Anodes

[kbradatzke]

Hi
I have a boat that I bought last year and the anodes had about one season left in them ( it was a lift keep salt water boat) . I would like to change them this year , the boat is keep on a trailer when not used. The only time we ever hook up to shore power is when we take it to the west coast for a couple weeks in the summer this year we won't be making out and it will be fresh water only. I have found that on my last boat that anodes last me a long time with keeping the boat stored out of the water and assume this will be the case for this boat also. I have read that zinc anodes are for salt water and aluminum will work in both . Should I just be putting on aluminum for my combination of salt and fresh that we normaly do?

 

[JoeBTB]

Personally, I don't think I'd sweat the decision at all, given that most of the time the boat is out of the water. I'd use whatever is easiest to find, and change them only when they're 50% gone.

 

[wayne.alexander]

kbradatzke
There's some bad information out there about aluminum anodes. Don't buy into the rumor that aluminum works in fresh water. Zinc and Aluminum anodes both work in salt water, but both have problems in fresh water. The good news about that is that fresh water creates only a small amount of corrosion, and anodes aren't needed as badly as in saltwater. Magnesium works best in fresh water environments.

Any anode will work "ONLY" while it's submerged in water (or any electrolyte). In your case, with the vessel out of the water most of the time, the anodes can't do their job. That's why they last so long. There's no transfer of current. If you're only going to salt for a week a year, there's no need to worry about anodes, but you should look into magnesiun anodes for the freshwater situation.

 

[DDL]

wayne.alexander

I have both aluminum and zinc anodes and keep my boat in a covered slip on Lake Union (fresh water) but do almost all our boating in saltwater. My service people tell me that the anodes actually develop a crust like coating that impairs their effectiveness from sitting in fresh water. Is that your experience? I'm also advised that this coating can be sanded away. As a matter of fact we're being hauled this Friday for an anode check and to change the oil in my IPS drives. Since my boat spends the vast majority of it's time in fresh water should I suggest magnesium? I haven't had problems with my other boats operated under the same conditions but I do have a lot of bronze hanging under the boat so I'd rather be safe than sorry (hence the haulout to change drive oil after only 200 hours).

 

[Philyteach]

Funny thing. We had a professional surveyor at my CGAux Flotilla meeting tonight. The Delaware River is fresh in the north, brackish around Chester and Salty around Wilmington (bout a 1/2 hour 45 minute trip for those not familiar). I asked her what I should use. She insisted that aluminum is the only way to go, regardless of fresh or salt...and that's all she uses. I guess I'll go with her opinion this year. I had magnesium on last year and they need replacing (yup proves they were working).