Anodes, aluminum, zinc, magnesium?

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kpinnn

Senior Member
Joined
Jun 25, 2012
Messages
137
Location
USA
Vessel Name
Periwinkle
Vessel Make
Gulfstar 36
Ok, we sail the Periwinkle from fresh water to salt water for the summer and then back to salt. Consequently I want to use aluminum anodes due to the coating that is produced on zinc anodes with this type of operation. I also know the all need to be the same. But, what about engine anodes and the plate located on bottom of vessel? Is it an anode? It shows no degeneration. Is that a zinc anode that isn't working or a ground. If it is an anode can I get it in aluminum? If so where?
 
We're 100% Aluminum now. We go from brackish to salt plus this year Hobo also spent time in fresh water. We have a 5" circular anode on the rudder, an anode on the prop, a plate anode on the transom plus a pencil anode in the heat exchanger. I have been told that your boat should have all the same. I think someone recently posted that the type you use in the heat exchanger can be different since that is not typically tied in to the bonding system. We went all the same since they are available.

We buy everything from Boatzincs.com except the pencil anode which we by from Performace Metals.

BoatZincs.com (978-841-9978) - The Online Superstore for Zinc Anodes

Rudder Trim Tab Anodes
 
A couple of years ago when aluminum anodes start there was a discussion, that alluminum was more protective than zinc. When talk working with metal its the galvanic rating that is important. The lower the rating the more it protect metal of higher rating. So zinc usually protect aluminum, and aluminum protect mild steel. So before you switch make sure you know and compare the galvanic rating. I heard they where going to stop making zinc, so I bought 2 sets of true zincs which should last another 6 years. I am not a believer yet.:blush:
 
I believe SidePower thrusters have gone 100% to Alum anodes.
They state there is no problem when mixing w/ other mat'ls for boat anodes because the thrusters are isolated.

I read the same about all anodes being the same - when I moved my boat I went 100% w/ alum including engine / gen anodes.
Note the Alum anodes are not 100% Alum they are an alloy w/ small amts of other metals and claim to protect alum components.
 
Ok, we sail the Periwinkle from fresh water to salt water for the summer and then back to salt. Consequently I want to use aluminum anodes due to the coating that is produced on zinc anodes with this type of operation. I also know the all need to be the same. But, what about engine anodes and the plate located on bottom of vessel? Is it an anode? It shows no degeneration. Is that a zinc anode that isn't working or a ground.[/COLOR] If it is an anode can I get it in aluminum? If so where?

Are you by chance talking about a sintered bronze grounding plate for an SSB radio or lightning protection? We have 2 plates on the hull that I struggled to identify until the yard manager told me what they were and why they look different than the aluminum anodes.
 
Try this

Whatever happened to fstbttms anyway?
 

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From Everett marine and my diesel mechanic. I don't know the reason. Old school is zinc for salt and brackish, magnesium for fresh. Being aluminum rate is 10+ it has to be a high% of magnesium. I am not a believe. Also aluminum has been used instead if zinc in some toxic application.
 
I should add that on our Loop boat, once we get it to the TN River or perhaps even on Lake Michigan, we will switch to Magnesium since it will remain in fresh water a couple of years.
 
I have 14 aluminum anodes on my boat and 2 left-over zincs. I am on the hard now and all except the two zincs were changed. The aluminum work great and they last longer, supposed to be cheaper but haven't seen the bill yet.
 
We're in brackish and salt. I'm going all aluminum this year. I found the aluminum anodes to be just about the same price as zinc.

Ken
 
Greetings,
Mr. fst. I don't think anyone was trying to get rid of you. Just wondering when you would come up for air...

h9D81261B
 
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