Well guys, all good things must come to an end and it is officially time for us to sell Soul Rebel. We are simply at a point in life where we do not have the time or resources to accommodate such type of boating--as such, we have purchased a live aboard sailboat and will eb focusing our efforts...
I appreciate you taking the time to share your knowledge with us! Piecing the puzzle together, it is clear that those powered trim sender wires are a clear corrosive hazard. @tpenfield had a similar corrosion issue and also had trim sender wires in the water judging from the pictures.
Good advice, but I'm like 99% sure I solved this. Keep in mind this was not "my slip," but transient ones that we were at for like four nights at one place and five at another. This boat is not, nor has ever been, slipped beyond a few days. The corrosion was never present in salt or brackish...
The corrosion on the gimbal ring is definitely corrosion and not pitting or scale. I believe the source to be the loose, dangling, and formerly-powered trim senders wires which are right next door (and have been since disabled).
Either way I have now disabled them. Seeing as the corrosion was closest to the wires, I believe this was the issue: while running, 12 volts were applied and a "battery" was created causing the electrons to flow from the open circuit into the non-conductive freshwater to the least noble metal...
Thinking more about this, I think you are on to something. @tpenfield linked his thread where he added an anode to his gimbal ring because of similar corrosion issues. In that thread, someone also pointed out that he had broken/detached trim sender wires which would supply 12 volts with the...
I think you may be on to something here--especially since the magnesium anodes which are installed correctly are doing essentially nothing. I have thought maybe I got zinc by mistake so I will check that as well. For next season, I will go back to running aluminum anodes--they can't possibly...
My understanding of this chart is that the more active anode (magnesium) should protect better in pure freshwater like the Great Lakes (Lake Michigan and Superior)? Even the one aluminum anode on the prop shaft also isn't corroding!
