As the Powerball goes up so does my browsing of the Nordhavn website - I'm
not an owner but plan to be at retirement.  I've always been intrigued by
the diesel electric Siemens system, and I noticed that the page describing
it is no longer there.  On a search of the site it still show up, but it's
not listed where I thought it was (under Construction Fundamentals).  While
it doesn't seem the technology is quite ready for prime time (only one boat
I know of using it and some third hand stories of Nordhavn talking people
out of it as an option - again, only hearsay) but I've always felt it was
great idea (redundancy, house power, etc.).  Anyone have any first hand
experience with the technology, or have an idea why it appears to be pushed
aside?

Thanks,

Chris Rietmann

(hopefully retiring with an N55)

Chris said: "...Anyone have any first-hand experience with the technology
[diesel electric], or have an idea why it appears to be pushed
aside?..."

I am a Nordhavn 68 owner, who requested diesel electric for my boat.
Nordhavn rejected my request. They had just launched the 55 and the 64 and
were swamped with orders. I had talked them into doing the 68, which they
were already struggling to fit into the production line. They didn't have
the bandwidth for the added complexity associated with a diesel electric
boat.

Since that time, I have toured the 76 which is diesel electric, and taken a
short ride. I was extremely impressed, and strongly believe there is a
future for diesel electric.

The basic concept is simple. Instead of using diesel engines to propel the
boat, you have a series of generators providing electricity to electric
motors which turn the shaft.

The implementation is a little more complex. The electric motors are
different than my expectation. Whereas I expected something recognizable,
these were water cooled and I think there were four motors a shaft (or, was
it two?).

I was also surprised by the size of the generators. Whereas I was expecting
to see a row of 25kw or 50kw generators, I was suddenly looking at a 100kw
generator (this is from memory...) and several smaller generators. I looked
like a conventional large main engine, not something in a neat little box.
My vision that the engine room would be empty was shattered, because there
were also a lot of wires, and a very large industrial-looking electric
panel.

I'm not sure what horsepower it takes to propel a 76 at 10 knots. My guess
would be around 200 horsepower. If this is close, then I compute this as
somewhere around a 150kw requirement. That's a bunch of generator output.

Actually, the electric motors looked easy to swap should one die, and there
appeared to be plenty of redundancy. And, generators are generators.

So, do I wish I had gone diesel electric? The part that most worried me is
that we are planning a circumnavigation. My fear was that a "normal
mechanic" such as I might find on an obscure Pacific island, might be
somewhat intimidated looking at all the complexity. I knew I sure as heck
was. There's a lot to be said for having well-known systems on a boat.

I have heard positive reports about the fuel range (I'm guessing a 5%-10%
improvement over conventional systems), and I participated along with the
diesel electric 76 on a run from San Diego to La Paz Mexico recently, and it
performed flawlessly.

I do not know what Nordhavn's current thinking is on diesel electric.

-Ken Williams
Sans Souci
www.nordhavn68.com