zincs Grounding systems

[Captlen1]

Trying to figure out where should zincs be used in bonding system. Thu ground plates or thru shaft? The boat I am Restoring has a ground strap attached to stern bearing housing then to zinc. Well with a bearing made of rubber it cant be grounded to the shaft and with gear oil in gear box how can the shaft get the ground. Should it be attached to grounding electronics plate?

 

[alan006]

If I understand your description correctly then I suggest you use zincs to protect both the stern bearing housing and all your other through hull fittings. I think its fair to say that bonding systems and anode protection has become much more important now that many of us have the shore supply always connected and use smart battery chargers.
You can use a brush system on your prop shaft to bond to the stern gland housing and then the zinc. Another way of course if you have the space is to use a shaft anode. You are quite right to be concerned about continuity through a hydralic gearbox. Sometimes you can test for continuity and get a good reading and then rotate the shaft say 90 degrees and get a poor reading.
I'm not sure if the grounding electronics plate should have its own anode as I have never seen one with an anode on it.
I hope this helps you.

 

[Peterduck]

It is difficult to give an answer without knowing more about what kind of boat you have. This forum covers the range between an 8ft clinker tender and a ninety-foot MTB; yours willbe somewhere in there.

It is wrong to assume that all boats need sacrificial anodes. Has it had anodes fitted in the past ? Have they wasted away quickly or slowly? Anodes, if fitted should be located in line-of-sight from the item which they are protecting, even if the electrical connection is inside the hull.
Peter.