From Apple translate - We have a tree oil leak not on the front side but on the back side. Can we do it without taking out the boat? Has anyone ever done it?
I don’t know what tree oil is (thanks Apple), but from your arrow it looks like we’re talking about an oil leak from the back of the bell housing / front of the transmission? If so I see no reason the boat should need to come out of the water. The prop shaft may need to be disconnected from the transmission and maybe slid back a few inches to make room to move the transmission, but that can be done in the water.