[Viceroy]

I suspect a great deal of attention would have to be directed to the prevention of galvanic/electrolysis action in massive electric propulsion applications...particularly bonding and insulation. Not being technically astute, I wonder if there an advantage of AC or DC applications in this regard? Cheers, Richard.

[bvimatelot]

Earlier posts mentioned "immediate Full Torque". Whilst this may be desirable occasionally (although, with forethought and common-sense, shouldn't be necessary too often) surely its going to put a huge strain on a classical straight shaft? Possibly also on a "podded" drive - but I dont know enough about the drive train to comment. In any event, I'd have a drive-shaft saver fitted in there somewhere...

[AMG]

Originally Posted by bvimatelot

Earlier posts mentioned "immediate Full Torque". Whilst this may be desirable occasionally (although, with forethought and common-sense, shouldn't be necessary too often) surely its going to put a huge strain on a classical straight shaft? Possibly also on a "podded" drive - but I dont know enough about the drive train to comment. In any event, I'd have a drive-shaft saver fitted in there somewhere...

I guess the meaning of full torque is quite the opposite. Meaning you can have the prop turning very slow, with torque, but since we are in water the impact on shafts and pods are almost nothing. (Even a slow reving diesel gives a higher prop rpm at idle.)

[brian eiland]

Just recently an associate sent me this note,

"On December 26th the first production catamaran, a 43ft Leopard to be
chartered in the BVIs by Moorings, with the Glacier Bay diesel electric
system left Cape Town for Miami. They hope to display it a the Miami
Boat show in February.

It has the same 2 x 35hp electric motors as Asanagi but only one of the
25kw gensets. Therefore the motors are only powered as 2 x 16hp motors.
Usually the 43ft Leopard is fitted with 2 x 30hp Yanmars with a top
speed of about 7.5kts. With the electric motors their top speed is about
8.2kts"
______________________________
On another forum I remembered this posting,

Originally Posted by Originally Posted by cyclops

What is the complete cost and eff. of any electric powered boat when you add in the pollution and cost of burning fuel at a powerplant to generate electricity, transmission losses and repairs, cleaning the plants gases. Most people do not add in the battery companies costs and pollution either. Each time energy is converted it loses some eff. Do a oil in ground to prop turning eff. study and anything electric loses out. Electric power is a very wastefull form of power. And I like electrics.

I think you would do well to read these two PDF's http://boatdesign.net/forums/showpos...65&postcount=5 This DC technology in generation and usage promises a lot less in losses than you traditionally think of. And the 'battery' storage capacity does not have to be that great as the generator source may only need to be run at just the level required by the motors unlike AC systems in general

Diesel-Electric Propulsion for Sailboats

[YachtForums]

Azipods acclaimed as a success aboard superyacht Air...

By IBI Magazine.

The superyacht Air, the first yacht equipped with Azipod propulsors (in the form of a pair of 2,500kW Compact Azipod units), has successfully completed an initial six months of operation, as Azipod manufacturer ABB Marine reported recently.

Describing the yacht's trials, ABB Marine said the results of the initial trials with the Compact Azipods — steering trials — were extremely successful, and subsequent sea trials showed many of the benefits of the Azipod podded propulsor, particularly when leaving the dock for the first time.

"With one Azipod ahead and one angled outwards at 90 degrees the vessel moved off the dock smoothly with increasing speed and then pivoted 180 degrees about midships with impressive thrust from the Azipod units forcing the stern around," said the yacht's chief engineer Steven Lloyd in the most recent issue of ABB Marine's The Frontrunner, published late last month.

The company said that the lack of noise and vibration was also noticeable, both from the Azipod motor and the propeller.

Air has cruised extensively since departing the Lürssen shipyard last year, and has cruised from Bremen to the Northern Isles of Scotland, down to Palma and on the Mediterranean. "In all this time the Azipod drives have proven to be extremely reliable, and cruising has proven to be very comfortable with the low levels of vibration, even at higher speeds," said ABB Marine, noting that it was looking forward to "more installations in yachts in the very near future."

(3 January 2006)

[kiwicapt]

Yacht AlumerciA was fitted with Schottel STP200 azimuth drives back in 2000. After 5 years and 60,000 miles we have had no problems.
There is no vibration through the hull and manouverability around the docks is better than any conventional drive system.

Cruising the Pacific northwest was a concern due to logs but after hitting a couple we realised that they were as safe if not safer than conventional props.

As far as comparisons, remember that conentional propellors lose 15-20% efficiency due to the angle of the shaft. With Azipods, there is no loss.

True, they are more expensive to install but Maintenance costs are near zero. Companies like shottel have been making azipods for over 50 years for the commercial industry so they know what they are doing.

[Codger]

Kiwicapt, thanks for the information. Deadhead strikes are a concern for me. No leakage or deformation issues after your mishaps at all?

[KCook]

Also, are the props on the AlumerciA foreward facing (ala Volvo IPS), or at the rear of the pod?

Thanks,
Kelly Cook

[Codger]

Kelly
I believe that the STP are only dual prop.
http://www.schottel.de/eng/r_produkt...uebersicht.htm

[KCook]

WILD! Both front AND back!

Thanks Codger,
Kelly

[Go5go]

It is interesting to see the longevity of this thread....

I was kind of taken back after reading the articles on Ice (ex Air) as the first installation of an AZIPOD system. In the sense of a DE type vessel I suppose, but the z-drive type pods were used on the M/Y Fantasy out of the Broward yard in the early nineties.. I had not known AlumerciA had a similar type set up.

Fast Electric Yacht Systems (www.feys.org) has done some smaller boat installations, with the claim of same speed and performance with one Primemover on a DE system as opposed to 2 Primemovers on a convensional system. Thus using less fuel. And the torque factor at any prop rpm....

I spoke with someone there a while back as they were developing a newer system with accomodations for larger vessels.. Im thinking of a sportfish with excellent backdown and trolling capabilities since any prop rpm can be selected. I have not seen any updates to the site or new literature on this though..

It would be nice to see a little primer on some basic DE design for yachts, as in a conversion type. I dont know if should I be just converting a 2000hp system into KWs directly or are there additional factors.. I only ask as the FEYS site has something to this respect.

DE sounds very interesting for flexibility and the efficiency that it can provide. I only hope that our office might get a chance to do some work in this area. Thanks to everybody that has taken an interest to post good bads and the uglies too.

Cheers,
Pete

[brian eiland]

Glacier Bay, Inc.'s OSSA Powerlitetm propulsion motors win Sail Magazine's Freeman K. Pittman 2006 innovation award

Sail Magazine has announced the winners of the 2006 Freeman K. Pitman award for innovation in the sailing industry. OSSA Powerlite synchronous dc neodymium permanent magnet propulsion motors received an innovation award in the systems category.


OSSA Powerlite is a family of new diesel electric propulsion gensets, motors, and house load integrated power systems for yachts that provides a new standard for quiet, fuel economy, flexibility, and simplicity.
OSSA Powerlite electric propulsion motors turn a propeller independently of the speed of a diesel engine in a genset. This allows the prop and the engine to run at their most efficient speeds independently, and without the additional cost, weight, and friction of a transmission. The result is better performance and major fuel savings.


For more information and the updated website on Glacier Bay’s OSSA Powerlitetm system see:

http://www.ossapowerlite.com/

Dear Colleagues---I am interested in powering a full displacement (10,000 pounds) hull at 6 knots---this will require just under 10 horsepower---I would also like to be able to hang on the hook for a few days, so I need to recharge my batteries---no major electrical loads except for some minimal refrigeration---can anyone point me in the right direction to a manufacturer/fabricator who would be willing to help me with this project?---Thanks for your kind assistance, Cal.

[rcrapps]

I remember a magazine article years ago about some guy putting in Siemens electric motors driven by a single gen set in a 35ish foot boat. He replaced his original mains, used the same inboard Prop shaft.
The article also said this person was to develop it more and start a re-powering company.
Anybody remember this article or know where that company went?

Thx, Ralph

[Go5go]

That sounds like the Fast Electric Yacht guys as posted earlier.. www.feys.org check this sight out.. wouldn't know if they are actually still in production. I had a large pdf of an article of an installation they did.. I'll see if I can dig it up.