Of course you're right -- I had the "30 foot sailboat" blinders on
when I wrote the post -- Parallax started the thread discussing a
3,600 pound keel.

To put this in perspective, though, 1,000 pounds of lead acid
batteries will store less than 8 kilowatt hours -- call it 10
horsepower hours -- on a regular basis with reasonable battery life.
This will take our 30 foot sailboat about 5 miles.

There are a wide variety of battery technologies under development,
primarily for automotive applications, that will probably help this
along in the next five or ten years, But don't look for too much --
we might see the weight difference fall to 20 to 1 from 200, but I
don't expect to see parity in my lifetime.

Jim Woodward
www.mvFintry.com

"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message ...
"Jim Woodward" wrote in message
m...
A pound of diesel stores the same energy (on a practical basis -- not
the 20 hour rating capacity) as 200 pounds of lead acid battery.
That's why there aren't more electric boats and cars.

There are lots of electric boats. But they are a bit specialized. It wouldn't surprise
me if there were more electric trolling boats than cruising sailboats!

Also, there are a growing number of electric auxiliaries installed on club trainers and
other small boats. And companies are now offer small diesel electric setups - handy for
catamarans to drive two motors from one genset.

One of these days there will be a major breakthrough that makes battery power much more
feasible. If only Moore's Law applied to battery technology!

-jeff