As the photos show, top screw clip is undone jamming funnel into top of rubber tube, may have to use screwdriver to open up, then pour in oil, any oil, thicker the better. Put clip back in place.
Best to do this when still in water as oil sits on top of water until lift out, so is level around the bearing. Then move rudder to full extent backwards and forward when oil appears from top of rudder.
Odysseus
Bav 38