[Public-list] RE: ELECTRIC DRIVE

[Meinhold, Michael J]

Silence is also very good for certain large ships that don't want to be
heard.
Some other benefits of electric drive :

1) separation of power source from drive source. This could work for a large
sailing vessel to keep weight low and amidships. On big ships it allows
podded
propulsion without complex power trains.

2) Modularity of power sources. This only works in large ships where you
might want to sometimes have several power sources and mix and match them
between propulsion and auxilliary service

3) Tuning of the propeller to the driver, not the power source. Electric
motor technology is improving to the point that RPM and torque can almost be
chosen independently.

In any case, what I was originally addressing was not electric drive, but
the use of the propeller as a power source, and that as Gordon said, it is
not adequate. 

Mike
Rinn Duin #272

-----Original Message-----
From: public-list-bounces at alberg30.org
[mailto:public-list-bounces at alberg30.org]On Behalf Of George Dinwiddie
Sent: Tuesday, September 14, 2004 12:50 PM
To: Alberg 30 Public List -- open to all
Subject: Re: [Public-list] RE: ELECTRIC DRIVE


Yes, the advantage of electric is not performance, but silence.  I knew
a naval architect on the CompuServe Sailing Forum who was considering
building a hybrid launch with a small gas motor in a well-insulated,
well-isolated box generating the electricity.  The concept was a bit
bulky for a typical sailboat, though.

 - George

On Tue, Sep 14, 2004 at 12:20:19PM -0400, Gordon Laco wrote:
> That actually sounds pretty good!
> 
> Gordon #426
> 
> 
> 
> 
> 
> 
> 
> 
> > The manufacturer sent me an estimate based on the size, shape and weight
of an
> > A30.  He recommends an an OZtwin motor, a battery pack (8 pcs of Leoch
fiber
> > battery, 110 Ah each) that will provide 4 knots cruising speed with
about 8
> > hours range. Full speed will be approximately 6½ knots and the range
will be
> > about 1 hour.  Recharging is while underway (at a slow rate) or more
rapidly
> > while plugged into shore power at the dock.  The performance is not
great, but
> > it is the cost that really puts this option out of the box.  The cost of
the
> > total system is about $7,000.00 US.  John Manza
> > _______________________________________________
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