The "Electric Wheel"

[ssullivan]

Ok,

We had a great discussion about the WhisperGen in another thread. I have been looking at another alternative boat product called the "Electric Wheel." It's currently an option in Lagoon Catamarans, and I saw one at a boat show with the engine.

The technology here makes 100% sense to me. Advantages are:

*Fuel Efficiency
*Quiet Operation
*Little to no routine maintenance
*Can use solar, prop spin, etc... to add to energy used to propel boat
*Single power source - because so much electrical energy is used to power this system, you can easily siphon off power to run any number of DC electric house items (fridge, etc....)

Negatives seem to be:

*Cost ($37K to power a 40' heavy displacement world cruiser)
*Battery life - how long does the AGM bank last?


I really like the convenience of using a single source of power that can be supplimented by renewable engergy. Here is a link to the website.

Any opinions on this one?

http://www.solomontechnologies.com/S...dvantages.html

[Rick]

Nigel Calder wrote an excellent article in Professional Boatbuilder mag. discussing the "way to go" if one is currently putting together a boat. The "way to go" is to use a brushless dc motor to drive the prop shaft and a diesel engine driving a dc generator. The speed control for the diesel becomes almost trivial in that it only has to monitor the dc output voltage and control the rpms of the diesel to keep the voltage somewhere near constant. An additional dc to ac inverter would give you ac power without the requirement of having a fixed rpm generator.

The Solomon solution is probably one of the most expensive, yet high tech and good. Because the cost of fuel is not going to go down it will pay to use a system like this which can essentially double the fuel economy over that of a conventional diesel directly driving a fixed prop.

Sure, a battery bank would give you some ability to immediately have prop power yet is not essential to the design. For cruising reliability the diesel is essential.

For those of you who think "green" it is important to realize that hydrogen fuel cells and photovoltaic panels using today's technology will NEVER pay off over the life of the system in that the input cost of the use of fossel fuel required in the manufacture of these technologies exceeds what fuel one would use by using an efficient diesel engine/generator like what one can install using a brushless dc drive motor and diesel generator to provide energy. At first you might think that this is blasphemy yet it has been analyzed many times.

Rick

[Strygaldwir]

I think it is apparent that we have to start investigating new methods of meeting our fuel requirements. Currently, yes, fossil fuels are more cost affective. But, as our reservse go away and we start calculating the cost of maintaining our supplies ( what are we up to in Iraq?) the balances start to shift, dramatically.

I have spoken with the founder of Solomon it is good technology. What's needed is more affective/efficient storage and generation facilities. It is a 144v dc system, so I suppose you could mount 6 24 volt panels and provide an unlimited amount of "free" power.

The generator alternative is a little noisey. But when the boat is running under batteries it is pure heaven!!! Completely silent. High torque. I LOVED it.

Keith

I did buy some stock, so I may be partially biased.

[Alan Wheeler]

Hmmmm, OK firstly I am not bagging this idea. It has merits. But there are a lot of figures that just don't add up and a lot of figures needed for comparison, that are ommited.
OK so firstly, lets presume we have no losses in the system. She is 100% efficient just for this excersise. So we have a 12Hp motor which = 9KW. At 144Volts, the motor will be drawing 62.5A. That means for the 6x 24V solar panels, they will have to provide approx 250W each. That is mighty big panel. Ofcourse there are losses, lots of it with Solar. So looking at a generator, to run this, well there are losses there as well. Everytime you convert some for of energy to another form of energy, you have a loss. So the Genset losses energy and the motor losses energy and the wiring and the speed controlling and so on. A diesel engine fitted direct to a propellor is actually more efficient, a gearbox slightly less. But the part about propellors and torgue at low speeds and so on, is actually full of a few errors. Plus, it is interesting that all the boats listed are what I would consider as being on the very low end of horspower to wieght/length ratio for Diesel, let alone the Electric.
The hydrogen fuel cell has potential. But it is still too expensive and I don't know what ongoing costs will be if any.
Anyway, just my thoughts.