Chrome plated props.

[25931]

Is chrome plating a practical alternative to anti-foul ?

 

[vyv_cox]

I can't see any reason why it should be. Stainless steel derives its corrosion resistance from a layer of chromium oxide that forms on its surface, making it largely inert. Chromium plating does the same. Stainless steel prop shafts foul just as much as everything else, and chromium plate will probably perform likewise. I'm not aware that chromium oxide has any antifouling properties?

 

[25931]

My original question was too brief - what I was thinking about was the deterioration of the metal when not protected by anti fouling.

 

[vyv_cox]

I suggest you take a little time to ask exactly what you would like to be answered. Your second post doesn't do this.

 

[ccscott49]

My original question was too brief - what I was thinking about was the deterioration of the metal when not protected by anti fouling.

Antifoul does not protect the metal from deterioration, it just attempts to stop marine fouling. Normally anodes are used to protect the metal components underwater.
I think you have got mixed up here, or are mis-informed.

 

[tcm]

I am guessing that the OP wants to reduce prop fouling. I think a better solution could be to *copper* plate the props - the oxide layer than will deter crustaceans from taking uo residence thereon?

 

[vyv_cox]

I have read that copper plating manganese bronze propellers is not a good idea/doesn't work but for the life of me I can't remember why. It seems such a simple and obvious thing to do that there must be a good reason why not.

 

[tcm]

do let us know if u remember.

I recently had the boat out, coppercoat all fine, saildrive greeby after the original paint fel off, got replaced with other stuff by me so i used epoxy primer on the thing then what the heck, i coppercoated it. Yeah dissimilar metals hm, but there again the saildrive is full of dissimilar metals and plenty anodes and not too long in marinas.

So anyways my pal is looking at clever ways of applying the copper UNLESS u or others know different...

 

[penfold]

I have read that copper plating manganese bronze propellers is not a good idea/doesn't work but for the life of me I can't remember why. It seems such a simple and obvious thing to do that there must be a good reason why not.

Maybe to do with a lot of manganese bronzes not really being bronze at all, but posh brass. It's difficult to electroplate a homogenous layer of copper on, so you have porosity and an instant battery via the salt water with consequent rapid corrosion. I'll dig out my 'big book of marine corrosion for insomniacs' and see what it says.

 

[VicS]

I'll dig out my 'big book of marine corrosion for insomniacs'

It'll be interesting to know what your book says. There is not much difference in electrode potential between copper and manganese bronze to drive any corrosion.

 

[SailBobSquarePants]

Cool...

That's a very cool and useful chart. Very informative to those of us that don't study these things. Really stands out how different in potential aluminium is from so many other metals...

 

[VicS]

That's a very cool and useful chart. Very informative to those of us that don't study these things. Really stands out how different in potential aluminium is from so many other metals...

having just copied the diagram and not provded a link to the whole page i will just point out that the black bands shown for stainless steels refer to them in the non passivated state.

Google for "galvanic series" and you will find several other similar charts.