how often to clean anodes?

[lucky7]

just spent 2 weeks on vacation with the boat in the water the whole time. i was surprised to see some paint off my drive, several inches worth. my anodes were chalky looking, fresh water, never occured to me to clean them off. for the rest of the year its a trailer boat. should i have cleaned them? how often?
thanks

 

[lucky7's]

Re: how often to clean anodes?

You want to check for actual erosion of the metal itself not cleanliness. You should replace them when the are 30-40 percent eroded. That means when 30-40 percent of the metal is gone. See when you run you boat in the water the spinning propeller creates electrolylsis. The zinc metal is there because it gives up electrons more easily than the metal used to make your outdrive. So the zinc will corrode or oxodize faster than your outdrive..