There is a zinc anode on the Autostream propeller: do I still need a zinc anode on the propeller shaft?
Yes. The propeller has moving parts and non-conductive bearings, which result in a poor electrical connection of the various parts of the propeller to existing shaft anodes so we put an anode on the propeller to protect the propeller body and blades. The shaft anode is required to protect the propeller shaft and the propeller hub. Most problems associated with electrolysis in under water gear occur due to faulty electrical equipment on or around your boat.