Al has a wealth of information and experience with these Hunter rudders. For instance, for my 1994 Hunter 40.5 the rudder shaft was stainless-steel but the fins that attach to the shaft and in effect, actually turn the rudder when you rotate the shaft were made of carbon steel. Who knows why they used carbon steel, but they did. So, if you get water into the rudder, the carbon steel fins can corrode. This was evident when water leaked out of the bottom of the rudder, it was rust colored. When they rebuilt my rudder, they used stainless steel fins. There are very few people who know more about Hunter rudders (and probably other manufacturers) than anybody around.