Minesweeper class "Minensuchboot 35", 1937
This minesweeper class was designed in 1935, and is apparently equipped to lay mines as well. Notice the unusual propellor, which appears to be a Voith-Schneider propellor. Only the ships designated M1 and M2 of this minesweeper class carried this unconventional propellor, however.
This device appears to be a merry-go-round of paddles arrayed around the circumference of a spinning disk that feather as they revolve. I think the intent of such a design was to allow the ship to direct its thrust in any direction without having to change the direction of the main motor spinning the disk (the only thing that would have to change is the phase of the feathering cycle of the paddles). In this way, the ship would be permitted great maneuverability and didn't even require a rudder!
Thanks to Stephen McLaughlin for identifying the propellor type and to Andrew Smith for information on which units may have used this equipment..
Design drawings for unit M102 of this class can be found here.
Photos taken of the wreck of M26 (sunk off Cherbourg on May 15, 1942) may be found at www.plongee-anges.fr.
There is more data on this class at German-Navy.de.