Alternative/Supplemental Power Sources

"Has anybody ever tried setting up ..."

To extend that concept a bit further, the power created by the passing water could be used to power a fan that blows on a sail and the boat would go even faster!

The fan on the boat filling the sails doesn't seem like a very efficent idea to me. Sure it would fill the sails but the fan would always be dragged along with the boat.

I do however believe thast this idea of a boat mounted fan has been tried before with some success it's called an Air Boat and the fan blows air out the back not against a sail.

I'm leaning toward Motorsailers. We always seem to revisit the past in Yachting, so there you go. Then, this green thing/global warming would suggest as much as well. Then, too, there's the old commonsense aspect which is in short supply these days: motoryachts go slow in reality and sailboats are always powering someplace...plus, a Seaton/Neville 63/70 design (I will bet Lars has some hot-stuff designs as well) has gobs more interior space than, say, a comparable Nordy...in fact, I'm thinkin' more volume-for-the-buck may be the way of the future, IMHO.

"I just got to thinking about all that water passing the hull and wondered as I'd never heard of it."

Please tell us that was a joke question ...

OK ,the fan blowing on the sail must have been too subtle.

Let's put a propeller on the bow to drive a generator and convert the energy in the "moving water" to electricity and have that power a motor that drives a propeller at the back end to move the boat and make it appear to the captain that the water is moving ...

I guess the whole thing was too subtle.

OK, let's try this. We burn diesel fuel in an engine to turn a reduction gear to turn a propeller shaft to turn a propeller that creates thrust and moves the boat through the water. The captain sees water "moving" past the boat and a light bulb illuminates, not literally but one of those little cartoon bulbs over his head.

So, we now stick a propeller or a paddlewheel or something in the "moving water" alongside so the "moving water" can turn a shaft and drive a generator that makes electricity to light a real light bulb. Is this more illluminating or is the misconception still a bit too dim?

Hi,

NYCAP- I am pretty sure I have seen a few cruising sailboats with an alternator that is driven by a towed prop. These are used to charge batteries which I assume also provide lights.

I have not seen this on any motoryachts. Anything you tow that takes power to turn it will be costing you fuel, there is no such thing as free power, even the sailboats pay a bit in speed loss but as their fuel is free when sailing they are the best placed to take advantage of this type of thing.

There is no reason why you couldn't use a wind generator on a motoryacht I am not sure of the overall savings thugh when you consider the cost of the equipment and the fuel to haul it around whether used or not. It would give you some battery charging at anchor without running ya genset or main engine to provide the same.

There are well known ways of harvesting the waste heat from engines and exhausts but these are generally for heating feed water etc and are not widely if at all used to provide electricity. Most of these are in use on ships that are underway for days on end so the operation of these can stabilise.

Here is some reading to cure your insomnia http://www.greenspower.co.uk/ieconomisers.shtml

The posts in this thread have been split from the "2015" thread and moved to a new thread, titled: "Alternative/Supplemental Power Sources", which is a good subject. If we keep it constructive, maybe someone will shed some light.

"Anything you tow that takes power to turn it will be costing you fuel,..."

I probably should have just wrote that to begin with instead of trying to lead him make the connection on his own.

Maybe there are other captains who don't understand that the boat is moving, not the water. If there is a power "recovery" device intended to extract energy from the passage of the vessel through the water, it is impossible for it to produce net energy. It will always cause drag and increase energy consumption far beyond what it returns. Energy is lost at every conversion, otherwise perpetual motion would be a fact of life.

Wind turbines create drag until the speed of the wind exceeds the relative wind created by the vessel's passage. Does the amount of time that net power is available exceed the cost of fuel to haul the weight and drag of the wind turbine around? Probably not, unless the thing is mounted on a little sailboat where alternative power sources are heavy, expensive, noisy, and smelly.

Dragging a generator around behind a sailboat is a trade-off. The power extracted slows the boat but the wind power to drive the boat is free. Slowing the boat is usually considered a fair trade for the noise and cost of running a diesel generator. The amount of power is very low but so is the power consumption of the little boats that use that system and those things normally just charge the house battery, not supply consumers directly.

The bottom line is there is no free lunch in the energy business. There are ways to utilize the waste heat from diesels. You can use it to run evaporators, generate steam for heating or to drive a generator. But given the cost of these applications and the operating pattern of most yachts, the equipment would probably rot before it paid for its own carriage. The only practical use for heat recovery I can see as worthwhile on a yacht is the evaporator.

I see the next decade of development ripe pickings for those who sell "hydrogen boosters" and energy recovery devices to the technically challenged. Real advances will be made and efficiency improved but it will be incremental, expensive, and for the most part difficult to justify for reasons other than a legitimate environmental concern or to meet increasingly stringent regulations.

Hi,

Here is a bot more reading:

http://www.duogen.co.uk/whydual.htm

and try scrolling through this one, there is no registration here just scrool down from the opening page

http://www.cruiserlog.com/forums/index.php?showtopic=3895