New Propulsion Devise

[nero]

Maybe this is the future?

http://www.spw-gmbh.de/eng/hb/index.html

Cost should be going down when production starts.

[Sander Rave]

I see installation advantages over conventional drives.
Large volume production builders can install this propulsion on the last moment.

What's the price? It's a nifty little device and I think this will never be cheep. I love it though. The same controlabillity in your sail racer as a harbour tug :-) No drag when out of order.

[Guillermo]

I also like the idea, seeming to have a lot of advantages, but I'm wandering why don't we see this system already around. They tryed a workable model of the thing at least in 2002, and you find almost nothing about it in Internet (Except some in German, that unluckily I do not understand), so...
Maybe is there a problem related with the end plate blade's bearings (or pins or whatever) wearing away too soon and so making the plate unstable and maybe even making blades to broke away...?
Is there a patents problem...?
Or...?

[Sander Rave]

Anyone correct me if I'm wrong, but this system is around. Only problem is we don't see it when the ship is used properly ;-) It's under the ship in the water.

Here you can find some english information on the system. Didn't go into details, so maybe there are some differences.

http://www.voithturbo.de/vt_en_pua_m...deDevelopm.htm

[Sander Rave]

Just for our asian friends: Some info on types of propulsion in Korean. Neatly designed site though!

http://www.kordi.re.kr/chongseo/vol8/vol8_09.asp

번영, 번창, 융성, 성공

[tom28571]

Our local ferries use the Voith-Scheider propeller and it works very, very well. The main attribute is maneuverability since it can give full thrust in any direction and can change direction without changing speed. The negatives seem to be complexity and cost. Adding the retractable feature can only add to complexity and cost. Wouldn't help on a racing boat since the rules would penalize such a system to equalize the rating anyway.

Would be nice though.

[Guillermo]

Originally Posted by Sander Rave

Anyone correct me if I'm wrong, but this system is around. Only problem is we don't see it when the ship is used properly ;-) It's under the ship in the water.

Here you can find some english information on the system. Didn't go into details, so maybe there are some differences.

http://www.voithturbo.de/vt_en_pua_m...deDevelopm.htm

I know Voith-Schneider system has widespread applications the world around since quite a long time now. I'm meaning this particular HÜBNER-BRAUN propeller application. I have not seen it around nor heard of it till today (Well, this may mean nothing, of course, other than I'm not updated)

[JonathanCole]

Some potential issues for this drive. A fishing line (or anything else) wrapped around the vanes would completely disable the drive, since the vanes have to pivot on their axis. However if you attached three very sharp wire hoops outside of the vane swept area, such problems could be largely avoided. Or maybe the trailing edge of vanes themselves could be sharpened.

The best new anti-fouling drive I have seen is this hubless design intended to be a thruster, presumably for intermittent use.
http://www.yachting.nl/news.php?m=3&cod=33
But streamline the housing and put it on a shaft that can rotate 360 degress and design the device for continuous use and you have the best propulsion concept I have yet seen.

[Sander Rave]

Dear Guillermo,

The main problem seems to be an invester to take this product from prototyping to production model.

I scanned the trial report of the Bavaria testcase and it seems to me (regarding to the number of ten pieces that is quoted many times as minimum for a production series) casting of the different parts is the bottle neck.

The unit needs a vertical space of approximatly 700-950mm. Top speed for this prototype was 5kts, only because of overheating the electro-drive (but hey, we're talking prototyping here)

Further more, the price of a unit will be the same as a saildrive, plus the price of a HÜBNER-BRAUN unit. They state the price will be only a minor setback regarding the advantages. The unit can without great expenses be switched from a saildrive as stated below.

Der Preis sollte annähernd vergleichbar werden, mit dem Preis eines
Sail-Drives plus dem Preis eines Drehflügelpropellers. In Anbetracht
der vielen Vorteile des Antriebes, sollte jedoch der derzeitige Preis
keinesfalls als Nachteil angesehen werden.
Der Sail-Drive kann sehr leicht gegen einen HÜBNER-BRAUN
Antrieb ausgetauscht werden, ohne das große Zusatzkosten der
Installation anfallen würden.

If you need specific information translated, just let me know. (just don't expect me to translate a german service manual for a Tomakak ;-)

[Guillermo]

Thank you, Sander Rave. Heating may be solved, of course.
I find this propeller system very interesting for a diesel-electric installation.
I hope developers can solve their financial problems and bring the thing into production.
Anyhow I'm concerned with this end-plate thing. Tugs applications of Voith-Schneider propellers have an end plate to protect blades and minimize end of blade tip vortexes, but in this case plate turns with the blades. Mmmm....
Have a look at: http://www.cd-adapco.com/press_room/.../21/voith.html
I see you are in Amsterdam. Nice city. I go there from time to time because of the Banjers Gatherings.

Jonathan:
I like the EPS thruster as a bows thruster or fixed propulsion thruster with helms. Maybe encapsulating it and making it to rotate will make it very expensive.

[nero]

The proposed drive is sized to replace the hole left by a saildrive. Perhaps a larger diameter would have better efficiency for a displacement hull. Maybe a larger at less rpm the blades will be stressed less?

For my cat (future) I am not looking to cruise with power. Need enough power to get me in and out of ports, let me cheat while changing tacks, and help get out of the way of something bigger.

[JonathanCole]

Originally Posted by Guillermo

Anyhow I'm concerned with this end-plate thing. Tugs applications of Voith-Schneider propellers have an end plate to protect blades and minimize end of blade tip vortexes, but in this case plate turns with the blades.

Guillermo,

Do you know anything or a source of information about how a rotating plate like the one on this drive affects the hydrodynamic resistance over the surface of the plate? In other words, is there more or less hydrodynamic resistance over a rotating plate verus a stationary plate?

Originally Posted by Guillermo

Jonathan:
I like the EPS thruster as a bows thruster or fixed propulsion thruster with helms. Maybe encapsulating it and making it to rotate will make it very expensive.

Everything is expensive until economies of scale kick in. If you build ten units its expensive. If you build ten thousand units its less expensive. If you build ten million units its dirt cheap. But if you are trying to build the ultimate propulsion drive unit, something like EPS or Hübner-Braun could replace current technologies because of the exceptional directional control. The more boats and ships there are, the more crowded the docking facilities become, and the more precision directional control becomes important. I like the idea that all drives should double as bow and/or stern thrusters. I have seen propulsion pods on cruiseships that have tremendous directional control. It would be great to have that kind of thing on all boats. I definitely want it on my solar electric catamaran. Precision directional control, especially electric drives, could be used together with GPS for anchorless station-keeping.

[Sander Rave]

Guillermo,

Thanks for the complement! Just give me a sign when you are around. For the plate thing, I guess it's for hydrodynamics when retracted. Maybe it's a structural thing, but that's further fetched.

[Guillermo]

Originally Posted by JonathanCole

Do you know anything or a source of information about how a rotating plate like the one on this drive affects the hydrodynamic resistance over the surface of the plate? In other words, is there more or less hydrodynamic resistance over a rotating plate verus a stationary plate?

I'm not sure at this moment. I have to study it.

[TomE]

Very interesting topic this is! I live close by one of the big oil terminals in Norway (Mongstad), where the harbour tug mentioned in the Voith Turbo is in use. I have never got the chance to look deeper in to the boat but I have heard some talk about it.
The mayor advantage is, as my name brother says above, is the ability to freely turn the direction of thrust. My impression is that the tug has two drives, located midship one on eache side. Combine this with a decent power source and the enormous surface area of the blades and you have yourself a serouis boy-toy.
It's an amazing view to watch them bringing in some of the worlds bigges supertankeres - the tug is just a speck beside them, and still have the thrust needed to control them safely in.

I have heard some funny stories/rumors that they have been accidents where there have been used too much thrust when pushing the tankers close to the quay, and the bow of the tug has pierced/damaged the side of the tankers. Not soure wheter this actually happened, but there is some seroius power at tap, and do precice manouvers faster than all of their competitors.

However; I consider this to be a system with limited use - is has it's advantages with regads to low speed, high thrust applications. As with harbour tugs and thrusters. It just has to be perfect for DP reliant vessels (dynamic positioning)! I don't expect this system to give high enough efficiency to compare to traditional propellers in straight line performance.

In my opinion the (close) future lies in a propultion system based around the fish-tail principle. One that can exploit a vessels movements in rough sea to contribute to the propultion of the vessel. I knoe there has been done some promising research and development by a Norwegian inventor, and probably by others around the world as well.

In the more distant future I'm hoping for exlploitation of (magnetic) fields to push the vessel trough the water withot any movable parts. Maby "forced field cavitation" can be a term? I'm mostly carried away in dreams and Sci-fi now, but I consider magnetism to be a mystery that will give LOTS of new technology when solved.

Other opinions and views?