Two into one has been around for years. Back in WW2, some landing craft
used 4, 6-71's connected to a single shaft through a clutch arrangement.
I'd bet the problem will be to find someone doing this on a regular
basis for a boat the size you want ... i.e., anything can be engineered,
but the cost and benefits may not compare.
Turbo electric, diesel electric, steam electric is also common on larger
applications ..... BG Mayhaps some of the "hybrid" technology for cars
will soon find it's way to more boats.

Y,
Modern cruise ships use the Azipods. They've had them for quite a few
years as I remember.
Paul


Y wrote:

I actually read it was first used on ships in combination with steam
engines, so yes, that ain't too new BUT technology has advanced quite a bit
in the mean time. It might just be time to look at the technology again now
with new materials, power semiconductors and better electric
motors available. I think it looks pretty exciting. Of course you'd
want to get a picture of the cost. As far as availability, I found this:

http://www.abb.com/global/abbzh/abbzh251.nsf/wfrmMainFrame!ReadForm&db=/global/seitp/seitp161.nsf&v=17E96&e=us&ep=&c=F061D79CE14FC002C1 256BFA0051BB3A

If the link is broken, just search for 'azipod' on the abb home page.
I think ABB at least is thinking there is future in it.

On Wednesday 19 January 2005 21:42, Paul Schilter wrote:

Y,
Modern cruise ships use the Azipods. They've had them for quite a few
years as I remember.
Paul




They say they have compact versions starting at 500kW, which would be great.
But I guess I got a little overexcited about the possibilities today, I read
that just about now the first superyachts are being equipped with
this kind of propulsion. That probably says it all looking at price.

Frankly I don't really get the 'podding' idea. Why not simply replace
the diesel engine with an electrial motor, add the required electronics/
control systems and be done?
Why should they opt for an (imho) very ugly POD bungling down there,
doing nothing good for drag? I also think they might be too easy to destroy.
Yes I suppose you get amazing manoeuvrability in return but not everyone
is interested in that.
Could be that by podding the engine they have a more expensive package to
sell. Or perhaps there actually is some pressing technical reason.

On Wednesday 19 January 2005 18:29, Capt John wrote:

Hi, I do remember seeing a marine transmission that tied two engines
into one output shaft. It was in a trade paper, I'll have to see if I
still have it at home. It was a commercial unit that only allowed one
engine to be in gear at a time. I'll look for it tonight.


Sounds very interesting. If you can find it please let me know
if they have any dealers. And if it is suited for small engines
(say 400kW)!

On Tuesday 18 January 2005 21:19, BigBadJohn wrote:


Y wrote:
Hi all. I am looking for a long-range trawler and notice that many
converted fishing boats and other interesting (for me) ships have
just one
engine.

The problem would be to balance the two engines. Which is why you
typically see either 1 shaft per engine or one generator per engine and
a electric motor driving the screw.


Did you actually see that second option somewhere?

BigBadJohn wrote:


Y wrote:
Hi all. I am looking for a long-range trawler and notice that many
converted fishing boats and other interesting (for me) ships have
just one
engine.

The problem would be to balance the two engines. Which is why you
typically see either 1 shaft per engine or one generator per engine and
a electric motor driving the screw.

Y drives are available, some large motor yachts use them.
They allow you to run on 1 engine for economy cruise and both
when you want to go faster and burn plenty of fuel.

The added advantage is a shorter engine room because the engines
are mounted at 90 degrees to the centreline.


--
My real address is crn (at) netunix (dot) com
WARNING all messages containing attachments or html will be silently
deleted. Send only plain text.

Read an article on a single engine with two props, outperformed a single by
quite a margin.

Sterling

BigBadJohn wrote:
Y wrote:

Hi all. I am looking for a long-range trawler and notice that many
converted fishing boats and other interesting (for me) ships have

just one

engine.


The problem would be to balance the two engines. Which is why you
typically see either 1 shaft per engine or one generator per engine and
a electric motor driving the screw.



I looked at a 30's Packard that did this, It was a mechanical monster.
Both engines were coupled together to a single drive line. The power
plant was called a "Twin Six" is my memory is right. A guy was selling
it and told me it took him about 10-15 minutes to get the engines in
proper sync after they were shutoff. This was needed to make sure the
strain on the "box" (Can't recall when he called it") where the two
engines were coupled to a single drive line would break.

The trick here was not to just get them idling at the same rpm. But when
one would tap the gas pedal the rpm's had to "bounce" the same. It had
adjustable choke gas and magneto slide adjusters to help one get it in sync.

This was a car that was designed to be driven by a professional

Capt Jack R..

On Thursday 20 January 2005 15:59, Steven Shelikoff wrote:


Not the same thing, but there's a modular electric system that might
meet your needs at:

http://www.yachtboutique.com/BugattiMarine/AEPS.htm

Steve

Actually, that's very interesting, thanks. After you sent me this link
I found another site that has much of the same information, www.feys.org.
That site at last puts a price tag, one of $73K, on a system with 4 x 133hp
electric motors plus a 400kW diesel generator.
Which in fact is exactly what I want - except for more generators, which
they say is an option in their system.

http://www.feys.org/System/our_system.htm

The price is actually lower than I expected and I suppose doable for
a ~30m steel ship that needs to be repowered anyway. Remains to
be seen if the figures they give hold up in reality though. Plus,
I don't suppose the price includes installation.

WHy 2 engines on one shaft.... you still have a single point of
failure... the shaft/wheel/tranny.

Why not follow Nordhaven.... single engine + a wing engine

OR

2 generators... 1 main electric motor + 1 wing electric motor.

no single point of failure

I worked in Helsinki at Wartsilla shipyard many years ago and all the
icebreakers and cruise ships use electric power.

Ed




Steven Shelikoff wrote:

On Fri, 21 Jan 2005 08:59:28 +0100, Y wrote:


On Thursday 20 January 2005 15:59, Steven Shelikoff wrote:


Not the same thing, but there's a modular electric system that might
meet your needs at:

http://www.yachtboutique.com/BugattiMarine/AEPS.htm

Steve

Actually, that's very interesting, thanks. After you sent me this link
I found another site that has much of the same information, www.feys.org.
That site at last puts a price tag, one of $73K, on a system with 4 x 133hp
electric motors plus a 400kW diesel generator.
Which in fact is exactly what I want - except for more generators, which
they say is an option in their system.

http://www.feys.org/System/our_system.htm

The price is actually lower than I expected and I suppose doable for
a ~30m steel ship that needs to be repowered anyway. Remains to
be seen if the figures they give hold up in reality though. Plus,
I don't suppose the price includes installation.


Actually, that feys site is the one I remember seeing years ago, googled
for it but the bugatti site came up first so that's the one I posted. I
think bugatti makes the systems feys installs so either one would be a
good resource. But you're right, I do like the feys site better. More
information there.

I don't think their price includes installation. But if everything
they're saying is true, installation should be a breeze compared to
installing a conventional engine. Probably a little harder than
replacing an engine in an existing installation but maybe along the
lines of converting from gas to diesel.

I'd like to hear your progress if you go with that system. I saw it a
few years ago and thought it was a great idea if I was ever going to be
a powerboater. But I'm a sailor and don't need that much power.

Steve