The invention relates to a pod ship propulsion System comprising a housing connected to a ship h\xfcll, an electric drive motor mounted inside the housing at least one propeller disposed outside the housing, wherein said electric drive motor is connected to the propeller by means a hydrodynamic gear. This configuration facilitates the use of a single infrared radiation source and a single detector for infrared measurements at two wavelengths, such that measurement errors may be compensated. The calculation unit selects a logical topology with the smallest sum among the logical topologies.