I had the harbor crew use a Travel Lift to put the boat up on jack stands such that the bottom of the keel was 3 feet off the ground.  Then using a wood saw (not as a saw but a thin tempered steel bar) to carefully remove the rust between the centerboard and the trunk.  This took about 3 hours.  Large chunks were broken off up to 1/8 inch thick.  Finally the rust was clear and with several up and downs, the centerboard was free and operting smoothly.
Using an angle grinder, I ground down all the rusted areas that I could get to.  Then the whole centerboard was wire brushed.  This was a fun job, especially since the temperature was in the high 90's.
Harold oversaw as I apply the primer to the centerboard reaching as far as I could up into the trunk.
I continued with the primer until the whole centerboard was done. 
I returned the next day and applied the finish coat.  While waiting for this to dry I cleaned and refinished most of the brightwork.  When done it was a pleasure to feel the smooth action as I cranked up the centerboard.

Well now we are almost ready to sail.