Shaft anodes

[RCsailfast]

When we got our boat it had a 2blade fixed prop and we were using magnesium anodes on the shaft. After upgrading to the feathering prop, which uses an aluminum anode. I had contacted PYI about magnesium anodes and they don’t make them.

The Admiral is questioning my choice to have magnesium on the shaft with aluminum on the prop.
Never thought too much about using mixed anodes but wondering if I should just use all aluminum? I felt the magnesium added extra protection but it looks like a pine cone after the fall pull out. The aluminum one is just slightly pitted. Who knows maybe the Magnesium one is preventing the aluminum from doing its job. Or if I have an anode on the prop do I really need one on the shaft?
I hate when the Admiral starts messing with my twisted logic

 

[Frank Langer]

The usual advice is to not mix anodes, ie. use the same anodes everywhere to keep them from dissolving each other. I think aluminum anodes work in both salt and fresh water, so if I'm right, I would use aluminum on the prop and on the shaft. Just my opinion.
Frank

 

[Mike_W.]

We have been using magnesium because we are in fresh water. If it pine-cones then it is doing what it is intended to do. If it doesn't then something else probably is. Since you have a magnesium anode the aluminum one on the prop is probably not really doing anything - which is a good thing. We finally launch next week and I'm thinking of leaving last year's anode on and getting a second year out of it. Have you seen what they charge for these things?

 

[RCsailfast]

I am really leaning to replace the magnesium with an aluminum one so they aren’t fighting each other like Frank said. The aluminum one on the prop does get eaten a bit but think the magnesium is pulling the load and may be over “zincing”

 

[Solarken]

When we got our boat it had a 2blade fixed prop and we were using magnesium anodes on the shaft. After upgrading to the feathering prop, which uses an aluminum anode. I had contacted PYI about magnesium anodes and they don’t make them.

The Admiral is questioning my choice to have magnesium on the shaft with aluminum on the prop.
Never thought too much about using mixed anodes but wondering if I should just use all aluminum? I felt the magnesium added extra protection but it looks like a pine cone after the fall pull out. The aluminum one is just slightly pitted. Who knows maybe the Magnesium one is preventing the aluminum from doing its job. Or if I have an anode on the prop do I really need one on the shaft?
I hate when the Admiral starts messing with my twisted logic

I use only Zinc on everything

 

[Loren Beach]

We boat in fresh water, and changed to aluminum 5 or 10 seasons ago.

 

[Second Star]

The list below might help. Al isn't very far from Zinc and Mg Does the prop have beryllium in it? in it?