Solar Engines on a Boat

E

El and Bill

New member
We have had many discussions of the uses of solar power on our C-Dorys, ranging from solar showers to solar vents and solar charging for batteries while boats are in storage.

Out of curiosity, I googled solar engines for boats and found many interesting sites. Solar-powered boats have crossed oceans, circled Earth, and driven speed boats at high speeds.

I'm not suggesting one would want a solar engine on a C-Dory today -- but it is interesting to see the experimentation going on with solar engines for boats. The economics, I'm sure, would be daunting -- but fun to think about cruising along in silence on a C-Dory -- much like the pleasures of listening to wildlife cruising on our sailboat, under sail and light winds, in Florida with the grandkids.

Has anyone seen or cruised on a boat powered by solar engines? Or has anyone evaluated the economics or drawbacks/benefits?

Just trying more ideas for discussions on long winter evenings where it's still a bit chilly for boating.
 
Its expensive, in comparison to sail. Its slow on long passages, which have taken the trade wind routes because of the increased power to go against wind and seas/current. For example the Solar 21 cost $575,000 to build, and made 140 miles a day--down wind, and down current, in 26 days. Our sailboat cost about $130,000, and made about the trip in 15 days and averaged about 175 miles a day, There was little fuel used on the sailboat--less than a gallon a day to run the diesel generator--no main engine. The sailboat had much more room, and submit was more seaworthy.

I am aware of 3 transatlantic solar boat transits.

I am only aware of one solar circumnavigation--that was a 100 foot 16 million (plus) dollar boat--taking 19 months. I have several friends who have circumnavigated in about the same length of time--and the boats cost in about less than a new C Dory....

The other issue, with solar power, is the actual carbon foot print to build the cells, batteries and boat--far more than to build a sailboat...

Then look at sailboats which attempt to use solar to run the systems--again expensive. I have a friend with a 45 foot Cat, who tried to run refer/freezer, electronics etc on solar only--his cost to set it all up was about $40,000, and then found out he had to have a generator or run the main to generate power. It takes a lot of solar panels to really run heavy duty appliaces on a full on cruising sailboat. You can get by with less--but smaller refer, minimal electronics etc...
 
There is a solar pontoon boat built. Some folks have put solar panels on Duffy and ElCo boats. Golf Cart batteries run about $70 each--on up to about $140. Many of the Electric boats use the larger L 16 Traction batteries--which are more expensive--and far heavier. But these boats are only for putting around the harbor type.
 
Off topic, but:

I was wondering about the possibility of running a boat like a plug in hybrid, especially for cruising. You've got a multipurpose generator that can charge house and cruising batteries, and an electric drive prop connected to the cruising bank. The generator starts/stops based on the cruising bank voltage. I'm not imagining this sort of setup working for planing speeds, but I'm curious if a CD22 could run at displacement speed with a setup like this.

The Chevrolet Volt's gas engine is only connected to a generator that charges batteries or powers the electric drive motors. The gas motor is never directly hooked up to the wheels. This seems like it could translate to a boat motor system.
 
This has been done for some time--in various forms. Nigel Calder became involved in Hymar (http://www.hymar.org in about 2008. He had discussed the technology before that time. If you go to his blog, you can see his impressions of the project. Not perfect--and some limits.

In essence of course we have been doing this for a long time with Diesel Electric subs and trains...

In 1985 we crossed the Atlantic with a sailboat which had thousands of lbs of some exotic batteries--and an electric motor, solar panels, prop generator and a small diesel to run the electric motor in reverse to charge the battery bank. The owner did not design the system, but picked up the boat cheap, because of some issues, with weight, and performance.

Bob
 
I was aware of the hybrid drive for trains and subs. It's fun to see the diesels come up in the locomotives when they really start pulling. I was just curious if it had been attempted on a small scale, like our boats, and if it could be feasible for low speed cruising.

Imagine in a few years taking out your gas tanks on the 22 and putting a bank of batteries in their place with a semi-permanent generator in between. Then the electric outboard bolts onto the transom and tilts up and down. Could be a pretty similar system and form factor. And the marinas could have high amp charging slips to allow the boats to act more like plug in hybrids.
 
The batteries are very heavy--at this time--or too expensive (like lithium) plus then you have to carry fuel for that generator.

There are drop in packages currently available at:
http://www.propulsionmarine.com/
The 5.5 KW package with Solar Diesel Electric is about $18,000.
This would give you slightly over 7 HP and a speed of about 5 knots.

If you want a bit more you can go to the 10 KW diesel electric--NO solar, and that will give you about 13 HP, and maybe 7 knots...But the boat will be considerably heavier than the one with an onboard...

So it commercially avaiable--and has been for some time--but just not practical currently.

The 5.5 KW with a sail boat in and out of the slilp--OK-but your Toqueedo is cheaper and will do close to the same thing.
 
Correction:

The Chevy Volt's "range extending" gas engine does directly drive the front wheels at speeds above 70mph and when the battery is depleted.

It is really just an advanced plug-in Hybrid and not what was initially promised. Even the current info on the car misleads the reader to believe it is all electric.

Still waiting for the original design because I could get behind that small gas generator feeding batteries only concept.
 
In my opinion, the future of boating could be fuel-cell-powered, high-horsepower, electric outboards -- not solar or battery based technologies. There was talk of an ultra-high-capacity, variable-rate-discharge capacitor being developed, but thus far, it has not come into fruition.

Rich
 
As a off - topic to Ferret's off topic re. the gas engine not being mechanically connected to the prop. I met a gentleman a few years ago who had designed and built his own hydraulic drive. He had bought a outboard boat with a blown powerhead. He removed the power head, leaving just the lower leg, then built some sort of case on top of it that used hydraulic pressure to turn the driveshaft. He used a 18hp gas engine to drive the hydraulic pump. Forward/reverse was controlled by the use of valves. Speed was controlled by engine/hydraulic speed.

I never saw the boat but he showed me lots of pictures and it looked impressive. He was a retired machinist. He said his low speed control was the best.

Regards, Rob
 
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