uneven strut anode wear

[Richard19068]

I have disk zincs on either side of my prop shaft strut. They are connected together and fastened to the strut with a single stainless bolt through the two separate zinc pieces and the strut.

They come as a set and both are always replaced at the same time, typically by my hull cleaner while the boat is in the water. The disks normally wear at about the same rate and since they are connected together I always assumed that they should.

A disk on one side is now nearly completely eaten away while the disk on the other side is in good shape.

Any ideas as to why now they have the uneven wear?

Thanks

 

[Don S/V ILLusion]

You must have bought the left handed model.

orientation of boat w/r current, unequal conductivity to metal to which it is connected or manufacturing defect

 

[Richard19068]

You must have bought the left handed model.

orientation of boat w/r current, unequal conductivity to metal to which it is connected or manufacturing defect

Well, it is the port side that is bad....

No river current. Pacific ocean.

I thought the connection of the two pieces via the stainless bolt would equalize the conductivity. Maybe not?

Maybe the bad one does have a manufacturing defect.

 

[Hayden Watson]

Stainless is a poor electrical conductor so the connection of bare bronze to zinc is the primary path for stray current. If one side was cleaned to bare metal and the other was not, that would cause the uneven erosion you are seeing.