New Tecnologies?

[sandy daugherty]

Lets talk about the carbon footprint of a regenerating system like Dave Tether's (ex Solomon Technologies) electric wheel. IIRC, The Conser 47 with ST motors shown at the Annapolis Show in 2003(?) could be set for a 6 kt 'cruise' so that when a gust increased boat speed the motors would generate electricity instead of using it, for a net gain for the day. How does that fit the footprint accounting approach?

[Amgine]

All of the electric wheel motors are set up to do this. The idea is to set the motor at a speed just slightly less than the average through-the-water speed, which will use a small amount of electricity but reduce drag (three-blade fixed prop) to near zero. And, of course, as you get a gust or slide down a wave you generate electricity (with an equally momentary increase in drag from the prop.)

As far as the carbon footprint, this is a great method. I do not know what the embedded energy cost of an electric motor of this type might be, but I would guess it would be comparable with that of a diesel motor or perhaps slightly higher (more complexity, but softer metals if it's copper windings.) However, in electrical generation mode it has to be considered that the total carbon footprint of the boat, rig, and sails have to be added in - they are part of the generation equation. This is in contrast with either the solar panels or the diesel, each of which produce energy without requiring the boat.

But without the boat, what's the point of the electricity?

The idea of combining the electrical generation with the motive power is why a diesel is so convenient. This actually makes me consider the idea of switching to an electrical drive.

But not until my current power plant packs it in.

[jphillips48]

What about using a gulf cart motor as an aux. power source? How well will they work? Have you tried it?

[sandy daugherty]

Golf Cart Motors are very old technology and are used for their ease of service and reliability and not for their efficiency. I think I read that they are too inefficient for even home made water turbine generators where there is ample continuous flow. But there has to be a lot of them laying around. Soft metals, cheap castings, stamped steel plates and the fact that you might be using one that has been rewound are all positives.