Diesel Electric Propulsion

MacMcL · 11-17-2005, 10:58 AM

Passage Maker Magazine recently did an article on a DE retro fit to a smaller vessel (40'or 50") using motors to turn the props as opposed to pods. Quite interesting, and they intend to follow up with future coverage. Seimens seems to be the leader in providing the equipment right now.

brian eiland · 11-17-2005, 11:58 AM

Thanks Godger

Those bearing failure references were interesting, but lacked some details. The reports stated that there were 2.5 foot dia bearings that support the shafts, but failed to mention the trust bearing sizes or types, even while it stated, "The bearings are apparently failing under thrust loading."

I find it somewhat difficult to understand that the peripheral bearings would fail under thrust loading. I find it much more likely that the thrust bearings would fail, as they are being asked to absorb both forward and rearward thrust loads. Possible the 'lips' of the peripheral bearings are being used to absorb the thrust loads, and these are too small in total area as a design effort to keep the overall diameter of the pod to a minimum. But even this doesn't make sense as the motor unit is already a bigger diameter itself.

Note that these podded designs house an electric motor that must be sealed against the sea water, as well as the likely hi-capacity bearing lubrication medium. The electric motors of the newer generation 'peripheral drives' is a permanent-magnet DC unit that is not being isolated from the sea water, nor are its bearings.

thomhack · 12-16-2005, 08:05 AM

Hi all,
I just joined this forum. A quick note to make sure that you have seen the feature in issue 69 of The Yacht Report ?

http://www.theyachtreport.com/Articles/TYR69myair.pdf

Send me an e-mail, if you want more info.

Regards to all,
Thomas Hackman
ABB Marine
thomas.hackman@fi.abb.com

YachtForums · 12-16-2005, 12:31 PM

Hi Thom,

Thanks for joining.

Lurssen has diligently persued permission to publish images of AIR, but to no avail. We had hoped to cover some of the technical achievements in the form of a feature review. If this comes to pass, I hope you'll be able to share some insight.

Glad to have you aboard.

Carl

thomhack · 12-22-2005, 07:55 AM

Carl,

Just send me a line and I´ll try to help you.

Merry Christmas to all.
Thomas

bulwark102 · 12-22-2005, 07:31 PM

There is a Nordhavn 72 currently being built with DE propulsion, go to nordhavn.com for details.

Their conclusion so far is that it will be more expensive to build, but can be more fuel efficient by being able to more accuartley match power generation to the speed of the vessel, there is greater redundancy as all engines including the generators are potential power sources.

Perhaps one of the most interesting points is that full torque is available as soon as the propeller starts turning, which should help when docking.

It will be interesting to see how it performs.

AMG · 12-24-2005, 03:57 PM

A member of the YachtForums asked me to make a "Highlander green" version of my 70 m design Polara. Also to add a couple of ABB Azipods.

And since it is Christmas, his wishes came true...

Texas_Dragon · 12-25-2005, 12:36 AM

Beautiful, Lars! Thanks!

Texas Dragon

Arniev · 12-25-2005, 01:52 AM

Awesome ...

Texas_Dragon · 12-25-2005, 02:20 PM

Lars,

I've searched the forums and have found what seems to be your first posted rendering of the 70 Meter Polara Explorer. Do you also have the general arrangement for the decks that you show for many other of your designs?

I'm drooling at the thought!

Texas Dragon

AMG · 12-25-2005, 04:22 PM

Sorry, I have made no complete plans on yachts bigger than 180 feet. Here are the outlines for the decks if you would like to draw them in yourself...

As many yachts, this one can also be diesel electric with shafts instead of pods. I am not sure what I should build today, it would be nice to have some first hand reports from the yachts now launched with Azipods.

/Lars

thomhack · 12-28-2005, 11:08 AM

Lars,

The feature in The Yacht Report #69 includes a first-hand report on the sea trials and first months of operation, made by Steve Lloyd, the Chief Engineer. I can send you a copy by e-mail, if you wish.
Also, I can prepare for you a power plant spec (with equipment dimensions and weights), if you want to fit it into your GA. Just give me some more details on the power requirements for the Polara Explorer.
Nice design, by the way. The non-bulbous bow tells me she is ice-classed. What class ?

Regards,
Thomas Hackman
ABB Marine
thomas.hackman@fi.abb.com

AMG · 12-28-2005, 11:19 AM

Thanks Thomas, I´ll contact you by e-mail.

On the ice-class, since she has no buyer yet, I don´t know. But you are right, with this bow she can break pretty heavy ice, with removable stabilizers and ice eating props fitted...

Mark in SBA · 12-28-2005, 01:23 PM

I've gotta laugh at all this "new" technology.

All the anticipated cost savings these technologies are supposed to realize go up in smoke with the first unscheduled dry docking. There's nothing intrinsically "neat-O" about DE, and it's been used landside in locomotives for decades, albeit in moderate horsepower applications. The real technology driver for DE isn't the mechanical stuff - it's the solid-state motor controls.

DE makes sense for the cruise liners because it consumes less space, offers better siting flexibility within the hull, and can be tailored to reduce vibration by operating the engine within a narrow band. The downside to the azipods is 50% of the drivetrain is sitting outside the hull.

I'm with Codger - traditional shaft and in-hull AC motor setup. The slight loss in prop efficiency is made up with the ease of inspection and maintenance.

brian eiland · 12-28-2005, 02:05 PM

Quote:

Originally Posted by Mark in SBA

I've gotta laugh at all this "new" technology.

All the anticipated cost savings these technologies are supposed to realize go up in smoke with the first unscheduled dry docking. There's nothing intrinsically "neat-O" about DE, and it's been used landside in locomotives for decades, albeit in moderate horsepower applications.The real technology driver for DE isn't the mechanical stuff - it's the solid-state motor controls.....

I'm not an electrical wiz, but I believe a substantial portion of the 'new technology' in this realm relates to the use of DC systems rather than AC systems. And the use of permanent magnet motors and generators. This makes some of the new technology "neat-O".