Barnacles Lake Washington

[Mastercraft]

I have a significant build up of barnacles on 3 month old aluminum anodes in Lake Washington. Did not see salt water. Barnacles are just on all anodes. Any explanation why I have barnacles in fresh water and just on anodes???

 

[dbsea]

are you sure it's actually barnacles? Anodes get this "crusty" appearance as they start to age and it can almost look like barnacles. That said, 3 month old anodes should not have deteriorated that much. I would be concerned about galvanic corrosion where you're keeping the boat.

 

[Martin610]

Are you sure you have the correct anodes installed? If Lake ashington is fresh water you would want to have fresh water anodes, which are not zinc.

 

[tlkenyon]

Is it possible that the anodes are the only thing not painted with anti-fouling, hence the only place with growth?

 

[Pandion]

Our R27OB has been in Lake Washington for the past three months, as well. Our trim tab anodes (aluminum) have the same appearance, but I believe it is a result of normal corrosion of the anode. While it looks like barnacles, it is a fairly soft coating on the anode surface that can be brushed away.

Steve D'Antonio, who I believe is a knowledgeable source, describes it as aluminum hydroxide. Check this article about 3/4th of the way down:

https://stevedmarineconsulting.com/...rosion-protection-level-editorial-old-vs-new/