Fizzing anode :-(

[B58]

An anode that is functioning in that manner usually means that there is a stray earth, earthing through your drive.

The alternative is that your neighbour has the same problem and is affecting your boat, this is quite common.

Contact Volvo and ask them for information regarding hull potential, this will determine if your boat meets their specs.

 

[Antony Collis]

I would also say should be zinc.
Why would you put an aluminium anode on an aluminium leg ?

If this question was serious you could go slightly further to ask why Annode manufacturers manufacture them at all....
It is answered above