How many shaft anodes

MiLoII

Active Member
Jul 14, 2017
138
Southern Lake Michigan
Boat Info
320 Sundancer 2005
Previously 300 Doral 1999
Engines
350 Mag MPI Inboard V Drives
Hello all. My 320 came from brackish/salt water to fresh water so I'm changing all of the anodes over to magnesium. Currently there are 2 anodes on each shaft. If you're in freshwater how many do you use? Do I need 2 on each or I'm wondering did they have them that way because of the saltwater environment?
 
Hello all. My 320 came from brackish/salt water to fresh water so I'm changing all of the anodes over to magnesium. Currently there are 2 anodes on each shaft. If you're in freshwater how many do you use? Do I need 2 on each or I'm wondering did they have them that way because of the saltwater environment?

Congrats on your boat! We don't normally use any shaft anodes in freshwater.

-Tom
 
Well, I don’t recall seeing any anodes on my shafts either, and I am definitely in salt. I don’t leave it in the water, just splash it every 2 weeks or so, but still. Will check again.
 
I'm in fresh/brackish and sometimes salt. The PO of my boat had it equipped with shaft anodes. I've been asking around about the theory to use them or not. Obviously, if you have them, they are "protecting" the shafts. The other side of the coin says that they are not necessary, and if the bolts become loose, they will slide down to the leading edge of the strut, thus blocking the flow of water over the cutlass bearings. This could lead to a failure.

If you think about the geometry of affixing a round object to a shaft with bolts, the anode is very thin to start with where the bolts join the halves together.

Jaybeaux
 
I'm in fresh/brackish and sometimes salt. The PO of my boat had it equipped with shaft anodes. I've been asking around about the theory to use them or not. Obviously, if you have them, they are "protecting" the shafts. The other side of the coin says that they are not necessary, and if the bolts become loose, they will slide down to the leading edge of the strut, thus blocking the flow of water over the cutlass bearings. This could lead to a failure.

If you think about the geometry of affixing a round object to a shaft with bolts, the anode is very thin to start with where the bolts join the halves together.

Jaybeaux
Sea Ray boats do not require nor recommend shaft anodes. And, FYI; a boat can be over "zinc'd" and have consequential cathodic corrosion. Signs of cathodic corrosion might be anti-fouling paint de-bonding from your running gear or possible bearing pitting in the transmission equipment (worst case).... From what I understand one would have to really go overboard on the sacrificial anodes to get into a cathodic corrosion situation.
 
As others said, you don't need anodes on the shafts. Pretty sure the bonding system takes care of them? I also am in salty Pacific water, and I just had my boat hauled out ...shafts looked brand new and were spotless.
 
My boat is in salt 365 days a year (excepting haul out) and no shaft zincs and no problems. So I can't imagine you would need them in freshwater.

M Prod do we have bonding on our shafts, I seen it on the steering/rudders but nothing apparent on the shafts?
 
M Prod do we have bonding on our shafts

I'm not really sure to be honest with you. Like you, my boat sits in salt all year, and when I pulled it two weeks ago, the shafts were spotless. No grime, no growth, you could eat off them. They looked like they had just been polished.

EDIT: On mine there are a series of green bonding wires that also run down near the bottom of the engines toward the starboard and port sides. Wonder if that's it. I read somewhere (can't remember where) that the bonding does in fact protect the shafts and props, etc.
 
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On the bonding I've seen on other boats, a bonding strip is in directly contact with the shaft. But I've seen nothing like that on mine. Here's an example of Masterfab's setup on a 340 which is proabably not factory?

PDR_2004.JPG
 
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No shaft anode here either. I'm in salt for 6 months. If they come loose and block your cutless your in trouble. Just paint them with some prop paint.
 
My boat had them when I got it and I continued to use one on each shaft last year on my 340SDA. I used AL as I am in saltwater. I installed new last April just before splashing and when pulled in November they where only about 30% remaining. I am tossed on this decision for this year as they must be doing something.

-Kevin
 
It's becoming very common in my area to spray the shafts, struts, props and rudders with Rustoleum Cold Galvanizing. This year I'm going to also spray the trim tabs. Because I have Drive Savers I added bonding brushes on the prop shafts behind the couplers.
 
I paint the shafts and props with Propcoat and Pettit ECO the rudders, horns and trim tabs. ALUMINUM anodes go on the tabs and main on back of boat. The unpainted picture is the shaft cleaned before paint. Anodes were never used on this boat.
Prop paint 1.jpg
Bottom paint done.jpg
20161127_112319 (1).jpg
20161127_112324 (1).jpg
Prop paint 1.jpg
Bottom paint done.jpg
 
I paint the shafts and props with Propcoat and Pettit ECO the rudders, horns and trim tabs. ALUMINUM anodes go on the tabs and main on back of boat. The unpainted picture is the shaft cleaned before paint. Anodes were never used on this boat.
View attachment 55079 View attachment 55080View attachment 55081 View attachment 55082 View attachment 55079 View attachment 55080
Nice looking bottom. I hope mine comes out as good. Finish sanding today and start painting. Finally over 50 degrees
 
Thank you everyone for your time and comments. Clearly at 2 per shaft it appears to be overkill. I did an informal survey st my boatyard (skulked around and looked at all the shaft boats still on the hard). Many had one anode some had none Im going to go down to one this year and then check next year at layup.
 
It's becoming very common in my area to spray the shafts, struts, props and rudders with Rustoleum Cold Galvanizing. This year I'm going to also spray the trim tabs. Because I have Drive Savers I added bonding brushes on the prop shafts behind the couplers.

I just went this route this year. Props, shafts, exhausts, rudders and tabs all with the Rust-Oleum cold galvanizing compound. Previously there was prop speed on but I did not feel it was worth the time, effort or money.

-Kevin
 
I sprayed my props, shafts, rudders and tabs with Rustoleum Cold Galvanizing last weekend to see how it holds up this year.
The previous owner of my boat had anodes on the shafts, the mechanic at Marine Max told me before I took delivery last year that they shouldn’t be on there so he left them off.
I didn’t put them on this year either.
 
I sprayed my props, shafts, rudders and tabs with Rustoleum Cold Galvanizing last weekend to see how it holds up this year.
The previous owner of my boat had anodes on the shafts, the mechanic at Marine Max told me before I took delivery last year that they shouldn’t be on there so he left them off.
I didn’t put them on this year either.

I am leaning towards leaving the off this year too. @mnm99 - thanks for the feedback. Since we have similar boats I hope to see the same results. I also have anodes on my sea strainers and bow thruster to deal with in addition to the main and the tab anodes.

-Kevin
 
My Vetus 9524 Thruster anode was pretty easy to change. A Phillips screwdriver and 3mm Allen key was all that was needed.
Next year I’ll remember to bring a “T” handle Allen key from home to make it a little easier.
 

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