Delaware River Anodes

joedee983

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Jul 3, 2010
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I boat mostly in the Delaware, from Trenton to near the Phila airport, I keep the boat at Neshaminy marina for the season.
I currently have aluminum anodes on the sterndrive. I noticed that there is no wear on the anodes.
Is aluminum the correct material? Should I be using Zinc or Magnesium?

Thanks
 

Frank Acampora

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Jan 19, 2007
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Well, first off, since the outdrive or outboard is aluminum, there is no potential difference between the outdrive base metal and the anode. Aluminum is not the best choice, zinc is better.

Second, up by Neshaminy, the water is not brackish--it is basically sweet so any anode you do have will not show much wear.
 

Thalasso

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Jan 18, 2011
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Well, first off, since the outdrive or outboard is aluminum, there is no potential difference between the outdrive base metal and the anode. Aluminum is not the best choice, zinc is better.

Second, up by Neshaminy, the water is not brackish--it is basically sweet so any anode you do have will not show much wear.

What is sweet water? Never heard that term
 

Mikeopsycho

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Feb 6, 2014
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You should be using magnesium anodes if you're mostly running and mooring in fresh water. In tidal rivers I believe the salt water is heavier than fresh water, so you'd essentially be moored in fresh. I'm not familiar with your area but based on Franks response you're in fresh water. I've never heard of aluminum anodes, and I wouldn't use them in any kind of water. Zink is more suited to salt water as an anode material.
 

dingbat

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Nov 20, 2001
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15,414
The "salt line" moves up and down the river based on tides and water flow. Currently, the salt line (as of 8/15) is is roughly 14 miles south of the airport but has been as far up river as the Ben Franklin bridge in the past.

Pollution can be as hard, if not harder on dissimilar metals. Combine the two, zinc is the only way to fly ;)
 
Last edited:

lg260ss

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Jun 25, 2011
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Both Volvo penta and Mercruiser recommend the following:
Fresh water- Magnesium
Brackish Water- Aluminum
Salt water- Zinc

All new outdrives come standard with aluminum anodes. It is the customers responsibility to use the correct anode.
 

pole position

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Dec 14, 2008
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156
Both Volvo penta and Mercruiser recommend the following:
Fresh water- Magnesium
Brackish Water- Aluminum
Salt water- Zinc

All new outdrives come standard with aluminum anodes. It is the customers responsibility to use the correct anode.

As a fellow river rat,I would use magnesium anodes.I have inboards and my zincs last 2-3 years.I have never seen mag ones for inboards.
 

four winns 214

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Oct 25, 2008
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Another voice for magnesium. If you change to magnesium, you'll see them decay (wear) for certain.
 

joedee983

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Jul 3, 2010
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Thanks everyone, I think I'll try the magnesium and hang on to the aluminum in case I decide to go further south.
 
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