Very hard to do in the H20
In order to pull the bearing while in the water you'd need a scuba tank set up because of the amount of time it takes to aleign everything. You'd have two options. Try to remove the bearing from the front by forcing the bearing out the back and removing the prop. This is very hard to do. I tried it on my boat when it was on the hard and couldn't do it.The second option is to drop the rudder, plug the rudder post bearing (it probably won't leak because it should be above the water line), split the shaft/transmission coupling, remove the flange, pull the shaft, plug the shaft tube (it's below the waterline and will sink the boat if you don't plug it and I doubt your bilge pump could keep up with the flow You'd be suprised the amount of water a 1" hole in your boat will let in.). Next you have to get the old bearing out. the quickest way is to cut it lengthwise while in the strut with a hacksaw blade and then curl it out with a plier. Not easy when you're under water. Next you have to put the bearing in with a press tool. This takes a little time especially under water.I guess that you could do it but...ADVICE: A good yard can short haul your boat and replace the bearing in an afternoon. Hope this helps.