Cathodic protection on copper bottomed boats

[mulligan]

I have recently refurbished a 60 year old timber yacht which has been copper sheathed to the water line. The copper was cut out around where the anodes were affixed to the hull and it appears that originally only two things were connected to the anodes, i.e. the engine and the shaft. I am now at the stage where I am putting in a new connecting wire for cathodic protection, and would welcome any advice with regard to installing this to toilet seacocks, keel boats etc. especially taking into account the copper sheathing.

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[vyv_cox]

I would suggest that any form of cathodic protection with your setup is at best redundant and at worst harmful.

1. No engine will ever be protected by an anode outside the hull. The throwing power of an anode, without impressed current, is limited to about 6 times the diameter of the suction pipe. Anyone who thinks they are preventing engine corrosion by these means is deluding themselves. Do people really believe that electrons circulate from the engine, down a wire to the anode, through the seawater outside, up the suction strainer and the suction hose, through the pump impeller and back to the engine?

2. A shaft anode is an excellent investment. It protects the propeller and some of the shaft. Nothing else.

3. Why is there water around your keel bolts? There may be a little seepage but cathodic protection won't help with that.

4. If you fit Blakes bronze seacocks you have no need to protect them with anodes.

5. It has been stated here many times that using anodes on a wooden boat can create a whole host of galvanic problems. Best advice is don't use any.



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