Anodes for SF Bay and CA Delta

First off all, Happy Thanksgiving!

Wondering for those who move between the San Francisco Bay and the Delta, what type of anodes do you use?

Thanks,
Mike

Thanks fstbttms, yeah, I definitely did my research and was trying to determine whether to go with zinc or aluminum. The boat would mainly be in the Bay and in Alameda at the marina, with occasional trips on the Delta. Wasn't sure if occasional Delta trips made aluminum a better option or not. I saw on one site that it would take about a month for the white residue to form on zinc in brackish water, which suggests that zinc is fine for my use. However, it also seems that aluminum has no downside. So was just wondering what others that use their boats in both the Bay and Delta were using.

Thanks,
Mike

Well, magnesium is definitely out, since your boat spends most of it's time in saltwater. My professional suggestion would be to go with aluminum.

Well, there is a downside. If you use an aluminum anode in salt water you don't get as much protection as zinc. The Bay is almost the same salinity as sea water, right?

David

djmarchand said:

Well, there is a downside. If you use an aluminum anode in salt water you don't get as much protection as zinc.

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Please elaborate.

djmarchand said:

The Bay is almost the same salinity as sea water, right?

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Yes.

From the research I've done, seems like there is a negligible performance difference in salt water between aluminum and zinc. However, if you go into fresh water and the zincs are compromised then you go back to salt, they are going to perform far worse than aluminum. Seems like aluminum is the best bet for Bay and Delta usage, at least on paper. But again, wanted to know what people are doing in practice in the area.

My assumption is that many are still using zinc out of habit.

Is there a difference in lifespan between zinc and aluminum in salt water? Or are there too many variables for a reliable answer?

BruceK said:

Is there a difference in lifespan between zinc and aluminum in salt water? Or are there too many variables for a reliable answer?

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I'm not an expert by any stretch, but the vast majority of credible resources seem to indicate that Aluminum lasts Amor 15% to 20% longer in salt water.

Here's an interesting article that elaborates on the differences in terms of voltage, life and density.

http://www.performancemetals.com/images/pdfs/Aluminum Anodes.pdf

We switched to aluminum anodes 3 years ago. Our travels take us from fresh to salt and back again several time each year. In saltwater, aluminum actually provides a slight favorable -500 millivolt shift relative to Zinc. Aluminum gives better protection in saltwater. Plus, as others have said it can be exposed to salt, fresh and every combination of brackish water, and continue to work. Zincs develop an oxide film if they are in freshwater. Once they are back in salt water, the protection is reduced or even stopped.

BandB said:

Here's an interesting article that elaborates on the differences in terms of voltage, life and density.

http://www.performancemetals.com/images/pdfs/Aluminum Anodes.pdf

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Hey -Thanks B!! Read the entire anode-link review you provided. Very informative and to the point.

I today [Saturday of Thanksgiving weekend] emailed Performance Metals regarding list of Aluminum anodes our boat requires and received comprehensive email response in short order on this same day.

Wow... I call that Great Service! I will place a full order next week. MOF, I plan to order two complete sets of their Aluminum anodes... to be sure I've the next set already aboard.

Another informative page: http://www.performancemetals.com/anodes/AnodeFAQs.shtml

Is there a better website for buying zincs than boatzinc.com? Their prices look pretty good compared to others I've researched and shipping is free on orders over $100.

I have no financial interest in boatzinc.com, just looking for the best deal on quality, Mil-spec'd zincs.

FlyWright said:

Is there a better website for buying zincs than boatzinc.com? Their prices look pretty good compared to others I've researched and shipping is free on orders over $100.

I have no financial interest in boatzinc.com, just looking for the best deal on quality, Mil-spec'd zincs.

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For the cost in general... service is paramount - IMO


I'm not at all saying that boatzinc isn't a great service organization.