anode question

[batate]

We just bought a 2014 and there are new zincs all around... for salt water. We're going to have the boat in fresh water for 3 months, before starting our loop and getting to Mobile around Feb 1. I would prefer not to take the boat out of the water to get new zincs all around, only to replace them when I get to Mobile.

Question 1. How much damage am I doing by using salt water zincs in fresh water for 3 months?
Is there anything I can do short of pulling the boat or getting a diver to add a whole round of freshwater zincs for just 3 months?

Question 2: How much will a galvanic isolator help?

Question 3: Is there a temporary solution like an anode chain/weight that I could ground? How would I do that?

All opinions on this issue would be most welcome.

Thanks!
- Bruce and Maggie Tate, Currently

 

[aintmissb]

I am curious about these exact same questions. I used to own a C28 which I moved from salt water to fresh and didn’t touch the zincs. I now own a new boat built for salt water but currently on the freshwater Lake Ontario. But it was only in the water for 4 months, now in heated indoor storage. Would appreciate any input regarding the zincs.

 

[Alpina]

Replace with aluminum which can be used in both salt and fresh water. Zincs won’t work in fresh. The galvanic isolator helps stray current issues from other boats in the marina. Having that will lessen the anode corrosion if you have the stray current situation as the cause but solve the zinc in freshwater issue.

boatzincs.com should have everything that you need.

As an aside, if you keep solely in fresh, get magnesium anodes if you can find for your application. I have mostly magnesium on my boat with aluminum where magnesium wasn’t available but I only boat in fresh water.

Sent from my iPhone using Tapatalk

 

[BB marine]

A galvanic isolator will help save your anodes if you are tied in a slip and plugged in to shore power.

The Zinc anodes do little or nothing in fresh water. A zinc anode in a short period of time will because they build up a hard, dense coating over a period of months – rendering the anode ineffective inprotecting the metals it is installed to protect.

Aluminum alloy anodes will work in fresh water, brackish and salt water. I used aluminum alloy anodes for 5 years on the C26 and had very good success and comparing to a few of my Ranger and Cutwater friends that used zinc anode in salt water I saw better performance with the Aluminum.

Below is a picture of my Aluminum anodes that were installed in May of 2020 Lake Michigan for 3 months, then Kentucky lake to the Florida panhandle 3 months, then South West Florida to the keys and then the east coast of Florida and back to Ft Myers 3 months of salt water. I replaced the Aluminum anodes in May of 2021 and they where eroded less than 20%.
gallery2.php?g2_itemId=81355

I would install all new aluminum anodes now and forget about doing them in Mobile you will be good for the Loop. I would obviously check them monthly but I could have easily done the complete loop with the anodes installed on my boat.

 

[Diver]

It's interesting that the engine manufactures (or aftermarket) have not caught up in making available aluminum or magnesium anodes. Can't find any for my Yanmar or Mase genset. According to BoatZincs It's OK to use the zincs on active engine internals in combination with aluminum or magnesium externals. I still would feel better If I had all the same.

 

[pwensinger]

All above is good advice. The U.S. Navy (since they operate exclusively in salt water) put zinc anodes on the WW2 submarine USS Cod then gave her to a group which moored her on the Cleveland waterfront. 70 years later, the Cod was drydocked and large electrolysis holes in her hull were repaired. A retired marine diver, who does volunteer work with the Cod, videoed the damage and the virtually new looking but 70 year old zinc anodes. Search for USS Cod on U-tube.

 

[Rocky Lou]

I've also become a fan of aluminum anodes even though I'm only in salt water. They seem to last just as well and are cheaper. I haven't heard any good reasons not to use them, except some like the outboard trim tab anodes, I can't find in aluminum.

 

[batate]

Many thanks, all. I guess aluminum it is. I like the idea of one anode for the whole loop.