I replaced the rudderpost bearings a few years ago on my vessel. It is not impossible to do this yourself however one must carefully plan the work and have a helping hand or two when dropping and reinstalling the rudder. When you replace the bushings, do remember to provide for a way to get grease to the bearing to lubricate the bearing/shaft area as this was most likely the cause for premature wear. Before you start, take some rough measurements to make certain that you have enough room under the rudder to drop it completely out of the boat. It is sometime necessary to dig a hole in the ground to provide the clearance required, that is to say a shovel may be one of the tools you''ll need to do the job.