[PUP] Nordhavn removes diesel-electric page from Construction Fundamentals section?

[Ken Williams]

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