Mixing anodes from different manufacturers

Hi all, does anyone see an issue with mixing aluminum anodes from two different sources? One is Martyr, and the other Boatzincs.com. Both say their anodes adhere to MIL-A-24779(SH) spec. Although Martyr says their anodes do not contain cadmium, while I don't see any such claim from Boatzincs.com.

Lastly, I noticed that Boatzincs.com only has a zinc version of the No. 15 Transom Anode. Anyone familiar with Boatzincs.com site know what aluminum anode might work in place of the No. 15 Zinc?

Or if my boat has the No. 15 now, do I even need to stick to that type?

Sorry, newbie on this stuff!

Thanks!
Mike

MichaelB1969 said:

Hi all, does anyone see an issue with mixing aluminum anodes from two different sources? One is Martyr, and the other Boatzincs.com. Both say their anodes adhere to MIL-A-24779(SH) spec. Although Martyr says their anodes do not contain cadmium, while I don't see any such claim from Boatzincs.com.

Lastly, I noticed that Boatzincs.com only has a zinc version of the No. 15 Transom Anode. Anyone familiar with Boatzincs.com site know what aluminum anode might work in place of the No. 15 Zinc?

Or if my boat has the No. 15 now, do I even need to stick to that type?

Sorry, newbie on this stuff!

Thanks!
Mike

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Boatzincs often had anodes available that are not represented on their web site. I would speak directly to them.

BandB said:

Boatzincs often had anodes available that are not represented on their web site. I would speak directly to them.

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Thanks for the tip, I just sent them an email.

Anodes are not like batteries. You can mix manufacturers with no problems.

The Boatzincs site shows that the N15 zinc anode has a 3.1" center to center dimension for the two holes. Several aluminum anodes have 2-7/8" center to center dimensions that could easily be enlarged to fit and a couple are slotted that would work with no modifications, like the Mini Diver's Dream. So pick the one that fits with your available outside room.

Davod

Mike

No need to be exactly the same shape...
I've gone to buying Al plates and drilling them myself for the hull anode.

If I have the correct #15 it's 6" x 2.4" If you have room around it consider a 6" x 3" AL plate and use the old one as a template top drill the holes

3" x 6" Alum

or as David suggests you might consider Mini Divers Dream Aluminum Anode if you have the 4" space

or AZHC-3 spacing slightly less but they are slotted and may fit

MichaelB1969 said:

Hi all, does anyone see an issue with mixing aluminum anodes from two different sources?

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Wow, are you overthinking this.

fstbttms said:

Wow, are you overthinking this.

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Well, it is my first boat, and it wasn't cheap. And I don't know what the hell I'm doing. So I'd rather waste a little time and energy and overthink it than not thinking about it enough and running into costly issues down the line.

With the mixing of metals, I know it's bad news to mix types, like Zinc and Aluminum. So that being the case, I read that some of the aluminum had cadmium, some didn't. Some were made of a mix of metals like the Navalloy. So just being cautious.

Anyways, thanks for the help, and thanks for the reply to the email I sent you. When my boat needs its first bottom cleaning, I will give you a ring.

Best,
Mike

Thanks BandB, they did have some of the other parts in stock, and they were able to special order the others.

And thanks djmarchand and Bacchus, I ordered some of the alternatives you referenced.

This community is great. Very appreciative of all the help and guidance.

MichaelB1969 said:

Thanks BandB, they did have some of the other parts in stock, and they were able to special order the others.

And thanks djmarchand and Bacchus, I ordered some of the alternatives you referenced.

This community is great. Very appreciative of all the help and guidance.

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Glad it worked out for you. They normally can take care of any needs.

Bacchus said:

Mike

No need to be exactly the same shape...
I've gone to buying Al plates and drilling them myself for the hull anode.


or AZHC-3 spacing slightly less but they are slotted and may fit

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OK.... how did you do that? Did the anode have tabs? Drilling the aluminum alloy itself for mounting bolts won't work because the material under the bonding bolt will disappear as the anode does it job.

I purchased an aluminum hull anode similar to a Diver's Dream or whatever it is called from West Marine last fall. Mine is 6" x 12" x 1" for installation this spring. West has them in their catalog.

foggysail said:

OK.... how did you do that? Did the anode have tabs? Drilling the aluminum alloy itself for mounting bolts won't work because the material under the bonding bolt will disappear as the anode does it job.

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Most anodes do not have metal inserts cast into them to keep fasteners attached. They all seem to work fine.

Here is my order from Boat Zincs .com that I received today. All in aluminum.


Item # Description Qty
X-9AL Martyr X-9AL Shaft Aluminum Anode - 2" 4
R-3HA R-3HA Rudder Aluminum Anode - 4" Dia. Heavy 2
DP-612A DP-612A Aluminum Anode 1

The DP-613 is the plate for the stern. You should be able to look these up on their website.

fstbttms said:

Most anodes do not have metal inserts cast into them to keep fasteners attached. They all seem to work fine.

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Well----- that was a surprise but sure enough, hunks of anode metal are available. I would think those with an interior steel plate provided better electrical connection to the bonding circuit. Thanks for pointing that out.

When I remove my hull plate at season's end, most of the anode material is gone but the interior metal plate remains firmly attached. For that reason I doubled the thickness from 1/2" to 1" for next season. I use only one aluminum plate anode for galvanic protection.

foggysail said:

OK.... how did you do that? Did the anode have tabs? Drilling the aluminum alloy itself for mounting bolts won't work because the material under the bonding bolt will disappear as the anode does it job.

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A little nail polish around the hole will slow the erosion at the attachment. Similar to protecting the attachment area on shaft anodes to extend life.
A small dia washer w paint under would probably be even better.
Best practice to check continuity after mounting to be sure you have contact at some point.

Bacchus said:

A little nail polish around the hole will slow the erosion at the attachment. Similar to protecting the attachment area on shaft anodes to extend life.
A small dia washer w paint under would probably be even better.
Best practice to check continuity after mounting to be sure you have contact at some point.

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Thanks Don, but I plan to stay with anodes that provide an internal plate to ensure good bonding. Consider the many anodes commercially used for bonding bulkheads for example. Those provide interior metal plates for welding the anode to a bulkhead. I see that style predominantly used on metal hulls of our local fishing boats.

I also check every season the efficacy of my anode using my silver-silver chloride half cell. I believe this is the best anode performance test for galvanic protection.