Howdy again! A while back I hauled out my H 37 and I noticed a great deal of electrolysis pitting on the feathering prop. Since this seemed to be a new problem, I was concerned that my prop was being eaten by a new condition in the marina where I stay, or a new condition on my boat. There are rumors that the Elliot Bay Marina has "hot spots" so I had them come out and perform an electrolysis reading of the boat and the surrounding water (including my neighbor's boats.) Everything seemed OK until he checked the rudderpost. Much to my surprise, my rudder was not grounded. The steering pedestal was OK...... go figure. So, I set my voltmeter at .5 volts DC to check for tiny voltage differences between the rudderpost and the aft shroud, and the stray current pinned the voltmeter! There was a reading of nearly 1.5 volts between them! Free power if you don't consider a $1,500 prop every 2 years into the equation. Solution: Since it was confirmed that the ground system of the boat was good including the shrouds, I made up a jumper wire and attached one end on the inside of the transom to a through bolt on my aft stay chain plate. The other end went to the rudderpost. I placed a stainless steel hose clamp around the rudderpost to avoid drilling a hole for a screw. I simply placed the wire between the clamp and the post with enough slack to allow for the rotation of the post. That was about a year ago and the pitting has stopped completely. Conclusions: I had hauled the boat out 3 years ago and had a new stainless steel prop shaft installed to replace the old bronze one. At that time, I serviced the prop and heavily greased where the blades connect to the prop housing. I am not sure if the new stainless shaft had anything to do with my problem, but I assume not. However, greasing the prop blades where they connect to the prop housing in effect isolated the blades from the ground of the shaft. The blades were on their own to deal with a non grounded rudder with stainless steel components that, in a perfect world, were sealed from the salt water. However, I know the rudder has some water intrusion and I believe that this may have caused an electrolysis cycle that rapidly eroded the blades. Zincs on the prop shaft were no help. Now that the rudderpost is grounded, I have seen no further pitting on the prop blades. I dive the boat about every 4 months and all looks good. You might want to perform this simple test on you boat too! Just hook up a voltmeter to your rudderpost and any other grounded metal object on the boat. You should read zero on the meter.