Method 1
A conventional paddle wheel is submerged only partial, and only that part interacts with the water to produce thrust.
Apparently the same effect can be reached when a part of the paddle wheel is covered. That part does not interact with the water
as if the covered part would not exist (beside some remaining friction), even if the complete assembly is submerged under water.
Such a partially covered paddle wheel will work with horizontal and vertical axis.
This method can be used as bow- or stern thruster but also for propulsion.

Method 2
This method makes only sense with a vertical axis. The paddle wheel is no were covered, but the water movement,
that a rotating paddle wheel would produce, is restricted by a solid body (the hull) at one point.
That means: When rotating, the paddle wheel moves water to one side of that body, producing thrust.
It works also for paddle wheels with only two paddles ('RAKETE') and even with only one paddle ('AAL').
The bow thruster on 'MAX' is a mixture of methode 1 and 2.
The torque produced by this vertical paddle wheels also aids to steer the ship.
The 'RAKETE' and the 'AAL'- solutions are not at all an energy efficient method, but are simple,
can be used on nearly any ship design and can be quite powerful.

Bow Thruster