Exciting New EPS Thruster (& Propulsion)

[brian eiland]

The results of the Design at METS awards, announced at this morning's
Breakfast Briefing, appear to prove that the wheel can be reinvented
according to the Jury, who named the EPS Silent Thruster from Van der
Velden Marine Systems of the Netherlands as the overall winner.

This product redefines the bow thruster, eliminating the usual arrangement
of a central hub and gearbox. It instead uses exchangeable blades that are
connected to an outer ring; this floats on ceramic bearings and is powered
by an integral motor in the casing. The solution is elegant, well designed,
and promises a number of advantages over conventional concepts
_________________________
....from their website...

In addition to fixed thrusters they are now working on retractable systems as well as
utilizing the concept of the EPS as a means of propulsion !!

[brian eiland]

When I saw this new technology this morning my thought drifted back to some patents I had collected a number of years ago when I was researching some alternative marine propulsion drive systems prior to my command of a computer....just good old looking thru the stacks of patents down at the patent office.

I'll post a couple of these, and maybe someone will update this subject thread with more examples obtained by computer wizardry.

I imagine that one of the primary technologies that allow this new 'peripheral
drive' to come into being is the fantastic new ceramic bearing technologies.

Examples:
1) Patent #3,487,805 Jan 6,1970
PERIPHERAL JOURNAL PROPELLER DRIVE

2) Patent #5,181,868 Jan 26,1993
JET PROPULSION DEVICE FOR WATERCRAFT.....AND CIRCULATING PUMPS

[brian eiland]

Originally Posted by brian eiland

....I imagine that one of the primary technologies that allow this new 'peripheral drive' to come into being is the fantastic new ceramic bearing technologies.

As I look a little closer I still do not see what "EPS" stands for??....maybe 'electronic pulsed system'

Maybe the bearings aren't all of the technology that has allowed the emergence of this new propulser. It appears as though the preipheral drive power is an electric motor of some sort integrated into the outer ring. This would make sense with all of the new talk of diesel/electric systems.

[brian eiland]

Over on another forum there appeared this notice of some other work on "Rim-Driven Propeller" units

[brian eiland]

I originally posted a notice of this 'exciting new EPS Thruster' award under the Diesel Electric Propulsion subject thread, but I thought it might do to cross-link the subject threads as this thruster (bow) technology might well lead to propulsion technology. I noticed also that the EPS subject was rather more difficult to find on their website so I've attached their PDF file. (opps, had trouble uploading file....you need to go to their site and go to "news", and click on "EPS Silent Thruster")

From the latest issue of The Yacht Report there is a new product news release. "Voith told Project 2004 delegates last year of an impending sea trial experiment using VSPs (Voith Schneider Propellers) for roll stabilisation; the "VSR" concept. Although not currently available, the results must have been satisfactory as they will supply their first Platform Supply Vessel (PSV) with VS units to both propel and stabilise the 85m vessel. The stabilisation works under way and at anchor or rest. Ever technically innovative, Voith is also entering into a commercial cooperation with another innovator, AIR Fertigung-Technologie GmbH. AIR have sold composite automatically adaptive pitch Carbon Fibre propellers to the superyacht market, but will now offer electrically rim driven propulsors from 0.2 to 200 kW. These can be transverse or azimuthing thrusters, or main drive pods azimuthing or fixed. Their transverse thruster strongly resembles the Van der Velden EPS rim driven thruster. This is apparently not coincidence as Dirk Bucher of AIR told me that the two companies were until recently working together on that project."
http://www.voithturbo.de
http://www.air-composite.com

I underlined that one phrase as it caught my attention that this technology might well morph into propulsion units after thrusters.

[Guillermo]

Brian,
I find this EPS thing as main propulsion very interesting for a variety of boats and ships. Here a more direct link to the Rim Driven Thrusters you mention:
http://www.brunvoll.no/Web/resources.nsf/0/0F5A219AA75C9EC4C1257083002E22F7/$FILE/Brunvoll_developes_RDT.pdf

I find the RDT specially interesting for big stern trawlers like the Danish one attached. Main Engine power for this ship is 4860 kW and total electric power staggers to a huge 4996 kW! Of these, 3060 are driven by the main engine.
I believe the use of diesel electric in conjunction with one big RDT may bring great advantages for this kind of ships.

[brian eiland]

That's a very interesting document. I suspect that the one area that is going to be most demanding in the development will be the bearings. They quote;

"The bearings of the RDT are designed to eliminate the need for lubrication oil and there are no dynamic seals. Hence, the bearings, which are both magnetic and hydrodynamic bearings (with patents pending), are designed to minimise maintenance costs and eliminate any oil pollution."

I suspect, but don't know, that these might be some sort of ceramic bearings. Just think of the thrust loads imposed on the 'ring' supporting the blades that must also maintain electro/magnetic tolerances, and often in 'dirty water'!

[Guillermo]

Yes,
The question is what's the upper power limit with this technology. They have tried 100 kW, but when we are talking about 5000....(?). Very interesting matter, deserving a close follow up for next improvements and bigger models developing.

[brian eiland]

Looks as though there are a few players in this technology, and Brunvoll appears as a front runner having done some considerable big scale prototyping and testing.

Interestingly it appears as though the relatively new permanent magnet electric motor technology has driven this new interest in rim-drive propulsion. From Brunvoll," the development of RDT has been triggered by market demand for an increased number of ships where both the main propulsion units and the manouevering thrusters have electric motors with variable speed drives. In this context the RDT offers a number of advantages."

So rim drive propulsion is advancing right along with the thruster development. Brunvoll has worked together with the company Norpropeller to test a novel drive system for variable speed electrically driven propellers. This system involves the use of variable speed permanent magnet generators and PM motors. The design implies that the prime mover, the diesel engine, can be run as in a traditional system, as if the engine was direct mechanically coupled to the propeller, but not requiring a reduction gear, nor a battery storage source.

Brunvoll is planning to market the RDT for ships and larger craft, while Norpropeller will focus on the market for smaller craft

Another player, AIR Fertigung-Technologie GmbH, that have sold composite automatically adaptive-pitch Carbon Fiber propellers to the superyacht market will now work to provide electrically rim driven propulsors from 0.2 to 200 kW.

Lets add some pictures of the Brunvoll test unit.

[nero]

kinda thought the advantage of having a battery bank meant that the diesel engine could be small in size.

In 4 years they should have it all worked out for my catamaran. fingers crossed.

[brian eiland]

Originally Posted by brian eiland

....Another player, AIR Fertigung-Technologie GmbH, that have sold composite automatically adaptive-pitch Carbon Fiber propellers to the superyacht market will now work to provide electrically rim driven propulsors from 0.2 to 200 kW.

I received a PDF document from this company just the other day, and it certainly looks as though they are persuing the smaller unit sizes we might utilize in yachting vessels verses commerical boats, 4-100kW.

From the PDF, "The Inline Thruster, as a compact unit, can be installed subsequently at any time as a bow or stern thruster, or soon as main or auxilary drive"

I noted from the PDF document you sent me previously, "the mounting of the rotor is realized by proven water lubricated floating bearings...".

I did not detect any substantial indication on the drawings of proper thrust-load bearings?? These bearings are going to see much higher loads than the peripheral bearings.

And in the case of a main or aux drive unit, as opposed to the thruster units, both of these bearings are going to experience more 'heated operation' as a result of the continuous rather than intermittent loading. Can you comment on these questions and/or offer any discussion of these bearing problems/details.

Your 'floated box' solution to the servicing accessability looks very nice.

[brian eiland]

Originally Posted by brian eiland

I noted from the PDF document you sent me previously, "the mounting of the rotor is realized by proven water lubricated floating bearings...".

I did not detect any substantial indication on the drawings of proper thrust-load bearings?? These bearings are going to see much higher loads than the peripheral bearings.

And in the case of a main or aux drive unit, as opposed to the thruster units, both of these bearings are going to experience more 'heated operation' as a result of the continuous rather than intermittent loading. Can you comment on these questions and/or offer any discussion of these bearing problems/details.

An email response from the manufacturer brought this;
"Concerning the bearings we had developed a special bearing with different functions. It is mainly designed for the continous loading of the thrust. It has no problems with the continous loading typical for propulsion units. The intermitted loading is covered by another bearing and optimised for this. At the drawings you can not see the details."

and, "The inline jet is an electrical rim driven propulsor. At the moment we offer this system in two sizes. The third size will start in this year. It can used for thruster applications and propulsor applications as well as retractable installations."

[Guillermo]

Maybe the thrust bearings issue is why they are limiting power for the time being. I'll try to get more info from them to know their plans to develope higher powers, as it would be a nice propulsion system for modern stern trawlers and other fishing and work vessels.

[Deering]

What happens with this unit when a log or other debris goes through it? What's the failure mode?

Seems to me that if an object gets sucked in, all of the carbon fiber blades get wiped out and you're dead in the water, vs a prop that might get dinged up but still provides limp-home capability.

[Guillermo]

Just to inform that on March the 18th I wrote to Brunvoll the following message:

"....I've known about your Rim Driven Thruster trough Boatdesign Forums and I'm very interested in knowing more about the system, as I find it may be applicable to stern trawlers and other fishing boats, as well as tugs, work boats, etc.
I see the power goes up only to 100 kW and I would like to know if you have plans to go up in the range. Is your thrust bearing system able to cope with higher loads?
I would appreciate very much your kind answer. Thanks in advance."


No answer till now.