Change Anodes from Salt to Fresh Water?

If you are going to do the loop, do you need to change your anodes from zinc to something else when you move from salt to fresh water?

No.

Anode wrote:
No.

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*And with a name like Anode, who could disagree on a point relating to, well, anodes?

While in fresh water the zinc will not work.

Magnesium is the anode choice in FW.

For a few months , most folks get away with it.

Thanks for the info!

FF wrote:
While in fresh water the zinc will not work.

Magnesium is the anode choice in FW.

For a few months , most folks get away with it.

Click to expand...

*What if you routinely fresh water flush the engines after running in salt water???

I was under the impression that the magnesium anode was mainly needed in fresh water for aluminum as in an outdrive, and was not necessary to protect stainless or bronze as in a typical inboard.

*Maybe I'd better go back and read da book?

*

*

Magnesium is the best anode for fresh water ...IF...you are never in salt water and NEVER mix them with zinc anodes.
Zinc anodes work well in fresh and salt water.
The question was should you change anodes when transitioning in and our salt, brackish and fresh water doing the loop. My answer is still no. It's not worth the time and cost. If you have properly installed zinc anodes they will work fine in fresh water for doing the loop. It's all I use and they work fine for me.
Aluminum boats are a different beast and additional cathodic protection is generally necessary.

Unfortunately the answer isn't simple. Zinc anodes will not work in fresh water, Many will tell you they have no problem with zinc in fresh water and that is because they don't do anything. For fresh water you want to use magnesium anodes, but don't use them in salt water. Aluminum anodes are for salt or brackish water but not for fresh water. I suspect many loopers don't change the anodes and leave them for whatever water they will be boating in at the end of the loop. But be aware that you might not be protected. Chuck

Capn Chuck wrote:
Unfortunately the answer isn't simple...... For fresh water you want to use magnesium anodes, but don't use them in salt water.

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* * * ** I heard this years ago from an "old salt."

Are you calling me old or salty?

timjet wrote:
*

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*What if you routinely fresh water flush the engines after running in salt water???

*Works fine for the pencil zincs in the engine.

*Doesn't help with the rest of your underwater metal.

SD


-- Edited by skipperdude on Wednesday 29th of June 2011 12:26:57 PM

Old Goat wrote:
If you are going to do the loop, do you need to change your anodes from zinc to something else when you move from salt to fresh water?

Click to expand...

*Ahoy Old Goat!
Due to considerable research I've accomplished (and am still accomplishing) - I hope this helps. - Cheers,*Art*
Anode protection is surely a necessary, yet a*difficult item to feel confident about which anode material is best in fresh water or in transition from salt to fresh... regarding*various hull and equipment materials:
That said I believe there is no need to change from zinc when in fresh water, under certain maintenance conditions.
2.4 years ago, with all locations on boat having new zincs installed just before we left SF Bay salt water, I began keeping our fiberglass Tollycraft tri cabin, twin screw with through hull shafts*in the*fresh water that is always present deep into SF Bay Deltas 1,100 miles of levee lined rivers and channels.* I had been informed that my zinc anodes would protect just fine as long as I consistently wire brush the surface build-up that forms in fresh water off them.* As the water is warm for swimming most of the year, and*I love to swim/dive with fins and mask, I greatly enjoy the fun-task of often keeping the zinc surfaces brushed clean.* I feel the often-cleaned zinc is doing a good job (cleaning once a month in spring, summer, and fall; with a span of several months during winter).* There is NO galvanization occurring on SS shafts and trim tabs or the, Bronze props, struts, rudders and through-hulls... I inspect it all very carefully with bright flashlight during each cleaning.* It appears that after this 2.4 year fresh water duration the zincs still have 50% +/- remaining material.* I plan to install new next spring... under current conditions.* Due to my concern re anodes in fresh water I researched many anode reviews, and listened closely to real-life-experience from boat owners.*
Ive come to this conclusion (for boats equipped like mine):
1.***** Zinc is absolute best anode for salt water (I already knew that from years of past experience)
2.***** Zinc is fine in fresh water as long as you can often wire brush the film that develops off the surfaces it lasts a long time too BUT... zinc surfaces must be brushed clean on a regular basis or the formed coating will eventually make the zinc inoperable
3.***** Magnesium is good to use in fresh water and evidently brushing its surface clean is not needed BUT... evidently mag will not last anywhere near as long as zinc (I havent tried Mag yet in fresh water, so I'm not in firsthand knowledge of its efficiency or duration of last ability.* I may try mag upon next anode change, but have found that unlike zinc, mag is not easily located in configurations that apply to all under hull apparatus)
That said; here are a couple anode items from experts that I feel tells it like it is!
Hi Art,
Good to speak with you. I think you should be fine w/the amount of cleaning maintenance that you perform on zinc.* Your friends with the steel pontoons and Aluminum outdrive should consider using magnesium anodes. Not sure if they have a kit from Mercury, but it can be found on the net.
*
Here is a quick galvanic series table showing potentials/levels of metals.* Have fun up there in SF Delta!
*
Most Active (least noble) Anodes from top down with Least Active (most noble) Cathodes from bottom up:
*
Magnesium
Zinc
Aluminum (2S)
Cadmium
Aluminum (175T)
Steel or Iron
Cast Iron
Lead Tin solder
Lead
Nickel
Brass
Copper
Bronze
Stainless Steel (304)
Monel Metal
Stainless Steel (316)
Silver
Graphite
Gold
*
Regards, Harry Coulombe
Marine Division/Technical Sales / Farwest Corrosion Control Company
1480 W. Artesia Blvd. / Gardena, CA 90248
310-532-9524 X. 1116 main / 310-770-0652 mobile / 310-532-3934 facsimile
hcoulombe@farwestcorrosion.com **/ www.farwestcorrosion.com

*
I feel the following is a good report - Art
*
The Role of the Sacrificial Anode
*http://gulffishing.com/tips_anode.html
*
By: Martin Wigg and Paul Fleury
*
Martin Wigg is president and founder of Performance Metals.* He holds an MBA and Bachelor of Science degree in mechanical engineering.* Paul Fleury is certified by American Boat and Yacht Council as an Electrical Technician and the National Association of Corrosion Engineers as a Corrosion Technologist




-- Edited by Art on Thursday 21st of July 2011 10:01:54 AM



-- Edited by Art on Thursday 21st of July 2011 10:16:12 AM


-- Edited by Art on Thursday 21st of July 2011 10:21:15 AM