angles and leads to a groove 500 embodied on the outer surface of the hydrodynamic plain bearing 50 the infeed opening 300 of the supply conduit 30 communicates with a feeder conduit 20 provided in the planet carrier 2 so that it is possible for a lubricant pump not shown in detail for example the usual lubricant pump that is provided inside the underwater transmission to supply a flow of lubricant via the feeder conduit 20 into the individual supply conduits 30 which is explained in greater detail below on the side oriented away from the planet carrier 2 the hydrodynamic plain bearing 50 and the planet gear 5 supported on it are secured by a thrust washer 51 to prevent them from shifting axially on the planet axle 3 the drawing also shows a part of the housing 12 of the underwater transmission and an accompanying housing cover 120 which jointly fix the ring gear 4 of the planetary gearing during operation of a thusly designed underwater transmission for a rudder propeller when at a standstill there is a static friction between the plain bearing 50 and the planet gear 5 supported on it if the rudder propeller is then to be set into operation for example the drive shaft 10 and the subsequent parts of the underwater transmission are to be set into rotation then first a corresponding control command of the rudder propeller control unit pushes a flow.