When I took our boat on land for some maintenance I found that the anodes on the saildrive were used up very unevenly. The anode on the saildrive looked almost new but the one on the propeller was completely gone. I suspected a fault of some kind here and started “troubleshooting”. But after reading up on both parts I found out, that it is actually a feature of the Volvo saildrive and the volvo folding propeller to be isolated against each other to prevent galvanic corrision.
Here my short video on it.
Syvsover 