Galvanic Corrosion/zinc depletion question.

Nov 6, 2020
554
Mariner 36 California
It really helps to know if you’re causing your own zinc corrosion. I bought the tester as well, and once I was pleased that my boat wasn’t generating the erosion of my zinc’s. I started checking near other boats, and though I could not discover the source, it really became obvious when the Boat nearby moved away.
I wish i had the room for an isolation transformer. They are not terribly expensive, just so little space left on a 36 ft boat after all the essentials are in.
 
  • Like
Likes: jssailem
Nov 6, 2020
554
Mariner 36 California
It really helps to know if you’re causing your own zinc corrosion. I bought the tester as well, and once I was pleased that my boat wasn’t generating the erosion of my zinc’s. I started checking near other boats, and though I could not discover the source, it really became obvious when the Boat nearby moved away.
Thanks. Yeah this is getting frustrating. Just got billed for another set of zincs this weekend. Thats about a two month interval. Re-tested everything with silver/silver chloride, and when all systems turned on, both sides DC and AC, my hull potential only drops by 10mV which is well within acceptable range. I tested yesterday when all three of my neighbors on my stbd side of boat were away with their boats. My neighbor on port has a giant catamaran was there though. Dive comapny says they are still using same brand of zincs. I guess i need to go down the rabbit hole fairly deep now to try and solve this.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
8,015
Hunter 430 Waveland, MS
Guessing from me...
Boats from non USA use 50 Hertz frequency versus 60 Hertz.

If one is nearby you...
Big Zinc loss

Jim...
 
  • Like
Likes: jssailem
Nov 6, 2020
554
Mariner 36 California
Guessing from me...
Boats from non USA use 50 Hertz frequency versus 60 Hertz.

If one is nearby you...
Big Zinc loss

Jim...
Interesting, thanks. Not that i know of. Typical Southern California marina filled with local boats. We have had a few new boats show up over the past few months on our dock, but most look to be typical locally wired boats.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
8,015
Hunter 430 Waveland, MS
Metal Hull boats, even 200 feet way, could be wired wrong too.

Too hard to describe how to use your Ag ref probe as a "Stray Current Detector" but it can be done.

I will check later.

Jim...
 
  • Like
Likes: jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,494
CAL 35 Cruiser #21 moored EVERETT WA
My diver tells me he gets a tingle when near a boat that is poorly grounded or leaking electricity into the surrounding waters. Tells me that metal commercial boats are the worst.
 
  • Like
Likes: JamesG161
May 17, 2004
6,136
Beneteau Oceanis 37 Havre de Grace
Guessing from me...
Boats from non USA use 50 Hertz frequency versus 60 Hertz.

If one is nearby you...
Big Zinc loss

Jim...
I don’t see why having a 50hz designed boat receive 60hz would have any impact on zinc loss. Many appliances are designed to work with both. The ones that aren’t might have some issues, but that won’t affect the circuitry of the boat or the path electricity takes to ground. The AC system should be connected to the ground system in only one place on the boat - at the ground point. The AC neutral should only be connected to ground at the shore pedestal. Nothing about how many times per second the AC current oscillates affect the paths the current takes in this configuration.
 
May 17, 2004
6,136
Beneteau Oceanis 37 Havre de Grace
My diver tells me he gets a tingle when near a boat that is poorly grounded or leaking electricity into the surrounding waters. Tells me that metal commercial boats are the worst.
And that’s why diving or swimming near boats in fresh water is not recommended - In salt water the current has a pretty conductive medium to go through, so only enough gets through the diver’s body for a tingle. In fresh water with the same fault the water can’t carry the electricity, so the human carries it all, sometimes with tragic effects.
 

colemj

.
Jul 13, 2004
1,048
Dolphin Catamaran Dolphin 460 Mystic, CT
50Hz vs 60Hz makes no difference. As stated, AC current has little impact on stray current corrosion. If the culprit does happen to be AC current, then the specific frequency plays no part in it.

Mark