Crazy anode saving idea...?

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ChasB

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So, anodes corrode because they're the 'noblest' metal in an electrical circuit immersed in water and so will slowly disappear to nothing...

But what if you attached a wire to your boat's earth, and dangled something made of an even ignobler metal alloy into the water. Wouldn't that be the thing that corrodes, and your boat's anodes would be left uncorroded?

Now, either that's a really dumb idea, or else everyone else is already doing it and no-one told me... /forums/images/graemlins/mad.gif
 
It does work ,i have seen a boat with a lump of zinc on a wire with a crocodile clip onto the propellor shaft. Im not sure what metal you would need to use that would go before your anodes,Im sure someone clever will tell you before long /forums/images/graemlins/smile.gif
 
You are on to something here, I suggest gold, that conducts really well, probably never need to change the anodes again! /forums/images/graemlins/wink.gif /forums/images/graemlins/grin.gif
 
Gold is way down the periodic table - that's why it's so valuable, it doesn't corrode.

What about sodium, potassium, or lithium?
 
Hoping I have not been sucked in here but giving all the benefit of the doubt.
Free hanging anodes are a comon add on - wired back to the item you wish to protect.
We used to hang four around an old aluminium yacht we once had - and I still use a big zinc hanging one when parked up to help minimize loss on our current saildrive anode.
JOHN
 
[ QUOTE ]
You are on to something here, I suggest gold, that conducts really well, probably never need to change the anodes again! /forums/images/graemlins/wink.gif /forums/images/graemlins/grin.gif

[/ QUOTE ]You'll need to replace them all the time because I'll be along with my dive gear to nick them. /forums/images/graemlins/laugh.gif
 
But it has to be more active than your current anodes? Or it will work in reverse and promote corrosion, yes? So ideally the very most active anode material you can buy?
 
er no - the less noble is attackd first, the most noble last of all. So dangling gold etc will do nothing if there is bronze etc.

You need to dangle as much less-noble metal over the side and this needs to be "visible" (line of sight as underwater) to the stuff youactually want to protect ie props and rudders, and connectd to that stuff too.

I saw a nice clever anode on a classic yacht recently - a dangling anode over the side but with the wire hidden inside the braid of an otherwise olde piece of rope
 
"magnesium and zinc: in fresh water magnesium is least noble, in seawater it's zinc."

How does that work?

Anyway, you'd want something less noble than your current boat anodes wouldn't you?
 
For your delectation and amusement, I present the 2.36kg hanging anode as presented by Zincsmart.com, at a very reasonable £36.31

grouper.jpg
 
Rather than using a less noble anode such as Zn or Mg) to protect the more noble prop one could use sufficiently high external voltage applied to an anode to oppose the natural electrochemical voltage created by the anode, the cathode (your prop) and seawater cell. It should only be a few volt or so as one doesn't want to plate the protected metal!
 
That's a neat idea. Does anybody do that?

Hey, you could take it a step further and have marinas provide their own charged pontoon anodes to protect all the vessels that choose to plug in...

(just kidding - I can see what's wrong with that!)
 
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