Anode question. This stuff is confusing.

[SeaEsta-12]

Hello all!
Need a little help/ clarification.

I have a boat that is only used in salt water and currently has zinc anodes. I will be moving the boat permanently to fresh water and need to change out my anodes to magnesium.
Here is where my question arises. The boat was originally purchased to be used in salt water, so when the previous owner bought it, he had a corrosion system from Volvo Penta installed. The boat has three locations for anodes (Drive, transom plate and hull plate)
For the life of me, i can NOT get the hull plate anode off. I dont think that anode has ever been replaced in the past 10 years. the Nuts are frozen on, and when I try to loosed them, the bolt is turning from the inside of the boat.
Would I be creating a mess if i just left that anode on? it seems pretty deteriorated already.
I will be in fresh water only, and from what I understand, the VP corrosion system is only used in salt and brackish water.

What are my options in this case? I plan on disconnecting the corrosion system from the battery. Good idea? No need to? or bad idea?

I have the older system. which looks like this.


Thank you all!

 

[alldodge]

Don't disconnect it, you can use a mix of anode types, not he best protection for the boat, but better then not having one. The anode system is used for all types of water not just the ones you listed. I've been in fresh water always, and without my system the drive and other components will get eaten up.

bolt is turning from the inside of the boat.

Since they turn now, they may start leaking later. Have you tried heat?

And is this an inboard with V or straight drives?

 

[SeaEsta-12]

The hull anode is very eaten away, so I am sure its not doing much of anything now at this point.
the boat is an I/O with Volvo Penta outdrive.

I have not tried heat yet. Ill give that a shot.

 

[SeaEsta-12]

No Title

WTH!! This is confusing now. Has anyone else run in to this issue?
So, I ordered the "kit" for my VP DP-SM 1.95 outdrive and I got both anodes (as shown in the pic) one for transom plate and the other for the outdrive.

The outdrive one went one like it should, but then when I went to put on the transom plate one, it doesn't FIT!!!! the bolts are much thicker than the holes for the anode.
I went and looked at another outdrive similar to mine and I see that they have two small cubes to each side.
Sooooo.......is my outdrive some special edition that requires those cubes?
Attached is a picture of my outdrive.

 

[alldodge]

Here is an image for anode locations



Maybe Maclin or Scott Danforth can help

 

[SeaEsta-12]

That image does not show my outdrive version though. the anode is shows is what I have now, but they dont fit.

 

[alldodge]

Not the expert on your drive but I think you have what looks like an OMC and may have been during the time VP was buying OMC. There is also a possibility that the anodes were installed there but not actually the real location, just guess. Here is a PDF file which has more info but still does not show a location where yours was

View attachment anode-location-flyer.pdf

 

[JoLin]

I ran into a similar issue the first time I bought anode 'kits' for my Alpha's. The standard kit was assembled to fit drives that don't have the Mercathode active ant-corrosion system, so those anodes were useless. Mine are still in good shape so I left them alone. The first year or 2 of Gen 2 drives did not have the 'tapped' end caps on the trim rams, so those anodes were useless, too. I had to order 'donut' zincs that clamp to the trim rams. Since then, I order the individual anodes I need from 'zincs.com'.

Your issue is that the anode you need for the Volvo ant-corrosion system is probably not available as part of a kit. You'll need to find and order it separately.

My .02