the Anchoring could be an issue but to say that the general wind will seldom get over 12kts is a bit weird. Don't forget that when going upwind, the motion of the boat will add to the actual figure and if its still less than 12kts (aparent wind) then im surprised that anyone could sail there.

[witzgall]

Unless you are sailing that spinnaker while at anchor, I think you are going to be just fine. While the scenario your friend painted might present itself, ask yourself how many hours, of the TOTAL hours you will be there, could this be a problem. Most cruisers spend the majority of their time at anchor, not sailing a spinnaker downwind.

Chris

[impi]

Thanks Guys,
I get your point .... and yes it all seemed a bit odd to me, but he was pretty convincing having had spent time there. So would you still feel the wind generators are a good pitch for charging while at anchor, or would you stick with solar alone?

[daddle]

I'm in the Equatorial Pacific. 100% of power comes from solar (250W). Sometimes it rains for a few days in a row which forces me to run the engine a bit. No wind power for me. I don''t think there's enough regular wind in the nice anchorages or while sailing my slippery boat downwind, but some people say it helps.

It's all about conserving power and getting the panels out in the sun. It takes a tiny bit of work. Like said above, one spends most of their time at anchor so make sure you can move the panels out from under things that will shade them.

It's the fridge that eats the power. Spend some time making the insulation perfect and thick.

[Paul Elliott]

Even with the sails shading the solar panels, you will still get a useful amount of power. Not as much as unshaded, but not insignificant.

Sailing downwind your wind generator will probably be a poor performer, but there should still be some apparent wind (unless things are really light). In the south pacific anchorages that I've visited, the wind generators are often spinning at a good clip.

I think you've got it covered. You should put together a solid energy budget, so you won't be too surprised. I assume that my solar panels average about half their theoretical daily output (due to shading, etc) and that seems about right. Make sure your battery capacity is sufficient for your planned use.

[zeehag]

i like the combo of wind and solar as sun doesnt shine in storms but wind blows then-- so , if you donot wanna use the genny, go both,we did in gulf and loved the capabilities we gained.
i WISH i had a wind genny installed on this boat now! i am in sin diego--sun isnt at good position for max charging and we ALWAYS have wind from 1100-1900 daily.
also--underway--wind works well - so does solar. nav lites use a LOT of energy. if not led--3 amp0s PER HOUR for EACH regular 12v bulb you have running ALL night long. yes--you want wind and solar. that way you still have enough juice for whatever you wish to do in morning. solar dont charge at night--

[donradcliffe]

As much of the South Pacific is downwind sailing, the wind generators will probably not do much while at sea, but will contribute quite a bit while at anchor. especially in the atolls. Solar is also good, and you should consider a water generator. We used a Ferris, and usually ended the passages with full batteries and no engine/genset use.

[Bruce Bevan]

I think you have all been `had'. Telling someone that the sun us in the wrong direction to generate power when in the southern hemisphere is a akin to asking you to go and get a bucket of steam or a left-handed monkey wrench.

[delmarrey]

I'll second the water generator. They work any direction you sail. When at anchor, power is less important so then solar would be my choice.

IMHO wind gens are good for land but on boats are a useless pain. In the S. Pac. the wind either blows like hell or just a little bit.


.

[Bruce Bevan]

Delmarry's point is valid. I did some work in the eighties on an experimental Darius Turbine (120' high) located on Christopher Point near Victoria, BC. The advantage of the Darius (eggbeater style) blades are that they are at their optimal orientation to the wind no matter how gusty or variable the wind is. We are all familiar with the variability of the wind and on a conventional rotor style turbine the turbine has to turn quickly to orient the blade perpendicular to the wind flow otherwise the turbine efficiency drops rapidly. Christopher Point is located along a rugged mountainous shore that you could classify as a very gusty site. Wind turbines must be located where winds are steady and turbulent free. The big downfall of this turbine is that it needed 10 mph wind to start but it had to shut down when the wind reached 30 mph or it would fly apart. I think this applies to most any wind turbine. This is a small operational window considering the PNW has virtually no wind in the summer and either near hurricane force storms or calms in the winter. The result of this experiment was the turbine generated about $550.00 on average per month. Not worth the mega thousands it cost to install and operate it, but the design held together till it was dismantled thirty years later. It was just installed at a poor site.

Please call the turbines wind turbines and not wind generators. After all, they are not generating wind.

BB

[Jon Hacking]

Originally Posted by impi

...So would you still feel the wind generators are a good pitch for charging while at anchor, or would you stick with solar alone?

A lot of folks do both, but unless you have a HUGE amount of space, the wind turbine will usually shade the photovoltaic (PV) panels at some time. I see a lot of wind turbines placed above & close to PV arrays, & it doesn't take much shadow to shut down a PV panel.

Personally, we had both on our trimaran in the 80s, but didn't like the noise of the turbine. This time we're going pure PV (480w nominal) mounted above the davits & that works great at anchor or even on day sails. See our Solar Panel page for more. The hotter the sun, the colder the beer!

But the PV doesn't quite keep up with the autopilot (4A, or 100A-Hr/day) when we're on passage (with the sails shading the PV panels half the day). Historically we're only on passage 7% of the time, so only 25 days a year. I don't mind running an engine a bit on those days, but I'd probably grab a towing generator if one crossed my vision. We had one on our tri & it worked pretty well. Just make sure you have a big funnel to slide down the line to facilitate retrieving the prop.

[Minggat]

Originally Posted by impi

.... and yes it all seemed a bit odd to me, but he was pretty convincing ...?

I've been convinced of a lot of things that caused the voice inside my head to say ... "huh"... and ask questions like you are here.

From Bruce Bevan
"I think you have all been `had'. Telling someone that the sun us in the wrong direction to generate power when in the southern hemisphere is a akin to asking you to go and get a bucket of steam or a left-handed monkey wrench."

Yep. Some people make no sense while depicting themselves in a convincing manner as a reliable source of information, said the guy who has been guilty of it once or twice.

[noelex 77]

For many boats their solar generation is better (less shadows) when the sun is from behind.
Some parts of the world have a very constant wind direction at least during certain seasons.
If this wind direction puts the sun from in front when at anchor solar output is likely to less, sometimes much less is the mast shadow is constantly on the panels.
In the northern hemisphere areas with north winds will be better at anchor and in the southern hemisphere south winds will give you more power.

I disagree with your friend and think you will find your power output will be good in the South pacific, but the hemisphere combined with the prevailing winds are a factor to consider.

[BlueWaterSail]

On Steady Beat, the wind gen is up on top of the mizzen and dedicated to charging the starter battery, while the solar panels take care of the house (switchable to starter if required), and are hinged on the pushpit so that they can be angled through 90+ degrees to follow the prevailing position of the sun from horizontal to vertical. Flexibility is the key.

BWS