R23Trim Tab underwater lights

I have a 2019 R23 (2nd owner), with I believe, were factory installed underwater trim tab lights. I have my boat at a slip plugged into shore power for 2 summers (20&21) in Long Island Sound NY(salt water) . Both times when winter hauled- the Yamaha 200hp trim tab anode was totally gone (only bolt remained) and the anode at the bottom of the engine mount was 50% gone. Luckily I didn't any electrolysis corrosion on any of hull metal. A friend of mine mentioned that possibly trim tab lights had something to with all the electrolysis activity. I rarely use these lights and if so only for short periods while under shore power. Any thoughts are appreciated.
I was also thinking about getting the $129. BoatZincs.com " Corrosion reference electrode & user guide" to help explore this activity further. Any thoughts on success/use of this item would be appreciated also.

I have nothing to add, but want to follow this thread too. Our new-to-us 2018 R23 also has the engine trim tab anode nearly gone and the transom anode much deteriorated as well. New anodes arrive today, but would like to know if there is anything in particular that causes them to get used up so fast (I have read other posts on here from R23 owners with similar reports).

I know Martin (@Submariner) just bought a tool that allows you to monitor the electrolysis some how - more info here: gallery2.php?g2_itemId=81401 - maybe something like that would be useful for you?

Hello Nickc,

What I would suggest to do is maybe adding a Galvanic Isolator to your system. This is the device I would use too, check out this link here: https://www.promariner.com/en/products/ ... s%20series

I would also add some bonding bolts and cables to the trim tab plates so when you add the isolator you will be bonded to the whole system and be able to use this device for what is design to do. Now what I can also add here is to replace zincs maybe sooner (like every 6-9 months) this is if you don't add the isolator, some marinas are really hot so the time to replace zincs might vary. I have seen marinas where you need to replaced anodes every 2 months so every year like your case doesn't seem too odd but again I will add a little more protection like I mention above here.

Thank you,

You are trimming your engine up, out of the water when at the dock, correct?


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I finally got around to having the hull cleaned on my R27OB, it was put in the water in the SF Bay area last January. Thankfully, the hull was fairly clean, and my zincs (according to the diver) are still 70-80% available. I don't connect to shore power (the two solar panels do a great job!) and I do have a galvanic isolator. The R27OB also has trim tab lights, but they aren't turned on...

Nickc":3bts5z66 said:

I was also thinking about getting the $129. BoatZincs.com " Corrosion reference electrode & user guide" to help explore this activity further. Any thoughts on success/use of this item would be appreciated also.

Click to expand...

briandunnington":3bts5z66 said:

I know Martin (@Submariner) just bought a tool that allows you to monitor the electrolysis some how - more info here: gallery2.php?g2_itemId=81401 - maybe something like that would be useful for you?

Click to expand...

I bought that Corrosion Reference electrode from Boat Zincs dot com. Not that I have a problem today, but I want to keep track of my baseline. Should my galvanic isolator fail, I'd like to be able to know. I also figured it's a good tool to have on the boat for others to borrow and test their own boat.

What this tool does it, it hangs an electrode off the back of the boat in the water. Run that through your volt meter with the other end connected to the DC ground/bonding system on the boat. It then gives you a voltage reading (your boats hull potential). -950mV to -1100mV is where I need to be. My reading, with the engine up/out of the water, was -1059mV.

If the reading is below (meaning, it's more positive), would indicate the underwater metals are under-protected and may be corroding. This may be resolved by simply cleaning the anodes or just replacing them. (I'd just replaced both my trim tab anodes, but not my transom anode).

If the reading is above (more negative), would indicate the underwater metals are over-protected and may be causing damage as well.

Thanks guys ..I appreciate all the responses. I am probably going with the boatzincs.com “corrosion electrode and user guide” noted first, then pick up a galvanic isolator to install later.
BTW my stainless trim tabs never had anodes so I installed them the other day (drilling 3/16 plate stainless quite a challenge.. until figured out a jig to get proper pressure on drill with a bad shoulder!). Hopefully this installation will help the problem.

Just checked my trim tab anodes on my 2019 R23 that is at my home dock and the anodes are almost gone. The Tug has not been plugged into shore power as I have relied on the solar to keep the batteries topped up. There is no shore power on dock. I am on a brackish creek a stones throw from the Great Peconic Bay on Long Island. I keep reading it’s the shore power but in this case I’m confused???
Jimmy
R23OB
Island of Long NY

Wenchris21":288a7wfu said:

Just checked my trim tab anodes on my 2019 R23 that is at my home dock and the anodes are almost gone. The Tug has not been plugged into shore power as I have relied on the solar to keep the batteries topped up. There is no shore power on dock. I am on a brackish creek a stones throw from the Great Peconic Bay on Long Island. I keep reading it’s the shore power but in this case I’m confused???
Jimmy
R23OB
Island of Long NY

Click to expand...

How long since you have replaced the trim tab anodes? If not since 2019 you are doing very good! The discussion about shore power is about excessive anode consumption above the level needed for your boat alone (not connected to shore power). Depending on the water conditions, 6 months to 1 year for trim tab anodes without shore power connection is normal. In brackish water 2 years seems about right/really good for total anode consumption. Shore power issues usually increase the consumption (reduce the life) from this normal level to as little a a few months. Having said this, if you are talking about the trim tabs on the boat and not the outboard trim anode the shore power connection will have no effect as the boat trim tabs are not bonded (and thus no connection to shore power) as delivered the factory. They will degrade solely based on water/oxygen condition.

I hope this helps.

Curt

Curt,
We have only had the tug since the spring so I cannot say when the anodes were last changed. I know on our Boston Whaler we get years from the anodes in the same water. Hauling the tug next weekend and I’ll be able check the other anodes then. In the meantime I’ll keep educating myself…..lots to learn.
Thanx Jimmy

This is what the anodes on our R23 looked like when we got it. Were these the original anodes from 2018? Were they just a few months old? No way to know BUT they have all been replaced with new ones so I can monitor how long they last going forward.

I did a Google search for "reasons why boat anodes corrode quickly in water". This is what it says.
When a boat's sacrificial anodes corrode unusually fast, it indicates that the cathodic protection system is carrying a heavier electrical load than intended. Anodes are designed to dissolve to protect your hull, propeller, and engine parts. However, rapid depletion (lasting only weeks or a few months instead of a full season) points to specific electrical or environmental issues. [1, 2, 3]

1. Shore Power Connections & Galvanic Bridging
When plugged into shore power at a marina, your boat’s safety ground wire connects your internal electrical system to the marina’s ground network and other nearby vessels. [1]

• • The "Bridge" Effect: If a neighboring boat has an electrical fault or lacks proper protection, your boat's anodes can end up acting as the sacrificial protection for their underwater metal components.
  • The Fix: Install a galvanic isolator in your shore-power earth path to block the low-voltage DC currents that drive this continuous corrosion. [1, 2, 3]

2. Stray Current Corrosion (Electrolysis)
Unlike passive galvanic corrosion, stray current corrosion is caused by actively escaping electricity. [1]

• • Faulty DC wiring on your boat (e.g., bilge pumps wired incorrectly, bad grounds, or cracked insulation) or damaged shore-power boxes can leak live current into the water.
  • This forces a massive electrical current through the anodes, causing them to melt away at an alarming rate. [1, 2, 3, 4]

3. Mismatched Anode Materials
Anodes must match the specific water chemistry they sit in. Using the wrong alloy causes highly accelerated depletion: [1, 2, 3]

• • Magnesium in Saltwater: Magnesium is highly active and designed only for pure freshwater. If a magnesium anode is submerged in saltwater or highly brackish water, it will aggressively dissolve within weeks. [1, 2, 3, 4]
  • Mixing Anode Types: If you install a mix of zinc, aluminum, and magnesium anodes on the same bonding circuit, the most active metal (magnesium) will overwork itself to protect the other anodes rather than just the boat, dissolving rapidly. [1]

4. Added Underwater Metal or Poor Hull Coatings
The anode's job is proportional to the amount of exposed raw metal it has to protect. [1]

• • If you have recently added new underwater hardware (like trim tabs, a new bronze propeller, or a transducer bracket), the existing anode mass may no longer be large enough, forcing the current anodes to burn out much faster. [1]
  • Similarly, if the protective paint or coating on your underwater gear has chipped or deteriorated, the anode has to work significantly harder to protect the newly exposed surface area. [1]

5. Water Temperature and High Salinity
The environmental conditions of your slip play a major role in electrical conductivity. Warm, highly saline waters (such as those in tropical climates) act as a much more efficient electrolyte than cold, northern, or brackish waters. Increased conductivity inherently accelerates the galvanic chemical reaction, causing anodes to disappear quicker. [1, 2]