On Thu, 02 Jun 2005 10:13:43 -0400, rhys wrote:

On Thu, 02 Jun 2005 12:43:35 GMT, (Mic) wrote:

Perpetuated Motion
Electric propulsion for boats: A century-old technology may just be
the wave of the future

LINK:

http://www.cruisingworld.com/article...ID=396&catID=0

" Advocates for diesel-electric propulsion list among its virtues that
it's clean, quiet, efficient, and requires very little maintenance.
Another advantage frequently noted in connection with the STI system
is the ability to make electricity--to "regenerate"--when the boat is
under sail."

"While internal-combustion engines are typically described by their
horsepower rating, STI's motors are named for the torque they develop.
An ST 37 puts out 37 foot-pounds of torque or 6 horsepower; Tether
recommends using it on monohulls up to 32 feet and 10 tons or to
replace diesel engines of up to 24 horsepower. An ST 74 puts out 74
foot-pounds of torque or 12 horsepower; Tether recommends using it on
monohulls up to 50 feet and 16 tons or to replace diesel engines of up
to 48 horsepower."

The ST37 is right in the range for my current light cruiser, and the
ganged ST74 is appropriate for my anticipated next boat, which would
be a modified full-keeler.

I'm watching this technology like a hawk. It makes a lot of sense on a
number of levels, but of course, it isn't for everyone.

In the meantime, I'm replacing the exhaust end of my old Atomic 4....

R.
The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.


Weebles Wobble
(but they don't fall down)

On Thu, 02 Jun 2005 13:27:27 -0400,
wrote:


The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.

I can see that with a multihull. My current boat wouldn't enjoy 12
batteries, all that copper and the required charger, either, But
certainly there are passagemakers and full keelers that could have the
batteries low and in return shrink the size of the diesel tanks to
whatever would reasonably cope with the genset's occasional use.

I also anticipate a lot of competition in this area, which I hope will
spur further savings in weight and complexity.

R.

On Mon, 06 Jun 2005 13:41:50 -0400, rhys wrote:

On Thu, 02 Jun 2005 13:27:27 -0400,
wrote:


The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.

I can see that with a multihull. My current boat wouldn't enjoy 12
batteries, all that copper and the required charger, either, But
certainly there are passagemakers and full keelers that could have the
batteries low and in return shrink the size of the diesel tanks to
whatever would reasonably cope with the genset's occasional use.

I also anticipate a lot of competition in this area, which I hope will
spur further savings in weight and complexity.

R.
I agree. I think STI is a good first offering that will be built on by
others in the near future. I am not sure what the benefits are of
using the 144 volt motor vs a 24 or 48 volt system. I use an electric
truck at work that does quite well on a 48 volt system and have
wondered if someone will follow up and offer a system that can use a
more practical sized battery system.


Weebles Wobble
(but they don't fall down)