You Can Do It!
Dave and Joe's advice is very good and over the long run, probably works best for the task and available free time. However, you can do it yourself. While taking care of a severe blister job this summer, I also tackled the cutlass bearing. There was just enough play in the shaft to be too much to let the job go to another season. Reading Don Casey's "This Old Boat" was very helpful - primarily in how to disconnect the shaft from the transmission. The first thing was to remove the prop. With a pipe wrench carefully gripping the shaft between the shaft strut and where the shaft enters the hull and a large socket wrenh on the prop nut, loosen the prop nut. The prop is on a tapered portion of the shaft at this point. Most likely, it won't simply slide off. I used a gear puller with extended gripping arms and the prop came loose. There will be a 1/4 inch bronze key inside the prop-to-shaft section to also make sure you collect. If your anodes are still on the shaft, take them off also. Inside your pride and joy, is the first of two "more time-consuming/not really difficult jobs in the exercise: taking the shaft off the transmission. You simply have to get down on your knees at the backside of the engine compartment (remove the companionway ladder), remove the aft bilge access board, loosen the stuffing box components using two very large open ended wrenches (I used average size pipe wrences) so that the shaft will be free to slide out the hull once you do the next step. Remove the engine compartment boards above the engine and open the rear engine access door. With plenty of light, scribe a tick mark across both the flange on the end of the shaft and the matching flange on the transmission side as a reattachment reference, take a socket wrench to the three bolts on the flange at the engine end of the shaft and remove them. Once removed, (the stuffing box should already be loosened) the shaft will come free of the transmission and back away enough to add the spacers inside the flange and rebolt the shaft back onto the transmission (read Don Casey for the full story about this step). The reason you are doing this step is because the shaft is pressed into the flange so tight that it doesn't just slip out. The flange also has a keyway with the shaft, about 1/4 inch square bronze and a set screw to further hold the shaft and flange together - naturally, loosen the set screw so that the unbolt/rebolt exercise will work. You will probably have to unbolt, insert another wedge thickness (I used small nuts and washers that were wrapped in tape so they wouldn't become part of whatever else may be lurking below the engine/bilge area) and rebolt ten to twenty times. It is a test of patience and great satisfaction once you have accomplished the task. I don't know, but it seemed like an hour or two to do this task. Have some good CD's on in the background and a beverage. Eventually, the shaft does come loose from the flange and will be free to literally slide out the rear of the boat. Now you can finally work on the cutlass bearing. I tried to carefully knock it out but it was "permanent". Several discussions with other yards, etc. convinsed me that a hack saw was the way. Set the blade of a hack saw inside the shaftway and evenly, carefully cut thru the rubber and then barely a 1/32nd to 1/16th of an inch - not quite through the wall of the cutlass bearing bronze tube. When you are almost through, you should be able to pry the tube into itself and it will separate from the strut's hole. There! The sawing took about a half hour. Now you can put it all back together again in reverse order! Clean-up the strut's hole with 200 grit paper so it is fresh and clean. More than likely, your new cutlass bearing will not just slide into the strut. I have, as was mentioned by the other response, heard of freezing the bearing and then, in its contracted state, sliding it in, but I didn't have a freezer available. My solution was to use a short section of a strong pipe clamp (3/4 inch size pipe), set the bearing in position at one end of the strut, add a protective board across the other end of the strut and across the free end of the bearing and begin to tighten the clamp. It works very good. Oil the bearing and strut often, reposition the clamp as needed and keep at it till the bearing is fully in place. Toward the end of the clamping step, I used a pipe wrench as a lever on the pipe clamp turning handle to make the tightening job easier. This took me a little over an hour to tighten the bearing into the strut. There, you've just replaced your cutlass bearing! At this point, your satisfaction level will rise quite a bit. The rest of the job is to simply put everything back together again. When I got to the part of putting the shaft back into the flange, I polished the shaft at the area that presses into the flange and oiled it up. The shaft wouldn't quite go in all the way. What you do not want to do is beat on the end of the shaft at the prop end. Inside the boat, one can carefully tap the flange toward the shaft with just enough swing room in the engine compartment. It will go on and be at the right position to bolt back onto the transmission. Check your shaft alignment once it is all bolted back together. Read Don Casey's book about this and if whether or not the engine mounts need to be adjusted accordingly. Overall, it is a lot of work, but you do get to learn another aspect of your boat that doesn't come along every day. I enjoyed it as a "therapeutic" alternative to my day job and if I ever need to do it again, I will. One thought that did go through my mind was how do people do it when their engine isn't as convenient to access as on the Catalina 30? Good luck!