Zincs Gone

[Sailgunner]

I have my boat behind the house on a canal and have noticed in the last year or so that Ihave to replace my shaft zinc every two months. I always kept my shore power connected to the boat. I disconnected the shore power and the problem seems to have gone away. My conclusion is I am the problem and not one of my neighbors. Any recommendations on where to start trouble shooting my grounding problem?

 

[Charles Erwin]

Measure your hull potential shore power connected and disconnected, charger on and off, other AC circuits on and off. Same routine with DC circuits. If you do this eventually you will find the culprit. If you don't do this you will only be guessing.

Although rare it is possible that you have an AC short or maybe an AC safety green/white (neutral) connection somewhere on the boat - like a microwave, air conditioner, coffee maker, automotive type battery charger. Maybe even a wiring goof on the dock itself.

So confirm there is no AC in the water because AC returning to ground through the water is a serious threat to people - in addition to promoting the rate of zinc wasting.

Charles

 

[Stu Jackson]

You might want to wander into a West Marine store and look at Nigel Calder's excellent book: Boatowners Manual for Mechanical & Electrical Systems. There is a three or four page discussion about this very subject. Then decide if you want to buy the book, which, for a boat the size of yours, should be required reading. Good luck.

 

[spraygun]

Here is a choice of books to read.You might find one that works for you.

 

[Bill Roosa]

if there are other boats in the water nearby connected to the shore power you may not be the problem child on your section of the river. If they are leaking current from shore power and you ground to the same service provider you become the preferred ground. the other boat may not have a problem as his corrosion protection plan works under those conditions, just screws every body else in the pond. try measuring between the shore power ground lug on the boat and the ground hole at the dock. also the dock ground and the water to see what voltage you might have. should see 0.00 volts "or less"