Question - Engine Anode

Hi All,
Last season Soave’s hull and shaft anodes depleted faster than normal.

For this season, I added a galvanic isolator and a second shaft anode.

Last week, I got to thinking I ought to check my engine anode which protects our heat exchanger.

( HERE ) is photo of the anode that I removed for inspection. It’s not as badly depleted as the shaft and hull anodes but still ought to be replaced for the 2025 season.

Questions :

  1. How often do others generally inspect or replace engine anodes ?
  2. Which style do you use the zinc only type or the “pro” type where the zinc is fused to the brass fitting ?
  3. Does the wear on my anode look normal for two seasons ?
    Thanks,

Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT

We have the 5432 engine in our boat.
1: I replace the heat exchanger anode every year. I used to check every month but that proved to be not required.
2: I use the anodes that screw into a brass fitting.
3: That level of wear is about what I would expect after 2 years.

Blake
N33
Brentwood Bay BC

I normally replace mine brass fitting style about once a year. Yours doesn’t look very bad the the amount of time you mentioned.

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

Rob, I check my heat exchanger anode every 1-2 months, and note it in my logbook. And replace it every 6-8 months. It only takes a few minutes, and replacing an anode is significantly cheaper than a heat exchanger. I had to replace my heat exchanger because I suspect the PO didn’t check it often enough and it developed some pin holes in the metal that then weeped salt water on the engine. This in turn creates rusting of engine parts below heat exchanger and engine mount. When checking the anode I put a plastic take-out food container under the heat exchanger to catch the salt water. I wrap my left hand around the back of the heat exchanger so I can plug the hole quickly with my finger while removing zinc with my right hand. I only use regular zinc, haven’t heard of the Pro type.

Also, where I’m from, it’s common practice to put two zincs on the propeller shaft. Zincs are much cheaper than propellers. Your boat’s electrolysis and zinc wear may also be affected by neighbouring boats in the marina.

Cheers :sailboat:

Thanks Don, Joe, and Blake… for confirming my thinking about the engine anode. It’s easy to check ( especially if the fitting is kept from corroding ).

I’ll keep a closer eye on it going forward and always have some extra anodes in my parts inventory.

I think it’s worth noting that the 73 page New Nonsuch Owners “Quick Guide”. Doesn’t mention anodes… and it took me ( a 30 year dingy racer ) about a year to hit my stride on maintenance for Soave. The challenge is rewarding.

Next round of questions will be about fuel systems, as I just experienced my first clogged fuel filter.

Thanks,

Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT

Summary of the discussion about engine anodes.

  1. Most owners check their engine anode a couple times a season.
  2. Generally engine anodes last one or two seasons… or more.
  3. The screw on replacements are inexpensive ( about $ 2 each ) so it kinda makes sense to throw a new one in if the old one is partially depleted.
  4. There are two styes. A “Pro” style that boasts that the zinc is bonded to the brass fitting and therefore less likely to break off when removing. They cost about $9 each. The standard stye didn’t give me any problems, except that when I unscrewed the brass fitting from the heat-exchanger the zinc also unscrewed luckily not all the way so I was able to withdraw the zinc. This is a good reason for frequent inspections, to avoid having to deal with badly depleted anodes getting loose.
  5. (HERE) is photo showing both styles and the old anode. I sourced them via boatzincs.com. I bought enough to have spares and to qualify for free shipping… so I’m set for the next few seasons. I think I prefer the old style.
    • E-0Z Engine Zinc Anode (Zinc Only)
    • E-0 PRO Engine Zinc Anode - 1/4 NPT x 1-3/4"
  6. Have something handy to catch the saltwater that will drip out and have your tools and replacements within reach because you will need one finger to close the hole while you are inspecting /replacing the anode.
  7. This is preventative maintenance that is cheap and easy to do and helps avoid bigger more expensive things down the road.
    Many thanks to the participants in this tread.

Rob Cohen
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT

.

The electrical system in my marina is not good. Even with a a galvanic isolator the pencil zincs in the heat exchanger only last about 3 months. They are small only 1/4” x 1 1/2”. I use two zincs on the prop shaft and the prop has its own zinc.
I do have parasitic loss of .2 amps that I need to track down. Because of that and winter heating the shore power is always plug in.

Mark Powers

If you install an ELCI it should help you find the leak.

Two on the shaft,one on the strut and one on the engine.. I get a year and have an isolator installed. We plug in only over the winter so it will be interesting to see how much it changes. I use aluminum anodes not zinc