Mystery Ship Component

[Letum]

http://www.b3tards.com/u/57a418c694bc7c6296b3/whatisit.jpg

Above is a section from a drawing of the aft of a WW2 German Minesweeper.

Can anyone identify the strange component with the prongs?
You can see them from the plan view here:
http://www.dreadnoughtproject.org/plans/KM_Minensuchboot_35_1937//M1-2_zwischendeck_stauungsplan_100dpi.jpg

What are they and how are they used?
Thanks.

[Tchocky]

Looks like a Voith Schneider propeller to me. Highly maneuvrable propulsion device, useful in the "HOLY SH*T STOP RIGHT NOW" world of minesweeping.

http://en.wikipedia.org/wiki/Voith-Schneider

Edit - Hang on a minute, does that picture show them to be above or below the waterline? And they're a bit canted...

I wonder.

[Raptor1]

Ugh, beat me to it!

[Letum]

Ahh! Thankyou!

[Raptor1]

Edit - Hang on a minute, does that picture show them to be above or below the waterline? And they're a bit canted...

I wonder.

Definitely below the waterline. The blueprints don't show the waterline.

Also it seems to have 2 of them from the blueprints on the Dreadnought Project.

[Letum]

Edit - Hang on a minute, does that picture show them to be above or below the waterline? And they're a bit canted...

Just below.
It also explains the lack of propeller and rudder on the diagram.
ed: and the drive shafts going to them!

[Tchocky]

You're right, guys. In the plan view you can see the engine shafts going to each thruster. (edit - beaten to it!)

I didn't know that this kind of technology was in use back then. Respect Kriegsmarine +1

[Syxx_Killer]

I remember Robert Ballard mentioned those in his book The Discovery of the Titanic. His research ship had two of them. They worked great to keep the vessel in place while they dropped the ROVs and stuff. In the book they called those things egg beaters.