Retractable 360 propulsion unit for sailing yacht

[winchgorilla]

Hello to everybody,

I have only one last step before I officially become a Naval Architect, and that is to make a diploma project.
For a project I have take a 24m High Performance Racer/Cruiser, but because I like challanges and not to have the easy task, I have choosen an CBTF design with canting/lifting keel and lifting forward foil and ruder. Also in my design I would like to install 2 retractable rotating propulsion units, one in front and one behind because when the ship is in shallow water,rudder and foil should be a little bit retracted.
I'am searching for a solution like on Neriida, ex Wallygator (from Wally yachts), but the problem is that I can not find anywhere on the Net any name or firm which is producing such a unit, and the yachts which have this solution, they don't name it or mention it.

Everybody has a bow or stern thruster or there are some solutions with strong outboard engine with shortened Z-leg or something.
I have predicted that I need totally a 187kW of propulsion power, so I would this cut in two parts with one engine(Cummins,Yanmar) of 110-120kW and onother one with 70-80kW.

So please if anybody knows how to solve my problem, with retractable rotating bow and stern thruster/propulsion, tell me please. In my project, money is irelevant.

Also another question: Has anybody ever seen a system of retractable rudder, forward foil system? Also didn't find it on the Net (the hole system), just read about it, for some expensive sailing yachts. Any special advice.

[Vega]

Fisher-Panda are working on it. I is a diesel-eletric:R-DE PROP

http://www.whisperprop.de/E_1FEF7650...3003DC552.html

[usa2]

retractable forward foils are somewhat common, on the supermaxis Maximus, Nicorette, and Skandia. These are daggerboards with a trim tab though. I do not believe any CBTF yacht has a retractable canard. (Unless you count Stark Raving Mad, but she has the daggerboard/trim tab system, not a fully rotating rudder.)
You would probably need a drum which house the forward rudder, and the whole drum assembly would be rotated. It would be a slightly modified VARA system.

Good Luck.

[brian eiland]

Originally Posted by usa2

....You would probably need a drum which house the forward rudder, and the whole drum assembly would be rotated. It would be a slightly modified VARA system.

I mentioned this VARA rudder system on several occassions. Here's a web reference http://www.socasailboats.com/VARA_Sy...ra_system.html

Drive references:
http://boatdesign.net/forums/showpos...81&postcount=4
http://boatdesign.net/forums/showthr...3616#post33616
http://boatdesign.net/forums/showpos...14&postcount=7

Exciting New EPS Thruster (& Propulsion)
http://boatdesign.net/forums/showthread.php?p=65512#post65512

This firm has been producing a yacht with 2 retractable 360 propellors, i know they fabricated the round retracting shafts themselfes and fitted carbon fibre propellors from???.

This yacht was unfortunately destoyed during a fire on the since restarted yard.

They have no website and i cannot find more information on this yacht on the internet.

But this is the addes:

http://www.branchenbuch-niederlande....v--386836.html

[winchgorilla]

Thank you all very much on yours replays!
I will now follow the links and report you later how did it end...

Matjaz

[D'ARTOIS]

Hallo Johan, welkom op het forum, hoop dat je er veel plezier hebt......

Sadly almost nothing about Johan Vels work is to be found on the internet.

[D'ARTOIS]

Well, I thought you WERE Johan Vels. Therefore my hallo.

What would you like to know about him? Anything special? By my knowledge his shipyard is still in Medemblik after the fire that destroyed his shed.

I know about him from articles in dutch magazines, work on olympic fd's,etc. I met his Windshift yacht, whitch was in Yachting World, a couple of times on the ijsselmeer.

The yacht lost in a fire was to have diesel electric power driving 2 carbon props in retrectable shafts fore and aft.
Very interresting, i would like to know what happend to this design and how the yard is doing now.

[winchgorilla]

Hello,
I have check every adress and still there are some questions, but hopefully will solve them in upcoming days.

Also I'am interested in getting a little bit more information about John Wels work or his firm , web adress is not working ...

Has somebody any picture or tech info about the yacht or review how this system was operating(working).

[D'ARTOIS]

Johan Vels started some 20 years ago with the building of a woodcore AGARI (a very succesful Van de Stadt design, ever 2nd in the Sydney Hobart) and after a succesful launching he decided to start to make a building series of the AGARI and some other boats.
The AGARI is/was a very fast windward design of VdS and a very nice boat too. Close to ultra-light terribly fast and a boiat you could do everything with except ice racing!
Based on the success with this 40 ft design Johan became a pro boatbuilder and remained so till his shed burned off some years ago.

Tomorrow, I will be in Medemblik and I will investigate what has happened to Johan Vels.

[D'ARTOIS]

And yes, I have a few pictures of his boats in my archive. But it will take some time to get to them and you better wait till tomorrow when I am back from my trip.

[D'ARTOIS]

Ok guys here comes the design of the 40 ft AGARI

L = 11.99 mtrs
B = 4.00 mtrs
D = 2.00 mtrs

SA = 100 m2

Displacement 6380 kgs only

[brian eiland]

Originally Posted by winchgorilla

Also in my design I would like to install 2 retractable rotating propulsion units, one in front and one behind because when the ship is in shallow water,rudder and foil should be a little bit retracted.
I'am searching for a solution. So please if anybody knows how to solve my problem, with retractable rotating bow and stern thruster/propulsion, tell me please. In my project, money is irelevant.

Rim Drive Azimuthing Prop

When I look at these photos,
http://www.yachtforums.com/forums/23867-post8.html

and then the three below, I ask, isn't this the new future of azimuth drives??
The electric motor and the azimuthing propeller in a compact unit. And potentionally serviceable without hauling the ship.

...couple of other references
http://boatdesign.net/forums/showpos...9&postcount=11
http://boatdesign.net/forums/showthread.php?t=9432