Cathodic Protection/bonding advice

[petrolhead]

Puddleduck will likely give me a full answer here!

Our cruiser has only ever had shaft anodes on it's 40mm shafts, plus engine anodes and disc ones on the fixed trim tabs. It has worked well, although some years I have heaved a big sigh of relief when I see how close to being totally wasted and falling off the shaft ones are!

I am thinking of fitting a big hull anode whilst it is out of the water over the next month and bonding it later when it is back in, also putting on shaft ones as usual for now. I could fit two stainless steel studs sealed with sikflex onto which the anode could bolt outside and cables inside. Are there special studs or can I cut stainless rod?

I know an anode should see what it protects and i also believe ferrous and non ferrous metal should not connect to the same anode?

Here I see two problems, the hull shape of our boat does bot really suit an anode underneath unless off centre due to a long keel and centre board. I could fit it low down on the transom but it wont "see" the sterngear.

If I bond the sterngear, p brackets, rudder stocks and engines/gear boxes so as to protect the shafts/props there will be all kinds of metals in the loop.

Any help appreciated.

[puddleduck]

Hi Russ, wait until we're back from Ireland and I'll go through it all step by step - certainly worth doing if your shaft anodes are only just getting by. Screen looks brill on Penny Too - we must discuss purchase of same now!!

all best,
c.

[johnny11]

There are two types of pipeline cathodic protection, galvanic and impressed current cathodic protection. What is the difference between them?