On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote:

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are going to
be some complex boxes and equipment in between the generators and the props.
Keeping them cool and dry will be a challange. The wiring will be unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion plant.
There will be some effeciency losses so you will need to carry more fuel on
a boat that already is devoting extra space and weight to this enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it in a
60 foot sailboat. If having a DE sailboat is a goal in itself because you
like to tinker and want to be a pioneer, cool. If you just want to sail and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.


There was an article in "PassageMaker" a while back about the
conversion of a trawler yacht from diesel to diesel-electric. It,
frankly, looked like a corporate promotion article -- perfectly
lighted photos and from the prospectives , obviously professional
camera equipment, but anyway.

The crux of the article was that the owner removed two main engines
and replaced them with a single, larger prime mover driving either an
alternator or generator (I don't remember which way he got his
electricity). Each of the original propellers/shafts, etc, were
replaced by DC motors directly coupled to the shafts. The whole
caboodle was SCR controlled and the genrator/alternator and both DC
drive motors were water cooled. The electric controls looked similar
to the SCR controls in an off shore drilling rig.

From looking at the pictures there appeared to be little of the
installation that was "off the shelf" and my guess was that the whole
installation must have been far in excess of what the original twin
engine installation was.






Bruce in Bangkok
(brucepaigeATgmailDOTcom)