What are these?(additional anodes)

06Rinker270

I have two of these under swim platform below water line. There is one on either side of the drive.

  

aero3113

I believe they are your mercathodes.

http://www.sterndrives.com/mercathode.html

06Rinker270

Ah yes, they are transom mounted anodes. I guess they are additional to the one connected to the gimbal housing?

Michael T

It's hard to tell rom the picture but they do not seem to have the proper surface appearance to them. Yours is a salt water boat? So these anodes are zinc? If the surface has "glazed-over" they will not be operative.

06Rinker270

I am brackish.  They are not zinc anodes that you replace every year.  From my research, once Aero pointed me in right direction, these are additional anodes for additional protection. Now I wonder if they were added or came with boat.  PO kept boat on lift so why would he add them?  Maybe it's standard with my mercathode system as a whole.  

Michael T

So brackish could be aluminum if they are stand alone. If they are a wired electrical cathode system there will be some wires inside going through the transom wall. If they are not a wired cathode electrical protection system and are stand alone anodes they must be replaced at some interval. I am in fresh water but the boat is kept at and visits marinas where stray shore power currents in the water are a given. Therefore, I use magnesium anodes and replace them every year as they show enough depletion that I couldn't get two years out of them and hauling-out to replace anodes half way through a second summer season would make no economic sense. I have seen anodes that looked new but were the wrong anodes for the water they were being used in and they had "glazed-over" my terminology and looked new. they were useless at that point. I agree that yours could be an add-on electrical cathode protection system but it would have wiring and would have to have continuity to be effective.

06Rinker270

Thank you guys, I will check this weekend if they are wired.  Can I check for continuity using my multimeter?  I hope they are not painted, I don't recall.

@Alswagg, do you know if these come standard on Rinkers of my year or is this something someone added?