How do you know if my anode needs replacement?

[vallkor]

Hi experts,.need your help!

I bought a 2005 beneteau 373 (USA) which sits in the lake water in Texas the whole life, here is a photo of prop, it seems anode is still there but how do you know if it needs replacement?

Also, it is pretty dirty, does this dirt allows it to do its function properly?

The boat is in marina most of the time connected to shore power. There is no ability currently to easily take the boat out of water unfortunately.

Thanks!

 

[Project_Mayhem]

I can't tell by the pics but what I can tell you, is that fresh water boats should have magnesium, not zinc, anodes. My boat has been in the Great Lakes all its life. I just replaced what is likely the original anodes after 32 years. Most boats come with zinc.

 

[jssailem]

The only way I know to check the anode without diving under the boat or hauling the boat up on shore is to use a silver/silver-chloride (Ag/AgCl) reference electrode and check the corrosion potential on your boat.

BoatZincs has the tool and the information on this subject.

Corrosion Reference Electrode (CRE) with User's Guide

Corrosion Reference Electrode (CRE) with User's Guide | BoatZincs.com | America's Superstore for Marine Anodes

boatzincs.com

 

[kappykaplan]

Also, it is pretty dirty, does this dirt allows it to do its function properly?

The marine growth will impact your ability to achieve max RPM. It should be cleaned.

 

[Will Gilmore]

Fresh water isn't a very good electrolytic, which means galvanic corrosion doesn't really work very well in fresh water. There are minerals and salts desolved in the water, so it isn't zero. What can't be said is what the properties of that growth are. I've notice different plants conduct electricity more or less than other plants. For example, grass doesn't ground out my electric fence, but even a little burdock will. So it would be a good idea to keep your bottom clean, just in case.

-Will

 

[BigEasy]

My understanding is to replace the anode when it becomes 50% depleted. That being said, monitor your waterline for signs of excess fouling & have a diver (or yourself) clean the bottom when the growth buildup is sufficient. That is also an opportunity to inspect & clean the prop & shaft. Also inspect & clean the anode; replace the anode if 50% consumed.