Deposits on propeller

[Geitz]

We are on Lake Michigan and just this season moved to a different marina. Previously, every year at haul out, the prop shaft, prop and anode were always clean. Last Friday, we hauled out and the prop and anode were covered with a thick layer of crusty material. It looks like coral only not quite as pretty. The pressure washer removed most of it from the prop. Also, there's weird "trails" on the hull above the prop shaft and the prop. The bottom paint is VC-17.


What's going on here? (sorry about the links to Onedrive. I couldn't get the images to attach to the posting)


https://1drv.ms/u/s!AhJvC2-V7kbdlAeWsWa_b9CPa80d
https://1drv.ms/u/s!AhJvC2-V7kbdlAVx5X1D9CIG70mE
https://1drv.ms/u/s!AhJvC2-V7kbdlAjqYFttCwa_k2Af

[Geitz]

Maybe I posted to the wrong forum..............




I spoke to several people and the consensus is that another boat at the marina was leaking electricity and my boat was acting as the ground (earth, cathode), which explains the collection of material as opposed to the loss of material. I've since purchased a galvanic isolator, which I've learned are made for this problem.