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Old 11-17-2015, 02:08 AM   #1
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Default Anode help

New Magnesium "zincs" on my freshwater 3000SCR this year. Boat was in the water from the middle of July until the first week of November. The boat was last "used" on Labour Day weekend. We were anchored for the weekend with the outdrives up and clearly visible. The anodes were mint. Since then, the boat had been plugged in at the dock, not moving for two months. When the boat came out the anodes were completely flaked off. I know its not my boat and that stray currents abound with my boat's anodes eating it. I believe that some kind of isolator exists to help with this. Can someone point me in the right direction.

much thanks

Bush
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Old 11-17-2015, 02:46 AM   #2
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Search for a galvanic isolator. What makes you certain it's not your boats system? Was there any rewiring or connectors replaced on the dock recently?

There is a test anode that you use with a volt meter to measure stray currents.
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Old 11-17-2015, 02:51 AM   #3
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Even though the boat is 17 years old it's in mint condition. Always freshwater, always heated indoor winter storage. That's why I'm pretty sure it's not the boat. There could have been something at the dock. It is a large Marina. How complicated is the install for an isolator?

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Old 11-17-2015, 02:37 PM   #4
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It may not be your boat. It might be stray current at the marina. Until you find it, make a point to change zinc's mid season.
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Old 11-17-2015, 04:07 PM   #5
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"How complicated is the install for an isolator?"

See the links in the link below for details but it is straight forward.


PROFESSIONAL MARINER ProSafe FS Galvanic Isolators | West Marine
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Old 11-17-2015, 09:04 PM   #6
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If your in fresh water I would use zinc or aluminum anodes. Magnesium are for brackish water.

Also if you have aluminum pontoon boats nearby in your marina that could cause wear and tear on your anodes.

Ask your marina owner when the last time he checked leakage on the shore power towers?

Good luck

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Old 11-17-2015, 10:40 PM   #7
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Default Anode help

All 30+ power and sail on my end of the dock. Looks like I have some winter homework. Luckily the heated warehouse is a convenient place to work.
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Old 11-17-2015, 11:38 PM   #8
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Quote:
Originally Posted by biggerseagar View Post
If your in fresh water I would use zinc or aluminum anodes. Magnesium are for brackish water.

Also if you have aluminum pontoon boats nearby in your marina that could cause wear and tear on your anodes.

Ask your marina owner when the last time he checked leakage on the shore power towers?

Good luck

Roger
Roger you got it backwards. Zinc or aluminum for salt water, aluminum for brackish, and magnesium for freshwater.

Seems that something changed near you since half way through the season with minimum wear then aggressive wear since. Did you talk with nearby slip holders to see if they had the same occurrance?
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Old 11-17-2015, 11:46 PM   #9
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Well, define flaked... Like, there was nothing but a flake left, or there was just a layer flaking off?
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Old 11-18-2015, 12:46 AM   #10
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They are done. I can flake it all off.
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Old 11-22-2015, 02:34 AM   #11
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I agree with Mike - mag for fresh. Aluminum, and especially zinc, are more noble than magnesium. The magnesium decays so that your aluminum stern drive doesn't.
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Old 11-22-2015, 03:51 AM   #12
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I'm aware of magnesium for freshwater. My concern was that they went from 100% to zero in two months at dock. Consensus is that there is stray current at the dock.
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Old 11-22-2015, 01:59 PM   #13
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One hell of a current!
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Old 11-22-2015, 02:34 PM   #14
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Well whatever ever you do inform the marina of your problems and no swimming in that water until something is resolved.

Roger
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