Anode protection

[europe172]

I have two anodes, one on the hull and a smaller shaft one . The one on the hull is eroded but the shaft one is barely eroded.
question
Is the hull one enough or could there be another reason the shaft one is not disappearing

 

[emmalina]

Your shaft is probably isolated via the coupling

 

[Tranona]

It should be the other way round as the shaft anode is closer to the prop. However you don't say what the hull anode is connected to. Normally it will be bonded to the shaft via the gearbox and possibly a bridging wire across the coupling if that is the flexible type.

That is the wrong place to fit a shaft anode. It should be 20mm or so in front of the p bracket. Where is is now is restricting water flow through the cutless which could leaf to premature wear. It is also a rather odd type. The more common type is like this anodeoutlet.co.uk/shaft-anodes/ It is important to have exactly the right size as the liner of the anode is what makes the electrical connection.

I note you have a folding prop - does this have its own anode?

In principle the only thing that needs protecting is the yellow metal prop from the stainless shaft, and possibly the prop against the stainless pivot pins (and gears if 3 blade). A prop shaft anode should be enough to do this.

 

[europe172]

It should be the other way round as the shaft anode is closer to the prop. However you don't say what the hull anode is connected to. Normally it will be bonded to the shaft via the gearbox and possibly a bridging wire across the coupling if that is the flexible type.

That is the wrong place to fit a shaft anode. It should be 20mm or so in front of the p bracket. Where is is now is restricting water flow through the cutless which could leaf to premature wear. It is also a rather odd type. The more common type is like this anodeoutlet.co.uk/shaft-anodes/ It is important to have exactly the right size as the liner of the anode is what makes the electrical connection.

I note you have a folding prop - does this have its own anode?

In principle the only thing that needs protecting is the yellow metal prop from the stainless shaft, and possibly the prop against the stainless pivot pins (and gears if 3 blade). A prop shaft anode should be enough to do this.

Thanks @Tranona
I will fit a new anode of the type you suggested before the p bracket .
never considered the water flow aspect before.
no anode on the folding prop, the shaft is titanium not stainless but they are very close on the scale .

 

[vyv_cox]

Can I ask how you come to have a titanium shaft? That's a new one for me.

 

[europe172]

Can I ask how you come to have a titanium shaft? That's a new one for me.

I used to work in aerospace, there was some “spare” 25mm rod which a couple of us used for shafts

 

[Tranona]

Thanks @Tranona
I will fit a new anode of the type you suggested before the p bracket .
never considered the water flow aspect before.
no anode on the folding prop, the shaft is titanium not stainless but they are very close on the scale .

I suspect you probably don't need an anode at all, especially if that prop is a Flexofold. Suggest you investigate where the hull anode is bonded to as it may have nothing to do with the shaft and prop.