Water lubricated bearings with metric inner and outer ø. Brass shell. Rightward involute (R) bearing for lefthand rotation propeller. Leftward involute (L) bearing for righthand rotation propeller. The shaft no longer rotates in a polygonal support, but is supported and guided over its entire circumference, thereby reducing vibrations. The shaft rotation promotes a powerful pumping action in the involuted channels, which leads to a considerably increased fluid velocity in the channel and remarkable cooling, lubricating and cleaning effects.