The Survival Podcast Forum

Energy Options => Wind Power => Topic started by: mangyhyena on January 05, 2014, 11:41:18 AM

Title: Sailboat wind power turbine?
Post by: mangyhyena on January 05, 2014, 11:41:18 AM
I'm just throwing an idea out to see what you all think.  I put it in the wind power section, but the generation and storage aspect could be applied to just about any system designed to harness our ocean's energy far from land.  Ships could be sent to collect the energy and bring it back to shore.

To charge a small battery bank on a sailboat, I was wondering about the feasibility of dropping a turbine in the water.  I was thinking that as the wind pushes the boat, the turbine in the water should turn as it is pulled/dragged through the water, charging the battery bank.

It would slow down the sailboat when operating and I don't know how large it would need to be for the purpose of battery charging or how expensive it would be.

If it would work on a small scale, I wonder it could be scaled up to an industrial level.  A large ship with sails and a turbine or turbines beneath the stern.  Ship moves forward, turbine turns, electricity is generated.  The electricity could be stored either in batteries, perhaps Nickle/Iron for long service life, or converted to hydrogen and stored.  I figure that if the input energy is wind, rather than fossil fuel, the 3 to one ratio for electrolyzing water wouldn't be so bad for the environment or the input cost.  Hydrogen storage aboard ship would be harnessing and storing 1/3 of the total energy during a trip.

Anyway, ships like this would leave one port empty and arrive at another port full of energy ready to be offloaded.  Two ships, one at port A and the other at port B, going back and forth between ports, would bring in energy each time they arrived to each port.  Lots of them would bring in lots of energy.

Using modern weather forecasting and perhaps tethered "kites" to catch the wind currents at elevation might help make the system more efficient or reliable.
Anyway, it seems like a way to harness some of the natural energy in our oceans, which cover 70% of our planet and is currently unused for our energy needs.

I realize that the materials used to build the equipment leave a carbon footprint, but to be fair, so do the materials used to build new power plants.  At least the ships don't require the burning of fossil fuel to operate.

What say you all?  Another crazy idea that won't work?
Title: Re: Sailboat wind power turbine?
Post by: never_retreat on January 05, 2014, 12:34:43 PM
I don't think we could build anything big enough to meet our energy demands.
I think tidal would be easier to harness.
Title: Re: Sailboat wind power turbine?
Post by: mangyhyena on January 05, 2014, 02:15:33 PM
Build a large enough fleet?  You might be right about not being able to build supertanker-sized sailing ships unless it's for transporting oil.  Don't know.  During WWII, we quickly built a large fleet of war ships, but that doesn't mean we are capable of doing that again with energy harvesting ships.  I don't think anyone would argue that we , today, are the greatest generation, or anywhere near the greatest.

For tidal energy, I've been wondering if dams could be used, letting high tide in through turbines and low tide out through turbines.  Perhaps stock the dam with fish meant for food, like a fish farm.  Might be nice to go to the beach and know no sharks are swimming by you.  Then again, maybe it would be bad for sea life.  Don't know.

What I do know is there is a lot of kinetic movement in our oceans and we're not using very much of it.  There is plenty of room for equipment out there and if we could store even 1/3 of what is available, it would go a long way towards meeting human energy needs.

But, the moment we decide we can't harness ocean energy, wether or not it is viable becomes a moot point.  Hopefully, Exxon will help end our reliance on oil and coal.  :)
Title: Re: Sailboat wind power turbine?
Post by: Skunkeye on January 05, 2014, 04:12:23 PM
This system wouldn't really be harnessing ocean energy (the energy from wave and tidal action).  It's just harvesting wind energy, and pretty inefficiently at that.  You're using a lot of your captured energy to move the ship and overcome the drag of the water on the hull and the turbine.  It would be more efficient to just put wind turbines offshore, anchored to the sea bed like oil rigs, to take advantage of the higher winds out where there are no landforms or buildings to block them.

DIsregarding that, batteries would be a non-starter for such an application.  Lead-acid batteries have about 1/250th as much energy per pound as crude oil or natural gas.  Even the best lithium-ion batteries on the market are only five times better, so even if you could get past the enormous cost, you'd need 50 supertanker-sized ships to bring in the equivalent of one ship of hydrocarbons.  Hydrogen, if compressed highly enough, would have the energy density to make it practical, but the efficiency losses would be enormous.  Sailing a ship around, dragging a turbine behind it, to crack water molecules and compress the resulting hydrogen - that's a lot of lost energy.  I don't see how that could ever be cost-competitive even with solar, much less traditional wind turbines.

Capturing tidal energy through turbines is already being done, on a fairly large scale:

One idea that I've seen proposed that seems really cool is to attach tidal generators to bridge pilings.  The bridges are already there, so there's not much anyone can say about aesthetics or environmental impact, and it would be a simple matter to run cables up and along the bridge to bring the power to the grid.
Title: Re: Sailboat wind power turbine?
Post by: gopack84 on January 07, 2014, 03:05:28 PM
If you've got some hours to kill, this is a really interesting course. It's called "Physics for Future Presidents" and he goes into a lot of detail about energy. The problem is that gasoline is just so really, REALLY good at what it does which is store a lot of energy in a small volume and mass. There's really not much else that is consumer friendly that can compete on cost and most everything else has additional problems hydrogen (delivery and stability), batteries (cost and capacity and conversion losses), nuclear (well... lots of problems to make yourself a nuclear powered car), solar (efficiency of photovoltaics and just the total available energy per sq meter from sunlight), and so on.

Definitely worth a listen if you're brainstorming alternative energy I think. The course is designed to be a high-level course with a minimal amount of math needed to prove things to yourself. The downside is it is probably nearly 30 hours of material, but you can pick and choose because the internet is great. (
Title: Re: Sailboat wind power turbine?
Post by: Hurricane on January 07, 2014, 03:33:24 PM
Don't some boats already use wind turbines to charge the on-board batteries, especially on long-distance cruises?
Title: Re: Sailboat wind power turbine?
Post by: riptide on January 07, 2014, 04:35:34 PM

To charge a small battery bank on a sailboat, I was wondering about the feasibility of dropping a turbine in the water.  I was thinking that as the wind pushes the boat, the turbine in the water should turn as it is pulled/dragged through the water, charging the battery bank.

Use to do this sort of thing for dead reckoning, known as streaming a log.
The turbine would spin a line that would tell your approximate speed and distance traveled. That thing was forever getting fouled on seaweed. Only time I ever got seasick was on a dark night with complete overcast and no visible horizon.... and then I had to go clear the log and stream it again! You should be able to do it the old way, but GPS wins every time for accurate navigation.

A fixed location is just going to work better for either tide energy or wind energy collection.
Title: Re: Sailboat wind power turbine?
Post by: mangyhyena on April 11, 2014, 11:39:26 PM
Someone thought the idea of a hydro turbine on a sailboat had merit.  They obviously had the idea long before I did, since they manufacture and sell it.  Just found their product. (

Guess no one explained to them why it was a bad idea.  Worse still, there are fools out there actually using this product, not realizing how inefficient and just unmanageable this foolish idea is.  Poor saps even seem happy with the performance.  Their customers blather on about generating all the energy they need for their sailboats with this inefficient product.  Why hasn't anyone told them that even though it meets their needs, it's a horrible idea and we've decided it's inefficient?

You all are absolutely correct.  There are solar panels, windmills, and hydro turbines meant for streams and rivers and dams only.  Any other alternative to coal and oil is just a pipe dream that can't possibly work.  I think we should just stick with oil and coal.  If there were a viable, abundant, clean alternative to coal and oil, like, say, harnessing energy from the oceans that cover 70% of our planet, science would have identified it by now and our government would have made sure to implement it.
Title: Re: Sailboat wind power turbine?
Post by: Skunkeye on April 16, 2014, 12:10:43 AM
Jeez, guy, don't take it so personally.  I don't think any of us in this forum are really in favor of just continuing to burn fossil fuels until we run out.

But you do understand there's a big difference (in complexity, efficiency, and economics) between a tinkertoy that generates 500 watts of power to charge up a couple deep-cycle batteries on a recreational sailboat, and a floating power plant that would need to harvest many megawatt-hours of electricity to be economically viable, right?  The kinds of solutions that work on small, personal-scale systems (where efficiency isn't quite so important) don't necessarily scale to industrial sizes.  Just like the solutions for fossil-fuel power generation are different for a household generator vs. a steam-turbine power plant.  Both might run on natural gas, but you're not going to generate 50 megawatts to power a city with a gigantic internal-combustion engine, and a teeny-tiny 10 kilowatt steam turbine would be inefficent and overly complex as a single-home backup generator.  You can run a digital clock off a potato and a couple nails, but you can't run a profitable power plant that way, no matter how many potatoes you stack up.  "Horses for courses", as the British say.

Could you build the kind of ship you're talking about?  Probably so.  Would it be cost-competitive with other wind-harvesting technologies already out there?  I don't think it would even be close.

I agree with you, the ocean is a vast, untapped source of energy.  Tidal generators like the ones I linked to earlier are proof that the technology exists to harvest power from the seas.  Other ideas, like floating wave-capture devices (like the Pelamis ( machine) are still in the prototype stage, but have great potential.