Ships earth connection

[catmandoo]

Anybody know if you can use the zinc anode connections as boat ground plate for radio and boat side AC earth instead of separate expensive ground plate .

Already have RCB,galvanic isolator separate neutral and earth on shore supply and in 240 V AC boat circuits

Zinc anodes in contact with water and connected to boat via SS bolts through hull so seems logical earths

 

[rob2]

I guess you only have to consider whether you can accept hooking your antenna to the negative pole of the battery. Does that constitute an earth in antenna terms? Everything I've read (though not understood) about ground plates suggest that the sea is the ultimate as it has better conductivity than real earth and the contact is improved by surface area, so a thin plate is ideal.
Personally I would be inclined to try it and see - which always seems to be the answer with propagation!

 

[William_H]

There is every reason to believe that zinc is just as good as copper at forming an earth plate. However it is the exposed area that contacts the water so you might need a few anodes. ie compare the area of your anodes with the area of the suggested earth plate. Of course your running gear (prop and shaft ) should also provide some surface contact with water.
I have read that 2 square feet is a useful target for lightning protection ie current diversion and perhaps similar or less for SSB radio or mains power earthing.

Of course if there is any residual current flowing into the water ia the anodes or prop gear then you may accelerate the corrosion. But then that is the cade anyway. good luck olewill

 

[MarkGrubb]

If my memory serves, Nigel Calder's book suggests that the circuits for the electrical earth and the anode bonding should be kept seperate. If not a fault may cause high residual current, as mentioned by the previous post, which could accelerate anode corrosion. Fine if your anode is big enough, not so good if you don't realise until you next lift out or dry out: anode eaten and propellor turning brittle as its eaten by the propshaft.