Podded propulsion

leonidas · 03-02-2006, 11:49 AM

We are currently evaluating different propulsion systems for a 45 m semi-displacement hull form newbuilding. We have quite a lot of experience with the conventional shaft-fixed or cp propellers -rudder configuration, modearte experience with water jets, but not at all with azimuthing pods. Any input or suggestions from the readers is most welcome.
We think that CRN Shipyard at Ancona has already built yachts with this system.

Ken Bracewell · 03-02-2006, 12:13 PM

I have not had any experience running an aziod on a yacht, but there was a Royal Denship in Florida last year on which I saw a steady stream of new captains and even more yacht painters fixing scratches!

Codger · 03-02-2006, 12:36 PM

Leonidas
This thread may be of some help.
http://www.yachtforums.com/forums/te...ropulsion.html

There is much interest in these propulsion systems but the amount of easily available first hand information on real world use and reliability has not been sufficient for one to make a decision. If you do come across more, please share.

YachtForums · 03-02-2006, 12:38 PM

We have thread on DE propulsion that discusses pods too. Thomas Hackman from ABB Marine (Azipod) is a member of YachtForums and I'm certain he could offer some insight. Here's the thread...

http://www.yachtforums.com/forums/te...ropulsion.html

YachtForums · 03-02-2006, 12:39 PM

Whoops! We posted at the same time Codger.

Codger · 03-02-2006, 01:04 PM

Quote:

Originally Posted by YachtForums

Whoops! We posted at the same time Codger.

Just goes to show that there are at least two of us with a keen interest in this particular subject. " Pods, got to go read this NOW!"

Crewagency · 03-05-2006, 03:48 AM

The Royal Denship did not have Azipods on Board it was a Schottel Propulsion.
www.schottel.com It looks like Azipods but the e-engines has to be installed inside the boat.

I placed an Engineer on a new Benetti with Azipods and will contact him for some technical details. I only know that the first seatrails are very successfull.

Also the new Lürssen ICE ex AIR sails with this " new " technology.

I think the only problem with AZ is that if a problem comes up you must drydock to check the Engines but most of the latest passanger ships use this and they sail normally more than a Yacht and most of them without any problems.

Also ICE is able to sail only with the schottel browthruster in the next harbour with a maximum speed of 2-3 knots if the main propulsion did not work.

wdrzal · 03-08-2006, 07:10 AM

Am I wrong or is the term azipod just refer to a thruster(propellor) mounted on a pod so it can turn (azimuth)360 degrees. how the pod is driven does not matter or where the motor is located. ABB marine and schottle are just company names who produce different drive mechanisms for their azipods. one direct and the other with shafts and gears and pinions.

Azimuth is the horzontal componate of direction.

Crewagency · 03-08-2006, 07:32 AM

I think there are many different solutions for the Azipod propulsion.
1. We have the ABB Azipods where the electric engine is integrated outside directly in the Pods and the power comes from gensets located inside via cables.

2. Then we have the Schottel Twin Propellors where normal Engines
are installed with normal shafts and a special gear to the outside pods.

__________________________________________________ _______________
1 Picture below :
This presentation features the ABB installation on a 65m Yacht under construction at Azimut SpA - Benetti in Italy. The Ambrosia III is due to be completed in mid-2005.

The main generator sets, two Caterpillar 3512B, rated at 1200 kW, 1500 rpm, and two Caterpillar 3408C rated at 300 kW, 1500 rpm, are located midships. The smaller gensets are placed in a soundproof compartment and used for station keeping and idling speeds up to 9 knots.

ABB Marine Deliveries 2004 :

* Main Switchboards, 690 V, 50 Hz
* 2 x 1070 kW Compact Azipod Propulsion
* Distribution Transformers and Filters
* Integrated Machinery Automation Systems
__________________________________________________ __-
2nd Picture below
The SCHOTTEL Twin-Propeller (STP) is the successful optimization of the complete Rudderpropeller system with an efficiency up to 20% higher. It is the ideal means of propulsion for all vessels in the medium speed range with application-related higher propeller loads.

Two propellers mounted on a common shaft and rotating in the same direction, with guide fins integrated into the complete system, result in a host of advantages, including high reliability due to the straightforward construction with a small number of moving parts, reduction of the propeller diameter without penalising the efficiency, lower fuel costs and low maintenance requirements.

K1W1 · 03-08-2006, 08:26 AM

Hi,

I think you are going to be wasting your time fitting Azipods to a 45m yacht.

They take up a lot of room with the switchboards etc and in my opinion are just too much for a smaller yacht.

wdrzal · 03-08-2006, 08:35 AM

Yes, I know how they work,but you made the statement that royal denship did not have azipod propullsion which it does,right? Any pod that turns is a azipod, since the azi comes from azimuth, as long as the pod turns,does not even have to be 360. RD just has schottle azipods.

Doesn't the schottle turn?

og.marinov · 03-08-2006, 09:08 AM

Quote:

Originally Posted by leonidas

We are currently evaluating different propulsion systems for a 45 m semi-displacement hull form newbuilding. We have quite a lot of experience with the conventional shaft-fixed or cp propellers -rudder configuration, modearte experience with water jets, but not at all with azimuthing pods. Any input or suggestions from the readers is most welcome.
We think that CRN Shipyard at Ancona has already built yachts with this system.

Hi Friends,
I am curious, why so late the azipods starts to be object for discussion too late. The main advantages, of such kind of propulsions, are applicable of the power yachts.

leonidas · 03-08-2006, 11:56 AM

Quote:

Originally Posted by K1W1

Hi,

I think you are going to be wasting your time fitting Azipods to a 45m yacht.

They take up a lot of room with the switchboards etc and in my opinion are just too much for a smaller yacht.

You are probably right. Hence the need for evaluation from all angles including that of space, weight versus increase in hydrodynamic efficiency. Makers claim a 10 to 15% improvement over conventional shaft/bracket/propeller and rudder configuartion.
In case any reader wishes to do further research, here some more information in the web:
www.abb.com
www.air-composite.com
www.marinelog.com/DOCS/PRINT/mmipods.html
www.nautican.com
www.omnithruster.com
www.roll-royce.com/marine/default.jsp
www.schottel.com
www.vdvelden.nl

Codger · 03-11-2006, 12:56 AM

Leonidas
I have no reason to doubt the claimed increases in hydrodynamic efficiency.
Whether or not overall system efficiency is increased is another question.
As you stated, total propulsion system weight as a percentage of the total vessel would have to be one question answered. The one clincher if going the diesel electric azipod route could be the opening up of options as to powerplant placement and therefore weight distribution and perhaps the placement of ancilliary systems. Just throwing a thought out here, but that versatility may actually be just as important in a 45 metre vessel since configurations might make a significant difference in the overall space utility available. Not being tied to a direct shaft might make noise and vibration control easier and more effective with a potential increase in the overall reliability and longevity of the entire craft.
I'm just looking at an unrelated project and the added cost and complexity due to vibration just in fastening systems would be halved if vibration were not an issue as well as adding significantly to estimated MTBF.

Innomare · 03-11-2006, 10:55 AM

Hi Leonidas

to answer your initial question:

I am a big fan of the azipod system as I know it from ABB. I can't speak for other systems on the market as I have no experience with them.

I wouldn't bet my life on it, but I would be extremely surprised if it was a valid choice for a semi-displacement motoryacht (regardless of the size we're talking about). The main reasons are the added weight and the added hydrodynamic resistance.
The weight is not a point in most displacement yachts, as it located low and actually good for the stability. In a semi-displacement yacht however, every ton counts and usually you don't want to make them any more stable than they already are.

The resistance of the propeller hub and motor is also a far more important factor at semi-displacement speeds than at displacement speeds.

I am sceptical, but if you want to investigate these systems, I'd focus on the Schottel system, as they have more propeller area for less underwater drag...
So far, I haven't seen a single pod on anything else than a displacement vessel.

Bruno
Naval Architect
Innomare

PS azipod is actually the brand name of ABB's system, like Rolls Royce have the Mermaids. In general we should speak of "azimuthing podded propulsion systems".