It just gets smaller and smaller...

[Matata]

My anode on my shaft is corroding well so I presume thats good. There are no other anodes on the boat ( sigma 33) except for the engine one. All the seacocks are bonded and so is the p bracket. Is there anything else we should do? We were thinking of hanging an anode over board while were away from our swinging mooring. If you feel that is a good idea how exactly is it done? lump of zinc attached to.... Regards Nik

 

[Pasarell]

I'm a little confused by your post. When you say the engine anode do you mean an internal anode in the engine or are you talking about hull anode? You also say your skin fittings are all bonded.
If you have a hull anode what else is it connected to? Current thinking is that you should not bond skin fittings to an anode, and if there is no anode but they are all connected together I suggest you cut the wires immediately. If they are connected together but without an anode then the least noble of them will become the anode for all the others and start to waste away. Galvanic corrosion only occurs when there are 2 dissimilar metals in contact with each other and with an electrolyte. If the skin fittings are not connected to each other they do not need to be connected to an anode. On most boats the anodes are just protecting the stern gear where, typically. there is stainless steel (shaft) in contact with brass (propellor).

 

[Matata]

The engine anode is in the engine block. We change it each year. There is no hull anode,but there is an anode on the stainless shaft as you sugest. The stop cocks are all bonded to each other and they go to the p bracket. Hope that helps. Ta for the help Nik

 

[vyv_cox]

If I remember another post of yours correctly, this is the arrangement that the boat has had for many years? If so, there's little to be gained by adding a hanging anode.

Theory says that bonding all your seacocks to the P-bracket is a bad idea, as something will corrode to protect everything else. So a hanging anode connected to your bond wire or something in the circuit might help as this will preferentially corrode, but it will be difficult to ensure that the anode can 'see' all the components.

If you don't have corrosion now I suggest you leave well alone, as you may unwittingly create a problem where none exists.

 

[Pasarell]

I'm torn between agreeing with Vyv_Cox and leaving well alone and saying get rid of the bonding wire ASAP. On balance I would still get rid of the bonding wire I think as it cannot do any good and I can't see what harm could come from getting rid of it. You are very fortunate if all the skin fittings and P bracket are exactly the same alloy and none are wasting away as an anode, even slowly. Have you checked them all for dezincification?
I don't think a hanging anode connected into that system would produce much benefit

 

[castaway]

I just don't know what to say ! I go around every 2 years and check that my skinfittings have bonding 'continuity' and now you say I have been wasting my time !

Is this like giving up smoking, drinking and not changing impellor rotors, all of which turn out to be good for your health ?

Nick